Blood, 1 March 2001, Vol. 97, No. 5, pp. 1153-1153
Viral load monitoring in transplant recipients
Stevens et al (page 1165) provide further evidence linking a
high-circulating Epstein Barr viral load with the development of
posttransplantation lymphoproliferative disorder (PTLD). Several prior
reports have identified increased EBV load, as determined in blood
lymphocytes, serum, or liver biopsy specimens, at or prior to the time
of clinical presentation with PTLD. The present study finds that an
elevated whole-blood EBV load can precede the clinical diagnosis and
that frequent monitoring is necessary as changes can occur rapidly. An
elevated EBV load may be indicative of overimmunosuppression.
Adjustments in immunosuppressive dosing or other early interventions to
lower viral load might therefore forestall the development of clinical
PTLD in monitored patients.
Several questions remain to be answered before proceeding to clinical
trials of early intervention, particularly in low-risk transplant
recipients. The best assay method, sampling frequency, threshold
values, and the effect of antiviral therapy on serum or lymphocyte
viral load determinations all need to be elucidated. Of particular
concern is the problem of false positive results, as exemplified in the
current study, where such a result was found in 2 of 8 control
patients. The challenge will be to define a clinical test that is
specific enough to justify an intervention that may threaten graft or
patient survival in settings where the risk of PTLD is low. Recent
progress suggests that reliable, routine monitoring of EBV load in
allograft recipients should be feasible and raises the hope that doing
so may prevent this frequently fatal complication of transplantation.
Lode J. Swinnen
Loyola University Chicago
