Chronic Lymphocytic Leukemia B Cells Are Resistant to the Apoptotic Effects of Transforming Growth Factor-b

Chronic lymphocytic leukemia (CLL) is the most common apoptosis, CLL B-cell proliferation was variably inhibited leukemia of the western world and is characterized by a with addition of TGF-b. In vitro addition of IL-4, previously slowly progressing accumulation of clonal CD5 B cells. Our reported to promote CLL B-cell survival, dramatically relaboratory has investigated the role of transforming growth duced spontaneous apoptosis of CLL B cells compared with factor-b (TGF-b) and interleukin-4 (IL-4) in the pathogenesis normal B cells. CLL B-cell expression of IL-4 receptors was of B-cell expansion in CLL. In vitro addition of TGF-b did not increased compared to normal B cells. Thus, our results increase spontaneous apoptosis of B cells from most CLL show aberrant apoptotic responses of CLL B cells to TGF-b patients, as determined using the TUNEL method, compared and IL-4, perhaps contributing to the relative expansion of with a twofold increase observed in cultures of normal B the neoplastic clone. cells. There was similar expression of TGF-b type II receptors q 1997 by The American Society of Hematology. on both CLL B cells and normal B cells. In contrast to