|
|||||||||
|
|
|
|
|
|
|
|
|
|
|
TRANSPLANTATION
From the Division of Research Immunology/Bone Marrow
Transplantation, Childrens Hospital Los Angeles, CA; Division
of Bone Marrow Transplantation, Department of Pediatrics, Cancer
Center, University of Minnesota, Minneapolis, MN; Department of
Internal Medicine, University of Texas Southwestern Medical Center, and
the Sammons Cancer Center, Baylor University Medical Center, Dallas TX.
Hematopoietic stem cell transplantation (HSCT) is followed by
profound immunodeficiency. Thymic function is necessary for de novo
generation of T cells after HSCT. Circulating CD45RA+ naive
T-cell levels are predictive of antigen-specific T-cell responses in
the absence of graft-versus-host disease (GVHD). These T cells may not
represent recent thymic emigrants, since naive T cells may maintain
this phenotype if not antigen-activated. To accurately measure thymic
output after HSCT and determine the factors that influence thymic
function, T-cell receptor excision circles (TRECs) were examined in
CD4+ and CD8+ cells from a cross-section of
patients following HSCT. TREC levels rose weeks after HSCT and
could be detected in patients 6 years after HSCT. TREC levels
correlated with the frequency of phenotypically naive T cells,
indicating that such cells were not expanded progeny of naive T cells
present in the donor graft. Chronic GVHD was the most important factor
that predicted low TREC levels even years after HSCT. Patients with a
history of resolved GVHD had decreased numbers of TREC, compared with
those with no GVHD. Because few adults had no history of GVHD, it was
not possible to determine whether age alone inversely correlated with
TREC levels. Recipients of cord blood grafts had no evidence of
decreased TREC induced by immunosuppressive prophylaxis drugs. Compared
with unrelated donor grafts, recipients of matched sibling grafts had
higher TREC levels. Collectively, these data suggest that thymopoiesis is inhibited by GVHD. Larger studies will be needed to determine the
independent contributions of age and preparative regimen to post-transplant thymopoietic capacity.
(Blood. 2001;97:1458-1466) Following hematopoietic stem cell transplant
(HSCT), there is a prolonged period of profound immune deficiency,
which includes defects in thymopoiesis.1 This immune
deficiency contributes to the high incidence of opportunistic
infection, which continues for years after HSCT.2,3 The
etiology of the immune defect is multifactorial. Thymopoietic defects
resulting in decreased ability to generate new T cells after HSCT are
important since complete immune reconstitution ultimately depends on
the generation of new T cells from hematopoietic stem cell (HSCs), just
as long-term myeloid and erythroid reconstitution depends on HSC
engraftment. Transfer of committed progenitors or mature donor-derived
T cells may permit short-term immune function. Analyses of patients
after HSCT have demonstrated that the presence of immune function at 1 year or later was correlated with the number of
CD4+CD45RA+ naive T cells, suggesting that
immune function at later time points is dependent on the ability to
generate new T cells.4,5
The factors that inhibit thymic function may include age,
graft-versus-host disease (GVHD), and direct thymic damage from chemoradiotherapy. In multiple studies of normal individuals, recipients of high-dose chemotherapy, HSCT recipients, and patients infected with human immunodeficiency virus, age has been inversely correlated with thymopoiesis.4-7 GVHD after HSCT also
leads to thymic insufficiency, possibly by direct attack on the thymic stroma by allogeneic effector cells.8,9 Confounding the
understanding of the role of GVHD in the pathogenesis of post-HSCT
immune deficiency are the immunosuppressive effects of the medications
used to prevent or treat GVHD. Besides age and GVHD, direct damage to
the subset of thymic epithelial cells leading to loss of production of
the thymopoietic cytokine interleukin-7 (IL-7) and consequently
decreased ability to support post-HSCT thymopoiesis has been shown in a murine model of HSCT (Chung et al, unpublished data, January
2001).10
Several methods have been used to measure thymopoietic capacity. Thymic
size as measured by volumetric computerized tomographic measurements
has been correlated with numbers of CD4+CD45RA+
naive T cells.6,11 The number of phenotypically naive T
cells has been shown to correlate with antigen-specific
function.2,3 However, there are concerns about limitations
of estimating thymic function on the basis of naive T-cell phenotype
alone. T cells expressing a naive phenotype are not necessarily
accurate surrogate markers of thymic function. Following thymic
emigration, CD45RA+ naive T cells can have a long quiescent
life span,12,13 may proliferate in an antigen-independent
manner,14 or may rapidly convert to CD45RO+
memory/effector phenotype T cells.15 Furthermore, naive
T-cell markers may be acquired by memory T cells,15 and
naive and memory cells may have overlapping phenotypes, especially
among CD8+ T cells.16,17
A different assay that has been more recently used as a measure of
thymopoietic capacity is the frequency of T-cell receptor excision
circles (TRECs) among peripheral blood T cells. A byproduct of T-cell
receptor rearrangement includes a circular episome of DNA, which is
stable and does not replicate with cellular
proliferation.7,18 Because recent thymic emigrants (RTEs)
have TRECs at levels that would not have been affected by peripheral
expansion and cellular replication, quantification of TREC levels after
HSCT represents a sensitive measurement of thymopoietic capacity
leading to the generation of mature peripheral blood T cells after HSCT.
In this study, we examined levels of TRECs in CD4+ and
CD8+ lymphocytes from patients after HSCT. The first
recipients studied were a cohort of patients in a cross-sectional
analysis of TREC levels. As data from the cross-sectional analyses
indicated an inverse relationship between GVHD and TRECs, we then
prospectively analyzed a smaller cohort of recipients of umbilical cord
blood cells (CBCs) who received prophylaxis for GVHD. The
results indicate that GVHD and age were the most important predictors
of low TREC levels after HSCT, but that the administration of standard
immunosuppressive medications did not affect TREC levels.
Patients
GVHD management and scoring
Cell isolation Blood samples were collected in heparinized tubes for isolation of peripheral blood mononuclear cells (PBMCs). After Ficoll-Hypaque density centrifugation, the CD4+ or CD8+ T cells were isolated from the mononuclear cells by MACS magnetic microbead separation (Miltenyi Biotec, Auburn, CA).Flow cytometry To quantify phenotypically naive T cells in CBC recipients, PBMCs were stained with fluorochrome-conjugated antibodies against CD4, CD8, CD45RO, and CD27 (Becton Dickinson, San Jose, CA) and analyzed by 4-color flow cytometry (FACSCalibur, Becton Dickinson). Naive T-cell percentages in each CD4+ or CD8+ subset were measured by gating on CD45RO CD27+ cells by
means of Paint-a-Gate software (Becton Dickinson). To quantify
phenotypically naive CD4+ T cells in the other study
subjects, PBMCs were stained with fluorochrome-conjugated antibodies
against CD4 and CD45RA, (Becton Dickinson). Naive CD4+
T-cell percentages were measured by gating on
CD45RA+CD4+ cells.
Measurement of TRECs in sorted cells Quantification of TRECs in sorted CD4+ and CD8+ T cells was performed by real-time quantitative polymerase chain reaction (PCR) by means of the 5' nuclease (TaqMan) assay with an ABI7700 system (PerkinElmer, Norwalk, CT) as previously described.7,28 CD4+ and CD8+ cells were lysed in 100 µg/mL proteinase K (Boehringer, Indianapolis, IN) for 1 hour at 56°C, and then 10 minutes at 95°C, at 107 cells per milliliter. Real-time quantitative PCR was performed on 5 µL of cell lysate (equivalent to 50 000 cells) with the primers 5'-CACATCCCTTTCAACCATGCT and 5'-GCCAGCTGCAGGGTTTAGG, and probe FAM-5'-ACACCTCTGGTTTTTGTAAAGGTGCCCACT-TAMRA (MegaBases, Chicago, IL). PCR reactions contained 0.5 U Platinum Taq polymerase (Gibco, Grand Island, NY) and 3.5 mM MgCl2, 0.2 mM dNTPs, 500 nM of each primer, 150 nM probe, and Blue-636 reference (MegaBases). Conditions were 95°C for 5 minutes, 95° for 30 seconds, and 60° for 1 minute for 40 cycles. A standard curve was plotted, and TREC values for samples were calculated by the ABI7700 software. Samples were analyzed in duplicate.Statistical analyses Statistical analyses (2-tailed Mann-Whitney test [P values]), and Spearman's rank correlation coefficients (r values) were calculated by means of Excel and Prism software. An r value greater than 0.3, or less than 0.3, and a
P value less than .05 were considered significant.
Patient cohorts for cross-sectional analysis As shown in Table 1, there were 67 patients with primary diagnoses of acute leukemia, chronic myelogenous leukemia, lymphoma, aplastic anemia, severe combined immunodeficiency (SCID) or other primary immunodeficiencies, or other genetic diseases. All patients, including those with SCID, received HSCT after ablative chemotherapy or chemoradiotherapy. For purposes of analysis, patients were divided into those younger or older than 25 years of age (Table 1). Patients 25 years of age or younger could be divided into approximately equal numbers of patients who either had never had clinical GVHD (21 patients), had had a previous history of an episode of GVHD but no clinical GVHD at the time of TREC analysis (17 patients), or had clinical GVHD at the time of analysis (18 patients). Of the 11 patients older than 25 years of age, only 1 had no history of GVHD; 6 had a previous history of an episode of GVHD, and 4 had clinical GVHD at the time of analysis.TREC levels in patients without GVHD TREC levels were measured in a cross-section of children and adults through the age of 25 years following HSCT with bone marrow as the stem cell source (Figure 1A,D). By 2 months after HSCT, the levels of TREC had risen, especially in those who had no GVHD. In the group of patients with no GVHD, TREC levels were highest 1 to 2 years after HSCT, but were found to be comparably high (10 000 to 30 000 TRECs per 105 T cells) in patients at 3 to 7 years. The rise in TREC levels was observed among both CD4+ and CD8+ T cells. These data (and other data not shown at time points soon after HSCT) indicate that TREC levels can increase substantially beginning 2 months after HSCT in children and adults who have no history of GVHD.
TREC levels in patients with GVHD Patients with GVHD were divided into 2 groups for analysis. Some patients with no clinical evidence of GVHD at the time of study had prior histories of either acute or chronic GVHD; other patients were studied with concurrent chronic GVHD. In both patient populations, the levels of TRECs were lower than in the patients who had no history of GVHD (Figure 1B-D). The decreased levels of TRECs were most profound in the group of patients with active chronic GVHD at the time of study. In this group of patients, TREC levels were typically lower than 2000 TRECs per 105 T cells, irrespective of the time period after HSCT. TREC levels were significantly lower among both the CD4+ and CD8+ T cells in the active chronic GVHD group (P < .0001 for both CD4+ and CD8+ T cells).In the patients with a history of GVHD but no current GVHD, TREC levels were also lower than normal, but were significantly higher than those observed in the chronic GVHD group (Figure 1C-D). The decrease in TREC levels in the patients with a history of GVHD compared with the group with no GVHD was significant for CD4+ T cells (P = .0017), but not CD8+ T cells (P = .70). The TREC levels were higher in the group of patients with a history of GVHD than in those with active chronic GVHD (P < .0001 for CD4+ T cells and P = .0003 for CD8+ T cells). Figure 1D shows a composite figure of the range and median levels of TRECs in the CD4+ and CD8+ cells for patients up to 40 months after transplant in the 3 GVHD groups. Relationship of TREC levels to age Because thymic function and TREC levels normally decrease with age, we examined whether TREC levels and age were inversely correlated after HSCT. In the group of patients with no GVHD, there was no correlation between TREC levels and age (r =0.2631, 95% confidence interval [CI] = 0.6322 to 0.2035, P = .25, for CD4+ cells; and
r = 0.1475, 95% CI = 0.5547 to 0.3160, P = .25, for CD8+ cells). However, because of
the confounding relationship between older age and GVHD, there was only
one patient older than 25 years of age who did not develop GVHD and who
was excluded from the analysis. Thus, through age 25 years,
age had no effect on TREC levels if there was no history of GVHD.
Furthermore, in all patients with active chronic GVHD, TREC levels were
similarly unaffected by age (r = 0.0792, 95%
CI = 0.3557 to 0.4859, P = .272, for CD4+
cells; and r = 0.2488, 95% CI = 0.0195 to 0.6078, P = .25, for CD8+ cells).
In all patients with a history of GVHD but no active chronic GVHD,
there was a significant inverse relationship between TREC levels and
age for both CD4+ T cells (r = CBC recipients Because GVHD and age were such significant determinants of TREC levels, we next prospectively analyzed a cohort of patients with a low risk of GVHD. Umbilical CBC transplants are associated with a lower incidence of GVHD than marrow or mobilized peripheral blood stem cell transplants, for any given degree of histoincompatibility.23,24 The patients who had received CBCs were analyzed prospectively for TREC levels up to 33 months after transplant. These patients received prophylactic immunosuppression with cyclosporine and glucocorticoids, with or without ATG. The CBC recipients developed TREC at levels consistent with the cross-sectional analysis of the marrow transplant patients (Figure 2). Indeed, TREC levels rose to supranormal levels for age in many of the patients, perhaps reflecting what has been termed thymic rebound.6 The presence of clinical GVHD was found to inhibit a rise in TRECs, but TREC levels increased when GVHD was not active. In 3 patients, although immunosuppression was continued for at least 6 months in the absence of GVHD, TREC levels nevertheless increased (Figure 2). These data indicate that in the absence of GVHD, prophylactic immunosuppressive agents did not preclude thymopoiesis from occurring, as measured by rises in CD4+ and CD8+ TREC levels. However, it should be stressed that although this conclusion may be valid, more patients and comparisons with an age-matched group without immunosuppression will be required before more definitive conclusions can be made.
Matched unrelated vs histocompatible sibling donors Previous studies have indicated that HSCT from MUDs was associated with lower numbers of CD45RA+ cells after HSCT than when histocompatible sibling marrow donors were used, especially in the context of clinical GVHD.5 TREC levels in the younger age group (through age 25 years) were significantly lower in recipients of MUD-derived HSCT than in recipients of histocompatible cells when analysis was done across all GVHD groups (P = .0007 for CD4+ T cells and P = .0073 for CD8+ T cells). The lower levels of TRECs in the MUD recipients were observed whether or not the unrelated CBCs were included in the analysis (P = .0007 for CD4+ T cells and P = .007 for CD8+ T cells, when CBC recipients were excluded). However, when the comparison between TREC levels in recipients of MUD-derived HSCT and histocompatible cells was performed separately within the no-GVHD, history-of-GVHD, and active-chronic-GVHD groups, then there was no significant difference, and it became clear that the lower TREC levels in the recipients of MUD-derived HSCT resulted from their increased incidence of GVHD. At older ages, age itself became a confounding factor, and the correlations between donor type and TREC levels were not significant (P = .05 for CD4+ T cells and P = .29 for CD8+ T cells).Relationship between frequency of TRECs and CD4+CD45RA+ or CD8+CD45RA+ cells Previous studies of immune reconstitution in chemotherapy and HSCT recipients have used the cell-surface molecule CD45RA as a phenotypic marker of naive T cells.4-6 The frequency of TRECs and CD45RA+ T cells was compared in the CD4+ T cells from all patients in the cross-sectional analysis of this study. TREC levels and CD45RA+ cell numbers were significantly correlated. The correlation was present regardless of whether the patient had no GVHD (r = 0.5353, 95% CI = 0.092 71 to 0.8013, P = .0182), a history of GVHD (r = 0.6882, 95% CI = 0.3639 to 0.8636, P = .0004), or chronic GVHD (r = 0.7065, 95% CI = 0.4043 to 0.8696, P = .0002). The percentage of CD45RA+CD8+ T cells was not determined in these patients. Among the prospectively studied CBC recipients, TREC levels correlated significantly with the number of naive (CD45ROCD27+) CD4+ cells
(r = 0.7262, 95% CI = 0.5435 to 0.8432, P < .0001) and naive CD8+ cells
(r = 0.5235, 95% CI = 0.2598 to 0.7145, P = .0003). The correlation of RTEs, as measured by TRECs,
with the number of naive T cells suggests that most of the naive T
cells were generated de novo.
The major findings of our study are the following: (1) TREC levels rose weeks after HSCT despite immunosuppressive GVHD prophylactic agents; (2) TREC levels correlated with the frequency of naive phenotype T cells, indicating that such cells were not the expanded progeny of naive T cells present in the donor graft; (3) active chronic GVHD was the most important factor that predicted low TREC levels even years after HSCT; (4) patients with a history of resolved GVHD had decreased numbers of TRECs compared with those with no GVHD; (5) age did not affect TREC levels in patients with no GVHD through the age of 25 and had no effect on TREC levels of patients with active chronic GVHD at all ages; and (6) in patients with resolved GVHD, there was an inverse correlation between age and TRECs above the age of 16 years. These data indicate that a history of GVHD, presence of GVHD, and age, but apparently not the administration of immunosuppressive agents per se, were critical determinants of thymic output after HSCT. Immune reconstitution after HSCT is increasingly recognized as a critical problem because it is a determinant of morbidity and mortality from opportunistic infections in recipients. Post-transplant T cells are derived from both mature T cells present in the donor graft and T cells that develop de novo in the recipient from transplanted donor stem cells. It is likely that the latter pathway of differentiation leads to long-term immune reconstitution, whereas the former results in transient adoptive transfer of immunity as well as GVHD mediated by cells with alloreactivity toward recipient antigens. Over the past decade, a variety of techniques have been used to characterize the development of donor-derived T cells in the recipient after HSCT. The measurement of peripheral T-cell TRECs allows the quantification of T cells that have not undergone post-thymic clonal expansion. Because TRECs are rapidly diluted by clonal expansion, TREC levels probably better reflect the RTE population. The TREC assays described in this study were performed on sorted CD4+ and CD8+ T lymphocytes. This technique makes it possible to examine each T-cell population, which may have different dynamics of production or peripheral expansion. Furthermore, analyses of enriched T cells prevents artifacts caused by varying levels of non-T cells, such as monocytes, which affect the results of TREC studies that use only unfractionated PBMCs. In our cross-sectional analyses, TREC levels correlated with phenotypically naive T-cell numbers in the adult HSCT recipients and in the pediatric transplants. The time delay between HSCT and the appearance of TRECs, and the correlation between TRECs and numbers of phenotypically naive T cells, suggest that the majority of naive T cells were RTEs, rather than the products of clonal expansion of pre-existing naive T cells that had been infused with the donor HSC product. Because the naive phenotype can be maintained by cells for long periods after thymic emigration and even after expansion in the periphery, TRECs are a more accurate measure of post-transplant thymic output.11-13 Peripheral expansion of naive T lymphocytes in the absence of thymic function can occur, resulting in changes in naive T-cell numbers independent of changes in TRECs29; therefore, the measurement of TRECs can determine the origin of T cells bearing a naive phenotype. This is all the more important given the degree of overlap between phenotypes among naive and memory T cells.16,17 Furthermore, increases in TREC levels can be detected much earlier than increases in naive T cells.7,28 Thus, the TREC assay will be useful in studies of thymic output after HSCT and can complement phenotypic analysis of T cells while avoiding the confounding variables associated with accurate definition of naive T-cell numbers. We observed that TRECs rose to high levels, often above normal for age, early after allogeneic HSCT in children and adults in whom GVHD did not occur, indicating that the thymus was playing a role in immune reconstitution. The major correlate of low TRECs after HSCT that we observed was the presence or history of GVHD. Patients with chronic GVHD had no evidence of the early rise in TREC levels observed in the first 2 years after HSCT and had persistently low TREC levels up to 10 years after transplant. Patients with a history of prior acute or chronic GVHD also had lower CD4+ and CD8+ T-cell TREC levels than the patients with no history of GVHD, and this was statistically significant for CD4+ cells but not CD8+ cells. MUD transplantation was also associated with lower levels of TRECs and reflected the observation that GVHD occurred more frequently in MUD recipients than in recipients of histocompatible sibling cells. GVHD is a complex phenomenon that could affect thymic function in
many ways. Because GVHD is treated with immunosuppressive drugs that
may affect thymic function, any observed effect of GVHD on TREC levels
could be due to such drugs. The relative roles of GVHD and
immunosuppressive drugs can be examined more critically in the cohort
of patients who received CBC transplants. Some CBC recipients did not
develop GVHD, but did receive prophylactic immunosuppressive
treatment with cyclosporine and glucocorticoids. In spite of
immunosuppression, these CBC recipients who were followed serially
developed TRECs normally in the first year after HSCT. Rodent studies
have indicated that the administration of cortisone to animals
undergoing a graft-versus-host response results in a reduction of
mature thymocytes, particularly those bearing the CD4
antigen.30 Although exogenous glucocorticoids are known to
cause thymocyte apoptosis in vitro, little is known of their effect on
thymic output in humans.56 Thus, the observed continued increase in TREC levels in spite of continued glucocorticoids was
unexpected. Cyclosporine administration also did not prevent the
generation of RTEs as measured by TREC levels. Cyclosporine administration has been shown to alter thymic selection mechanisms in
nontransplanted rodents and in syngeneic BMT recipients.31 Cyclosporine administration to nontransplanted rats has been shown to
reduce immature cortical thymocyte numbers, deplete medullary CD4+CD8 GVHD is caused by alloreactive or autoreactive T cells transferred into
the recipient along with the HSCs. As the pool of potential HSC donors
expands to include those who are increasingly disparate from the
recipients, the frequency and severity of GVHD are rising. Patients
with GVHD most frequently succumb to opportunistic infections, yet the
mechanisms responsible for the immunodeficiency associated with GVHD
are unclear. Our data provide evidence that thymic dysfunction caused
by GVHD is an important component of the observed immune deficiency. In
rodents, GVHD has been shown to result in the elimination of both
immature CD4+CD8+ and mature
CD4+CD8 The evidence for a deleterious effect of GVHD on thymic function notwithstanding, it must be stressed that the TREC content in a cell population is affected not only by changes in thymic output but also by the proliferative history of the cells. A measured increase in TREC levels in the naive T-cell compartment is likely to reflect thymic output more directly when the rate of peripheral T-cell division is low or constant. However, in the setting of GVHD, it is quite likely that the rates of T-cell division may be altered and thus lead to an underestimate of the rate of thymic output. It should also be appreciated that in patients with previous but now quiescent GVHD, low TREC levels may indicate either that previous thymic injury prevents TREC generation, even in situations in which homeostasis may be reset, and/or that the new thymic emigrants are expanding and diluting out the number of TRECs until T-cell homeostasis is re-established. In the latter case, the true number of RTEs would be underestimated by the TREC analysis performed in the present study. To distinguish between the effects of peripheral T-cell turnover and thymic output on TREC levels, it will be necessary in future studies to measure changes in TRECs within naive T-cell subsets and an independent marker of cell turnover such as Ki67 expression. An alternative interpretation of the relationship between GVHD and TREC levels, which we cannot exclude, is that antecedent thymic dysfunction occurring as a consequence of chemotherapy6 or the aging process7 hindered the development of thymic-derived regulatory T cells after HSCT, contributing to the development of GVHD. Indeed, studies in rodents have shown that thymectomized mice are more susceptible to GVHD induction than euthymic mice.46,47 Other aspects of HSCT have also been proposed as causing thymic dysfunction. Increasing age has been previously shown to be negatively correlated with numbers of naive T cells observed after HSCT or high-dose chemotherapy.5-7 Age has also been shown to be correlated with the risk of GVHD after allogeneic HSCT. However, in our study, GVHD and not age was the most important predictor of TREC levels. Age was inversely related to TREC levels only among patients with a history of GVHD, but not in those with either no GVHD (through age 25 years) or chronic GVHD. In previous studies, age was negatively correlated with naive T-cell numbers in patients without GVHD as well as in recipients of MUD bone marrow.4,5 Similarly, studies of recipients of autologous HSCT for multiple myeloma showed an inverse relationship between TREC levels and age.28 Because of the observed powerful effect of GVHD on TREC levels, our current study is confounded by the association of increased age with GVHD, so that in patients with no GVHD we were only able to make significant correlations with TREC levels through age 25. Critical examination of autologous HSCT recipients and larger numbers of allogeneic HSCT recipients will be necessary to determine whether the previously observed effects of age on thymic function after HSCT are independent of the increased incidence of GVHD. Similarly, our study was not able to determine whether there are pretransplant conditioning regimens, such as TBI, that cause more thymic damage than other regimens. Studies of TREC levels in larger cohorts of patients randomized among regimens will be necessary to address the question of whether some forms of conditioning are more deleterious to thymic function than others. A recent report in a cohort of infants with SCID demonstrated that although TRECs appeared in the first year after haplo-identical bone marrow transplantation (BMT), TREC levels declined after the second year and became undetectable in patients receiving a transplant more than 10 years earlier.48 In the present study, patients had rising TREC levels in the first 1 to 2 years after HSCT, in a manner similar to that reported by Patel et al.48 However, at 3 to 7 years after HSCT, some of the patients whom we describe had TREC levels that were nearly 10 times higher than reported in the cohort of SCID patients reported previously. The patients in the present study differ from the previously reported SCID patients in that all of the patients in the present study, regardless of diagnosis, received ablative chemotherapy or chemoradiotherapy in order to achieve HSC engraftment. Thus, patients in our study had donor HSCs whereas the SCID patients reported by Patel, who did not receive pre-HSCT preparative therapy, may have had persistent recipient HSCs with intrinsic defects in T-cell maturation. An alternative explanation for the apparently poorer thymic function observed in the previously reported SCID patients is that the intrinsic defect in thymic progenitors in SCID results in severe, irreversible thymic damage, a phenomenon that has been observed in a murine model.49 Several strategies to improve post-HSCT thymic function are logical developments of our study. First, early successful prevention of GVHD may result in less thymic damage and improved long-term production of T cells. Increased thymic production of T cells is likely to increase the repertoire of T cells28 and possibly decrease the high incidence of infection that has been observed after HSCT.2,3 Novel strategies to prevent GVHD by induction of tolerance have been described in murine,50-52 preclinical human,53 and clinical human studies.52,54 Successful tolerance induction by cytokine adminstration or blockade of costimulatory pathways may also be able to prevent the thymic damage that has been observed in GVHD. Thus, prospective analyses of TREC levels in studies of GVHD prevention and treatment will be useful in determining whether the intervention was successful at preventing thymic damage caused by GVHD. Secondly, administration of thymopoietic cytokines may be able to increase thymic function after HSCT. IL-7 is a stroma-derived cytokine that is a major growth factor for thymopoiesis and that is normally produced by thymic epithelial cells. Systemic administration of recombinant IL-7 to murine BMT recipients normalizes thymopoiesis and improves post-BMT immune function.55 Clinical studies of IL-7 have not yet been instituted; monitoring of TREC levels in such studies will be a useful measure of the effects on thymopoiesis. In summary, we have provided evidence that thymopoiesis as measured by peripheral blood CD4+ and CD8+ T-cell TREC levels occurs in children and adults after allogeneic HSCT and is adversely affected by GVHD, even if the GVHD is not active. The presence of active chronic GVHD was a major barrier to thymopoiesis. Patients receiving MUD transplants had lower TREC levels than those receiving sibling donor grafts. Umbilical cord blood transplant recipients had no evidence of inhibition of thymopoiesis despite being maintained on immunosuppressive drugs. These data indicate that strategies to restore thymopoiesis will probably be required for patients who have a preceding history of GVHD.
The authors thank Drs Ami Shah, Neena Kapoor, Donald B. Kohn, Gay M. Crooks, and Robertson Parkman, Kathy Wilson, RN, and members of the BMT units at Childrens Hospital Los Angeles and Fairview-University of Minnesota Hospitals and Clinics for generously providing patient samples; and Roberta Nicklow, Cynthia Eide, Pamela Phillips, and Matthew Johnson for their assistance. R.A.K. is an Elizabeth Glaser Scientist of the Pediatric AIDS Foundation.
Submitted July 19, 2000; accepted October 31, 2000.
Supported by the General Clinical Research Center at Childrens Hospital Los Angeles, National Institutes of Health (NIH) grants M01 RR00043, R01 HL54729, and R21 HD37598, and the T.J. Martell Foundation (K.W.); NIH grants R01 AI 34495, 2 R37 HL56067, and P01 AI-35225, and the National Marrow Donor Program (B.R.B.); The Leukemia Association of North Central Texas (R.H.C.); and Leukemia and Lymphoma Society of America Translational Research Award 6540-00 (D.C.D.).
K.W. and B.R.B. contributed equally to this paper.
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Kenneth Weinberg, Division of Research Immunology/Bone Marrow Transplantation, Mailstop #62, Childrens Hospital Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027; e-mail: kweinberg{at}chla.usc.edu.
1. Parkman R, Weinberg K. Immunological reconstitution following hematopoietic stem cell transplantation. In: Thomas ED,Blume KG,Forman SJ, eds. Hematopoietic Cell Transplantation. 2nd ed. Oxford, England: Blackwell Science; 1999:704-711. 2. Ochs L, Shu XO, Miller J, et al. Late infections after allogeneic bone marrow transplantations: comparison of incidence in related and unrelated donor transplant recipients. Blood. 1995;86:13979-13986.
3.
Socié G, Stone JV, Wingard JR, et al.
Long-term survival and late deaths after allogeneic bone marrow transplantation. Late Effects Working Committee of the International Bone Marrow Transplant Registry.
N Engl J Med.
1999;341:14-21 4. Weinberg K, Annett G, Kashyap A, Lenarsky C, Forman SJ, Parkman R. The effect of thymic function on immunocompetence following bone marrow transplant. Biol Blood Marrow Transplant. 1995;1:18-23[Medline] [Order article via Infotrieve].
5.
Small TN, Papadopoulos EB, Boulad F, et al.
Comparison of immune reconstitution after unrelated and related T-cell-depleted bone marrow transplantation: effect of patient age and donor leukocyte infusions.
Blood.
1999;93:467-480
6.
Mackall CL, Fleisher TA, Brown MR, et al.
Age, thymopoiesis, and CD4+ T-cell regeneration after intensive chemotherapy.
N Engl J Med.
1995;332:143-149 7. Douek DC, McFarland RD, Keiser PH, et al. Changes in thymic function with age and during the treatment of HIV infection. Nature. 1998;396:690-695[CrossRef][Medline] [Order article via Infotrieve]. 8. Lapp WAS, Ghayur T, Mendes M, Seddik M, Seemayer TA. The functional and histological basis for graft-versus-host-induced immunosuppression. Immunol Rev. 1985;88:107-133[CrossRef][Medline] [Order article via Infotrieve]. 9. Seemayer TA, Lapp WS, Bolande RP. Thymic involution in murine graft-versus-host reaction: epithelial injury mimicking human thymic dysplasia. Am J Pathol. 1977;88:119-133[Abstract]. 10. Chung B, Barbara-Burnham L, Barsky L, Weinberg K. Thymic IL-7 production is radiosensitive and is related to thymic recovery after murine bone marrow transplant (BMT). Blood. 1998;92:2959a. 11. Smith KY, Valdez H, Landay A, et al. Thymic size and lymphocyte restoration in patients with human immunodeficiency virus infection after 48 weeks of zidovudine, lamivudine, and ritonavir therapy. J Infect Dis. 2000;181:141-147[CrossRef][Medline] [Order article via Infotrieve].
12.
Tough DF, Sprent J.
Turnover of naive- and memory-phenotype T-cells.
J Exp Med.
1994;179:1127-1135
13.
McLean A, Michie C.
In vivo estimates of division and death rates of human T lymphocytes.
Proc Natl Acad Sci U S A.
1995;92:3707-3711
14.
Soares MV, Borthwick NJ, Maini MK, Janossy G, Salmon M, Akbar AN.
IL-7-dependent extrathymic expansion of CD45RA+ T-cells enables preservation of a naive repertoire.
J Immunol.
1998;161:5909-5917 15. Picker L, Treer J, Ferguson-Darnell B, Collins P, Buck D, Terstappen L. Control of lymphocyte recirculation in man. J Immunol. 1993;150:1105-1121[Abstract]. 16. Young JL, Ramage JM, Gaston JS, Beverley PC. In vitro responses of human CD45R0brightRA- and CD45R0-RAbright T cell subsets and their relationship to memory and naive T cells. Eur J Immunol. 1997;27:2383-2390[Medline] [Order article via Infotrieve].
17.
Hamann D, Baars PA, Rep MH, et al.
Phenotypic and functional separation of memory and effector human CD8+ T-cells.
J Exp Med.
1997;186:1407-1418 18. Kong F-K, Chen C-L, Cooper M. Thymic function can be accurately monitored by the level of recent T cell emigrants in the circulation. Immunity. 1998;8:97-104[CrossRef][Medline] [Order article via Infotrieve]. 19. Santos GW, Tutschka PJ, Brookmeyer R, et al. Marrow transplantation for acute nonlymphocytic leukemia after treatment with busulfan and cyclophosphamide. N Engl J Med. 1983;309:1347-1353[Abstract].
20.
Blume KG, Forman SJ, O'Donnell MR, et al.
Total body irradiation and high-dose etoposide: a new preparatory regimen for bone marrow transplantation in patients with advanced hematologic malignancies.
Blood.
1987;69:1015-1020 21. Fefer A, Einstein AB, Thomas ED, et al. Bone-marrow transplantation for hematologic neoplasia in 16 patients with identical twins. N Engl J Med. 1974;290:1389-1393. 22. Wagner JE, Kernan NA, Steinbuch M, Broxmeyer HE, Gluckman E. Allogeneic sibling umbilical-cord-blood transplantation in children with malignant and non-malignant disease. Lancet. 1995;346:214-219[CrossRef][Medline] [Order article via Infotrieve].
23.
Wagner JE, Rosenthal J, Sweetman R, et al.
Successful transplantation of HLA-matched and HLA-mismatched umbilical cord blood from unrelated donors: analysis of engraftment and acute graft-versus-host disease.
Blood.
1996;88:795-802
24.
Rocha V, Wagner JE, Sobocinski KA, et al.
Graft-versus-host disease in children who have received a cord-blood or bone marrow transplant from an HLA-identical sibling. Eurocord and International Bone Marrow Transplant Registry Working Committee on Alternative Donor and Stem Cell Sources.
N Engl J Med.
2000;342:1846-1854
25.
Brown RA, Wolff SN, Fay JW, et al.
High-dose etoposide, cyclophosphamide, and total body irradiation with allogeneic bone marrow transplantation for patients with acute myeloid leukemia in untreated first relapse: a study by the North American Marrow Transplant Group.
Blood.
1995;85:1391-1395
26.
Storb R, Etzioni R, Anasetti C, et al.
Cyclophosphamide combined with antithymocyte globulin in preparation for allogeneic transplants in patients with aplastic anemia.
Blood.
1994;84:941-949 27. Glucksberg H, Storb R, Fefer A, et al. Clinical manifestations of graft-versus-host disease in human recipients of marrow from HL-A-matched sibling donors. Transplantation. 1974;18:295-304[Medline] [Order article via Infotrieve]. 28. Douek DC, Vescio RA, Betts MR, et al. Assessment of thymic output in adults after haematopoietic stem cell transplant and prediction of T-cell reconstitution. Lancet. 2000;355:1875-1881[CrossRef][Medline] [Order article via Infotrieve]. 29. Haynes BF, Hale LP, Weinhold KJ, et al. Analysis of the adult thymus in reconstitution of T lymphocytes in HIV-1 infection. J Clin Invest. 1999;103:453-460[Medline] [Order article via Infotrieve].
30.
Kornbluth M, You-Ten E, Desbarats J, Gamache S, Xenocostas A, Lapp WS.
T-cell subsets in the thymus of graft-versus-host immunosuppressed mice: sensitivity of the L3T4+Lyt-2
31.
Hess AD, Horwitz L, Beschorner WE, Santos GW.
Development of graft-vs.-host disease-like syndrome in cyclosporine-treated rats after syngeneic bone marrow transplantation, I: development of cytotoxic T lymphocytes with apparent polyclonal anti-Ia specificity, including autoreactivity.
J Exp Med.
1985;161:718-730
32.
Jenkins MK, Schwartz RH, Pardoll DM.
Effects of cyclosporine A on T-cell development and clonal deletion.
Science.
1988;241:1655-1658
33.
Zadeh HH, Goldschneider I.
Demonstration of large-scale migration of cortical thymocytes to peripheral lymphoid tissues in cyclosporin A-treated rats.
J Exp Med.
1993;178:285-293 34. You-Ten KE, Lapp WS. The role of endogenous glucocorticoids on host T-cell populations in the peripheral lymphoid organs of mice with graft-versus-host disease. Transplantation. 1996;61:76-83[CrossRef][Medline] [Order article via Infotrieve]. 35. Ghayur T, Seemayer TA, Xenocostas A, Lapp WS. Complete sequential regeneration of graft-vs.-host-induced severely dysplastic thymuses: implications for the pathogenesis of chronic graft-vs.-host disease. Am J Pathol. 1988;133:39-46[Abstract]. 36. Seddik M, Seemayer TA, Lapp WS. T-cell functional defect associated with thymic epithelial cell injury induced by a graft-versus-host reaction. Transplantation. 1980;29:61-66[Medline] [Order article via Infotrieve]. 37. Seddik M, Seemayer TA, Lapp WS. The graft-versus-host reaction and immune function, I: T helper cell immunodeficiency associated with graft-versus-host-induced thymic epithelial cell damage. Transplantation. 1984;37:281-286[Medline] [Order article via Infotrieve]. 38. Fukuzawa M, Via CS, Shearer GM. Defective thymic education of L3T4+ T helper cell function in graft-vs-host mice. J Immunol. 1988;141:430-439[Abstract]. 39. Fukuzawa M, Sharrow SO, Shearer GM. Effect of cyclosporin A on T-cell immunity, II: defective thymic education of CD4 T helper cell function in cyclosporin A-treated mice. Eur J Immunol. 1989;19:1147-1152[Medline] [Order article via Infotrieve].
40.
Fukushi N, Arase H, Wang B, et al.
Thymus: a direct target tissue in graft-versus-host reaction after allogeneic bone marrow transplantation that results in abrogation of induction of self-tolerance.
Proc Natl Acad Sci U S A.
1990;87:6301-6305 41. Hollander GA, Widmer B, Burakoff SJ. Loss of normal thymic repertoire selection and persistence of autoreactive T-cells in graft vs host disease. J Immunol. 1994;152:1609-1617[Abstract]. 42. van den Brink MR, Moore E, Ferrara JL, Burakoff SJ. Graft-versus-host-disease-associated thymic damage results in the appearance of T-cell clones with anti-host reactivity. Transplantation. 2000;69:446-449[CrossRef][Medline] [Order article via Infotrieve].
43.
Krenger W, Rossi S, Piali L, Hollander GA.
Thymic atrophy in murine acute graft-versus-host disease is effected by impaired cell cycle progression of host pro-T and pre-T cells.
Blood.
2000;96:347-354 44. Patel DD, Whichard LP, Radcliff G, Denning SM, Haynes BF. Characterization of human thymic epithelial cell surface antigens: phenotypic similarity of thymic epithelial cells to epidermal keratinocytes. J Clin Immunol. 1995;15:80-92[CrossRef][Medline] [Order article via Infotrieve]. 45. Beschorner WE, Hutchins GM, Elfenbein GJ, Santos GW. The thymus in patients with allogeneic bone marrow transplants. Am J Pathol. 1978;92:173-181[Abstract].
46.
Blazar BR, Taylor PA, Panoskaltsis-Mortari A, Sehgal S, Vallera DA.
In vivo inhibition of cytokine responsiveness and graft-versus-host disease mortality by rapamycin leads to a clinical-pathological syndrome discrete from that observed with cyclosporin A.
Blood.
1996;87:4001-4009
47.
Johnson BD, Becker EE, LaBelle JL, Truitt RL.
Role of immunoregulatory donor T-cells in suppression of graft-versus-host disease following donor leukocyte infusion therapy.
J Immunol.
1999;163:6479-6487
48.
Patel DD, Gooding ME, Parrott RE, Curtis KM, Haynes BF, Buckley RH.
Thymic function after hematopoietic stem-cell transplantation for the treatment of severe combined immunodeficiency.
N Engl J Med.
2000;342:1325-1332 49. Hollander GA, Wang B, Nichogiannopoulou A, et al. Developmental control point in induction of thymic cortex regulated by a subpopulation of prothymocytes. Nature. 1995;373:350353. 50. Blazar BR, Taylor PA, Noelle RJ, Vallera DA. CD4+ T-cells tolerized ex vivo to host alloantigen by anti-CD40 ligand (CD40L:CD154) antibody lose their graft-versus-host disease lethality capacity while retaining nominal antigen responses. J Clin Invest. 1998;102:473-482[Medline] [Order article via Infotrieve].
51.
Zeller JC, Panoskaltsis-Mortari A, Murphy WJ, et al.
Induction of CD4+ T-cell alloantigen-specific hyporesponsiveness by IL-10 and TGF-beta.
J Immunol.
1999;163:3684-3691
52.
Groux H, Bigler M, de Vries JE, Roncarolo MG.
Interleukin-10 induces a long-term antigen-specific anergic state in human CD4+ T-cells.
J Exp Med.
1996;184:19-29 53. Boussiotis VA, Freeman GJ, Taylor PA, et al. p27kip1 functions as an anergy factor inhibiting IL-2 transcription and expansion of human and murine alloreactive helper T lymphocytes in vitro and in vivo. Nat Med. 2000;6:290-297[CrossRef][Medline] [Order article via Infotrieve].
54.
Guinan EC, Boussiotis VA, Neuberg D, et al.
Transplantation of anergic histoincompatible bone marrow allografts.
N Engl J Med.
1999;340:1704-1714
55.
Bolotin E, Smogorzewska M, Smith S, Widmer M, Weinberg K.
Enhancement of thymopoiesis after bone marrow transplant by in vivo interleukin-7.
Blood.
1996;88:1887-1894 56. Sempowski G, Thomasch J, Gooding M, Hale L, Edwards L, Ciafaloni E, Sanders D, Massey J, Douek D, Koup R, Haynes B. Effect of thymectomy on peripheral T cell homeostasis. J Immunol. In press.
© 2001 by The American Society of Hematology.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
|
 |
|
  T. J. Fry Is a little GVHD a good thing? Blood, June 18, 2009; 113(25): 6274 - 6275. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Clave, M. Busson, C. Douay, R. Peffault de Latour, J. Berrou, C. Rabian, M. Carmagnat, V. Rocha, D. Charron, G. Socie, et al. Acute graft-versus-host disease transiently impairs thymic output in young patients after allogeneic hematopoietic stem cell transplantation Blood, June 18, 2009; 113(25): 6477 - 6484. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. J. Opiela, T. Koru-Sengul, and B. Adkins Murine neonatal recent thymic emigrants are phenotypically and functionally distinct from adult recent thymic emigrants Blood, May 28, 2009; 113(22): 5635 - 5643. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Neven, S. Leroy, H. Decaluwe, F. Le Deist, C. Picard, D. Moshous, N. Mahlaoui, M. Debre, J.-L. Casanova, L. Dal Cortivo, et al. Long-term outcome after hematopoietic stem cell transplantation of a single-center cohort of 90 patients with severe combined immunodeficiency Blood, April 23, 2009; 113(17): 4114 - 4124. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. De Leon-Luis, F. Gamez, P. Pintado, E. Antolin, R. Perez, L. Ortiz-Quintana, and J. Santolaya-Forgas Sonographic Measurements of the Thymus in Male and Female Fetuses J. Ultrasound Med., January 1, 2009; 28(1): 43 - 48. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. M. Williams, P. J. Lucas, C. V. Bare, J. Wang, Y.-W. Chu, E. Tayler, V. Kapoor, and R. E. Gress CCL25 increases thymopoiesis after androgen withdrawal Blood, October 15, 2008; 112(8): 3255 - 3263. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Vrisekoop, R. van Gent, A. B. de Boer, S. A. Otto, J. C. C. Borleffs, R. Steingrover, J. M. Prins, T. W. Kuijpers, T. F. W. Wolfs, S. P. M. Geelen, et al. Restoration of the CD4 T Cell Compartment after Long-Term Highly Active Antiretroviral Therapy without Phenotypical Signs of Accelerated Immunological Aging J. Immunol., July 15, 2008; 181(2): 1573 - 1581. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. M. Kelly, S. L. Highfill, A. Panoskaltsis-Mortari, P. A. Taylor, R. L. Boyd, G. A. Hollander, and B. R. Blazar Keratinocyte growth factor and androgen blockade work in concert to protect against conditioning regimen-induced thymic epithelial damage and enhance T-cell reconstitution after murine bone marrow transplantation Blood, June 15, 2008; 111(12): 5734 - 5744. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. S. Sutherland, L. Spyroglou, J. L. Muirhead, T. S. Heng, A. Prieto-Hinojosa, H. M. Prince, A. P. Chidgey, A. P. Schwarer, and R. L. Boyd Enhanced Immune System Regeneration in Humans Following Allogeneic or Autologous Hemopoietic Stem Cell Transplantation by Temporary Sex Steroid Blockade Clin. Cancer Res., February 15, 2008; 14(4): 1138 - 1149. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Castermans, F. Baron, E. Willems, N. Schaaf-Lafontaine, N. Meuris, A. Gothot, J.-F. Vanbellighen, C. Herens, L. Seidel, V. Geenen, et al. Evidence for neo-generation of T cells by the thymus after non-myeloablative conditioning Haematologica, February 1, 2008; 93(2): 240 - 247. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. H. Nguyen, S. Shashidhar, D. S. Chang, L. Ho, N. Kambham, M. Bachmann, J. M. Brown, and R. S. Negrin The impact of regulatory T cells on T-cell immunity following hematopoietic cell transplantation Blood, January 15, 2008; 111(2): 945 - 953. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. V. Komanduri, L. S. St. John, M. de Lima, J. McMannis, S. Rosinski, I. McNiece, S. G. Bryan, I. Kaur, S. Martin, E. D. Wieder, et al. Delayed immune reconstitution after cord blood transplantation is characterized by impaired thymopoiesis and late memory T-cell skewing Blood, December 15, 2007; 110(13): 4543 - 4551. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Chung, E. P. Dudl, D. Min, L. Barsky, N. Smiley, and K. I. Weinberg Prevention of graft-versus-host disease by anti IL-7R{alpha} antibody Blood, October 15, 2007; 110(8): 2803 - 2810. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Creamer, C. L. Martyn-Simmons, G. Osborne, M. Kenyon, J. R. Salisbury, S. Devereux, A. Pagliuca, A. Y. Ho, G. J. Mufti, and A. W. P. du Vivier Eczematoid Graft-vs-Host Disease: A Novel Form of Chronic Cutaneous Graft-vs-Host Disease and Its Response to Psoralen UV-A Therapy Arch Dermatol, September 1, 2007; 143(9): 1157 - 1162. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Zhang, E. Hexner, D. Frank, and S. G. Emerson CD4+ T Cells Generated De Novo from Donor Hemopoietic Stem Cells Mediate the Evolution from Acute to Chronic Graft-versus-Host Disease J. Immunol., September 1, 2007; 179(5): 3305 - 3314. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Smith-Berdan, D. Gille, I. L. Weissman, and J. L. Christensen Reversal of autoimmune disease in lupus-prone New Zealand black/New Zealand white mice by nonmyeloablative transplantation of purified allogeneic hematopoietic stem cells Blood, August 15, 2007; 110(4): 1370 - 1378. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. B. Kohn Gene therapy as salvage Blood, July 1, 2007; 110(1): 4 - 4. [Full Text] [PDF]
|
|
|
|
|
|
J. Gorski, X. Chen, M. Gendelman, M. Yassai, A. Krueger, E. Tivol, B. Logan, R. Komorowski, S. Vodanovic-Jankovic, and W. R. Drobyski Homeostatic expansion and repertoire regeneration of donor T cells during graft versus host disease is constrained by the host environment Blood, June 15, 2007; 109(12): 5502 - 5510. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Cavazzana-Calvo, F. Carlier, F. Le Deist, E. Morillon, P. Taupin, D. Gautier, I. Radford-Weiss, S. Caillat-Zucman, B. Neven, S. Blanche, et al. Long-term T-cell reconstitution after hematopoietic stem-cell transplantation in primary T-cell-immunodeficient patients is associated with myeloid chimerism and possibly the primary disease phenotype Blood, May 15, 2007; 109(10): 4575 - 4581. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. I. Weinberg ProTECtion from posttransplantation immune deficiency? Blood, May 1, 2007; 109(9): 3617 - 3618. [Full Text] [PDF]
|
|
|
|
|
|
M. M. Hauri-Hohl, M. P. Keller, J. Gill, K. Hafen, E. Pachlatko, T. Boulay, A. Peter, G. A. Hollander, and W. Krenger Donor T-cell alloreactivity against host thymic epithelium limits T-cell development after bone marrow transplantation Blood, May 1, 2007; 109(9): 4080 - 4088. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. W. Rossi, L. T. Jeker, T. Ueno, S. Kuse, M. P. Keller, S. Zuklys, A. V. Gudkov, Y. Takahama, W. Krenger, B. R. Blazar, et al. Keratinocyte growth factor (KGF) enhances postnatal T-cell development via enhancements in proliferation and function of thymic epithelial cells Blood, May 1, 2007; 109(9): 3803 - 3811. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E.-J. Wils, E. Braakman, G. M. G. M. Verjans, E. J. C. Rombouts, A. E. C. Broers, H. G. M. Niesters, G. Wagemaker, F. J. T. Staal, B. Lowenberg, H. Spits, et al. Flt3 Ligand Expands Lymphoid Progenitors Prior to Recovery of Thymopoiesis and Accelerates T Cell Reconstitution after Bone Marrow Transplantation J. Immunol., March 15, 2007; 178(6): 3551 - 3557. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Sakoda, D. Hashimoto, S. Asakura, K. Takeuchi, M. Harada, M. Tanimoto, and T. Teshima Donor-derived thymic-dependent T cells cause chronic graft-versus-host disease Blood, February 15, 2007; 109(4): 1756 - 1764. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. R. Blazar, D. J. Weisdorf, T. DeFor, A. Goldman, T. Braun, S. Silver, and J. L. M. Ferrara Phase 1/2 randomized, placebo-control trial of palifermin to prevent graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT) Blood, November 1, 2006; 108(9): 3216 - 3222. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. Borghans, R. G. Bredius, M. D. Hazenberg, H. Roelofs, E. C. Jol-van der Zijde, J. Heidt, S. A. Otto, T. W. Kuijpers, W. E. Fibbe, J. M. Vossen, et al. Early determinants of long-term T-cell reconstitution after hematopoietic stem cell transplantation for severe combined immunodeficiency Blood, July 15, 2006; 108(2): 763 - 769. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. S. T.-D. Ravin, D. R. Kennedy, N. Naumann, J. S. Kennedy, U. Choi, B. J. Hartnett, G. F. Linton, N. L. Whiting-Theobald, P. F. Moore, W. Vernau, et al. Correction of canine X-linked severe combined immunodeficiency by in vivo retroviral gene therapy Blood, April 15, 2006; 107(8): 3091 - 3097. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Z. Pavletic, S. L. Carter, N. A. Kernan, J. Henslee-Downey, A. M. Mendizabal, E. Papadopoulos, R. Gingrich, J. Casper, S. Yanovich, D. Weisdorf, et al. Influence of T-cell depletion on chronic graft-versus-host disease: results of a multicenter randomized trial in unrelated marrow donor transplantation Blood, November 1, 2005; 106(9): 3308 - 3313. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. J. Lee New approaches for preventing and treating chronic graft-versus-host disease Blood, June 1, 2005; 105(11): 4200 - 4206. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Clave, V. Rocha, K. Talvensaari, M. Busson, C. Douay, M.-L. Appert, C. Rabian, M. Carmagnat, F. Garnier, A. Filion, et al. Prognostic value of pretransplantation host thymic function in HLA-identical sibling hematopoietic stem cell transplantation Blood, March 15, 2005; 105(6): 2608 - 2613. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. J. Workman and D. A. A. Vignali Negative Regulation of T Cell Homeostasis by Lymphocyte Activation Gene-3 (CD223) J. Immunol., January 15, 2005; 174(2): 688 - 695. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Chen, R. Barfield, E. Benaim, W. Leung, J. Knowles, D. Lawrence, M. Otto, S. A. Shurtleff, G. A. M. Neale, F. G. Behm, et al. Prediction of T-cell reconstitution by assessment of T-cell receptor excision circle before allogeneic hematopoietic stem cell transplantation in pediatric patients Blood, January 15, 2005; 105(2): 886 - 893. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C Kayser, F L Alberto, N P da Silva, and L E. Andrade Decreased number of T cells bearing TCR rearrangement excision circles (TREC) in active recent onset systemic lupus erythematosus Lupus, December 1, 2004; 13(12): 906 - 911. [Abstract] [PDF]
|
|
|
|
 |
|
 T. Iwasaki Recent Advances in the Treatment of Graft-Versus-Host Disease Clin. Med. Res., November 1, 2004; 2(4): 243 - 252. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. J. Fry, M. Sinha, M. Milliron, Y.-W. Chu, V. Kapoor, R. E. Gress, E. Thomas, and C. L. Mackall Flt3 ligand enhances thymic-dependent and thymic-independent immune reconstitution Blood, November 1, 2004; 104(9): 2794 - 2800. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Miura, C. J. Thoburn, E. C. Bright, M. L. Phelps, T. Shin, E. C. Matsui, W. H. Matsui, S. Arai, E. J. Fuchs, G. B. Vogelsang, et al. Association of Foxp3 regulatory gene expression with graft-versus-host disease Blood, October 1, 2004; 104(7): 2187 - 2193. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Imado, T. Iwasaki, Y. Kataoka, T. Kuroiwa, H. Hara, J. Fujimoto, and H. Sano Hepatocyte growth factor preserves graft-versus-leukemia effect and T-cell reconstitution after marrow transplantation Blood, September 1, 2004; 104(5): 1542 - 1549. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Krenger, H. Schmidlin, G. Cavadini, and G. A. Hollander On the Relevance of TCR Rearrangement Circles as Molecular Markers for Thymic Output during Experimental Graft-versus-Host Disease J. Immunol., June 15, 2004; 172(12): 7359 - 7367. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Yamashita, U. Choi, P. C. Woltz, S. F. Foster, M. C. Sneller, F. T. Hakim, D. H. Fowler, M. R. Bishop, S. Z. Pavletic, M. Tamari, et al. Severe chronic graft-versus-host disease is characterized by a preponderance of CD4+ effector memory cells relative to central memory cells Blood, May 15, 2004; 103(10): 3986 - 3988. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. J. Clark, R. Gregg, K. Piper, D. Dunnion, L. Freeman, M. Griffiths, G. Begum, P. Mahendra, C. Craddock, P. Moss, et al. Chronic graft-versus-host disease is associated with increased numbers of peripheral blood CD4+CD25high regulatory T cells Blood, March 15, 2004; 103(6): 2410 - 2416. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Gendelman, T. Hecht, B. Logan, S. Vodanovic-Jankovic, R. Komorowski, and W. R. Drobyski Host Conditioning Is a Primary Determinant in Modulating the Effect of IL-7 on Murine Graft-versus-Host Disease J. Immunol., March 1, 2004; 172(5): 3328 - 3336. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. J. Chao, S. G. Emerson, and K. I. Weinberg Stem Cell Transplantation (Cord Blood Transplants) Hematology, January 1, 2004; 2004(1): 354 - 371. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-F. Poulin, M. Sylvestre, P. Champagne, M.-L. Dion, N. Kettaf, A. Dumont, M. Lainesse, P. Fontaine, D.-C. Roy, C. Perreault, et al. Evidence for adequate thymic function but impaired naive T-cell survival following allogeneic hematopoietic stem cell transplantation in the absence of chronic graft-versus-host disease Blood, December 15, 2003; 102(13): 4600 - 4607. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. K. Gandhi, M. R. Wills, G. Okecha, E. K. Day, R. Hicks, R. E. Marcus, J. G. P. Sissons, and A. J. Carmichael Late diversification in the clonal composition of human cytomegalovirus-specific CD8+ T cells following allogeneic hemopoietic stem cell transplantation Blood, November 1, 2003; 102(9): 3427 - 3438. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Bachar-Lustig, S. Reich-Zeliger, and Y. Reisner Anti-third-party veto CTLs overcome rejection of hematopoietic allografts: synergism with rapamycin and BM cell dose Blood, September 15, 2003; 102(6): 1943 - 1950. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. E. C. Broers, S. J. Posthumus-van Sluijs, H. Spits, B. van der Holt, B. Lowenberg, E. Braakman, and J. J. Cornelissen Interleukin-7 improves T-cell recovery after experimental T-cell-depleted bone marrow transplantation in T-cell-deficient mice by strong expansion of recent thymic emigrants Blood, August 15, 2003; 102(4): 1534 - 1540. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Arber, A. BitMansour, T. E. Sparer, J. P. Higgins, E. S. Mocarski, I. L. Weissman, J. A. Shizuru, and J. M. Y. Brown Common lymphoid progenitors rapidly engraft and protect against lethal murine cytomegalovirus infection after hematopoietic stem cell transplantation Blood, July 15, 2003; 102(2): 421 - 428. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Orsini, R. Bellucci, E. P. Alyea, R. Schlossman, C. Canning, S. McLaughlin, P. Ghia, K. C. Anderson, and J. Ritz Expansion of Tumor-specific CD8+ T Cell Clones in Patients with Relapsed Myeloma after Donor Lymphocyte Infusion Cancer Res., May 15, 2003; 63(10): 2561 - 2568. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Sarzotti, D. D. Patel, X. Li, D. A. Ozaki, S. Cao, S. Langdon, R. E. Parrott, K. Coyne, and R. H. Buckley T Cell Repertoire Development in Humans with SCID After Nonablative Allogeneic Marrow Transplantation J. Immunol., March 1, 2003; 170(5): 2711 - 2718. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Malphettes, G. Carcelain, P. Saint-Mezard, V. Leblond, H. K. Altes, J.-P. Marolleau, P. Debre, J.-C. Brouet, J.-P. Fermand, and B. Autran Evidence for naive T-cell repopulation despite thymus irradiation after autologous transplantation in adults with multiple myeloma: role of ex vivo CD34+ selection and age Blood, March 1, 2003; 101(5): 1891 - 1897. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Dainiak, J. K. Waselenko, J. O. Armitage, T. J. MacVittie, and A. M. Farese The Hematologist and Radiation Casualties Hematology, January 1, 2003; 2003(1): 473 - 496. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. L. Sinha, T. J. Fry, D. H. Fowler, G. Miller, and C. L. Mackall Interleukin 7 worsens graft-versus-host disease Blood, September 18, 2002; 100(7): 2642 - 2649. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. R. Lewin, G. Heller, L. Zhang, E. Rodrigues, E. Skulsky, M. R. M. van den Brink, T. N. Small, N. A. Kernan, R. J. O'Reilly, D. D. Ho, et al. Direct evidence for new T-cell generation by patients after either T-cell-depleted or unmodified allogeneic hematopoietic stem cell transplantations Blood, August 28, 2002; 100(6): 2235 - 2242. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Eyrich, T. Croner, C. Leiler, P. Lang, P. Bader, T. Klingebiel, D. Niethammer, and P. G. Schlegel Distinct contributions of CD4+ and CD8+ naive and memory T-cell subsets to overall T-cell-receptor repertoire complexity following transplantation of T-cell-depleted CD34-selected hematopoietic progenitor cells from unrelated donors Blood, August 13, 2002; 100(5): 1915 - 1918. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Rossi, B. R. Blazar, C. L. Farrell, D. M. Danilenko, D. L. Lacey, K. I. Weinberg, W. Krenger, and G. A. Hollander Keratinocyte growth factor preserves normal thymopoiesis and thymic microenvironment during experimental graft-versus-host disease Blood, June 28, 2002; 100(2): 682 - 691. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Bellucci, E. P. Alyea, E. Weller, A. Chillemi, E. Hochberg, C. J. Wu, C. Canning, R. Schlossman, R. J. Soiffer, K. C. Anderson, et al. Immunologic effects of prophylactic donor lymphocyte infusion after allogeneic marrow transplantation for multiple myeloma Blood, May 29, 2002; 99(12): 4610 - 4617. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Ye and D. E. Kirschner Reevaluation of T Cell Receptor Excision Circles as a Measure of Human Recent Thymic Emigrants J. Immunol., May 15, 2002; 168(10): 4968 - 4979. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. D. Hazenberg, S. A. Otto, E. S. de Pauw, H. Roelofs, W. E. Fibbe, D. Hamann, and F. Miedema T-cell receptor excision circle and T-cell dynamics after allogeneic stem cell transplantation are related to clinical events Blood, May 1, 2002; 99(9): 3449 - 3453. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Talvensaari, E. Clave, C. Douay, C. Rabian, L. Garderet, M. Busson, F. Garnier, D. Douek, E. Gluckman, D. Charron, et al. A broad T-cell repertoire diversity and an efficient thymic function indicate a favorable long-term immune reconstitution after cord blood stem cell transplantation Blood, February 15, 2002; 99(4): 1458 - 1464. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Chakraverty, K. Peggs, R. Chopra, D. W. Milligan, P. D. Kottaridis, S. Verfuerth, J. Geary, D. Thuraisundaram, K. Branson, S. Chakrabarti, et al. Limiting transplantation-related mortality following unrelated donor stem cell transplantation by using a nonmyeloablative conditioning regimen Blood, February 1, 2002; 99(3): 1071 - 1078. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. R. Wingard, G. B. Vogelsang, and H. J. Deeg Stem Cell Transplantation: Supportive Care and Long-Term Complications Hematology, January 1, 2002; 2002(1): 422 - 444. [Abstract] [Full Text]
|
|
|
|
|
|
J. Storek, A. Joseph, G. Espino, M. A. Dawson, D. C. Douek, K. M. Sullivan, M. E. D. Flowers, P. Martin, G. Mathioudakis, R. A. Nash, et al. Immunity of patients surviving 20 to 30 years after allogeneic or syngeneic bone marrow transplantation Blood, December 15, 2001; 98(13): 3505 - 3512. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. C. Douek, M. R. Betts, B. J. Hill, S. J. Little, R. Lempicki, J. A. Metcalf, J. Casazza, C. Yoder, J. W. Adelsberger, R. A. Stevens, et al. Evidence for Increased T Cell Turnover and Decreased Thymic Output in HIV Infection J. Immunol., December 1, 2001; 167(11): 6663 - 6668. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Chung, L. Barbara-Burnham, L. Barsky, and K. Weinberg Radiosensitivity of thymic interleukin-7 production and thymopoiesis after bone marrow transplantation Blood, September 1, 2001; 98(5): 1601 - 1606. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. P. Hochberg, A. C. Chillemi, C. J. Wu, D. Neuberg, C. Canning, K. Hartman, E. P. Alyea, R. J. Soiffer, S. A. Kalams, and J. Ritz Quantitation of T-cell neogenesis in vivo after allogeneic bone marrow transplantation in adults Blood, August 15, 2001; 98(4): 1116 - 1121. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
 |
|||||||
 |
 |
 |
 |
 |
 |
 |
 |
||
| Copyright © 2001 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
Top
Abstract
Introduction
) and CD8+ (
)
T-cell TREC levels are shown for a cross-section of patients
through 25 years of age with no history of GVHD. (B) Patients
through 25 years of age with chronic GVHD. (C) Patients
through 25 years of age with a history of GVHD. (D) A
composite box plot for TREC levels is shown for all 3 groups. The top,
bottom, and line through the middle of the box correspond to the 75th,
25th, and 50th percentile (median) respectively. The whiskers on the
bottom and top extend from the 10th percentile and top 90th percentile,
respectively. (E) Individual CD4+ (closed symbols) and
CD8+ (open symbols) T-cell TREC levels are shown for a
cross-section of patients older than 25 years of age with no history of
GVHD (squares), with chronic GVHD (triangles), and with a history of
GVHD (circles). Normal range of TREC levels for individuals of
ages in groups studied are shown lying between the
dashed lines.
