Response patterns of hairy cell leukemia to B-cell mitogens and growth
factors
BA Barut, MK Cochran, C O'Hara and KC Anderson
Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA
02115.
The effect of mitogens and/or recombinant B-cell growth factors (M/GFs) on
the in vitro growth of hairy cells was examined. Tumor cells were isolated
from the spleens of four patients with hairy cell leukemia (HCL) by
Ficoll-Hypaque sedimentation and E-rosetting. Enrichment for tumor cells
was confirmed with intracytoplasmic immunoglobulin (Ig) staining, tartrate
resistant acid phosphatase (TRAP) staining, and staining using monoclonal
antibodies (MoAbs) directed at B, T, myeloid, and monocytoid antigens (Ags)
in indirect immunofluorescence assays. Tumor cells were B1(CD20)+ B2(CD21)-
B4(CD19)+ IL-2R(CD25)+ PCA-1 +/- TRAP+. HCLs neither synthesized DNA nor
secreted Ig in response to culture with granulocyte-macrophage
colony-stimulating factor (GM-CSF), interleukin-1 alpha (IL-1 alpha), IL-1
beta, IL-2, IL-3, IL-4, IL-5, or IL-6. However, a proliferative response
(stimulation index greater than or equal to 3.0) without Ig secretion was
triggered in HCLs by mitogens or combinations of GFs. Specifically, DNA
synthesis was induced at 3 days in three of four HCL samples cultured with
Staphylococcus aureus Cowan A (SAC) or the combination of phorbol ester
(TPA) and the calcium ionophore A 23187 (Ca2+); DNA synthesis was triggered
later (day 7) by tumor necrosis factor (TNF) or by IL-4 and IL-5. In
contrast, the fourth patient, a nonresponder to SAC or TPA/Ca2+,
demonstrated increased DNA synthesis at day 3 when cocultured with IL-4 and
IL-5. Both autoradiography and staining with antibromodeoxyuridine (BrdU)
MoAb conjugated to fluorescein confirmed DNA synthesis by only a minority
(5% to 23%) of tumor cells within each patient. Dual staining confirmed
that responsive cells were both BrdU+ and TRAP+. DNA synthesis induced by
TPA/Ca2+ was blocked specifically by anti-IL-6 Ab; in contrast, the HCL
proliferative response to SAC, TNF, or IL-4 and IL- 5 was not inhibited by
anti-IL-6 Ab. alpha-Interferon inhibited the response to TPA/Ca2+, TNF, or
IL-4 and IL-5 without any effect on response to SAC. Finally,
peroxidase-antiperoxidase staining demonstrated that HCLs are induced by
TPA/Ca2+, but not by SAC, to produce intracytoplasmic IL-6. These data
demonstrate IL-4, IL-5, and IL-6 mediated DNA synthesis by HCLs in vitro
and suggest a possible in vivo role for these growth factors in the
pathophysiology of HCL.
Volume 76,
Issue 10,
pp. 2091-2097,
11/15/1990
Copyright © 1990 by The American Society of Hematology
