RAPID COMMUNICATION Interleukin-4 Induces Programmed Cell Death (Apoptosis) in Cases of High-Risk Acute Lymphoblastic Leukemia

We investigated the effects of interleukin-4 (11-4) on the survival of leukemic and normal B-cell progenitors cultured on bone marrow stroma. IL-4 (at 100 U/mL) was cytotoxic in 16 of 21 cases of B-lineage acute lymphoblastic leukemia, causing reductions in CD19’ cell numbers that ranged from 50% to greater than 99% (median 83.5%) of those in parallel cultures not exposed to the cytokine. All nine cases with the t(9;22)(q34;qll) or the t(4;ll)(q21;q23), chromosomal features that are often associated with multidrug resistance and a fatal outcome, were susceptible to IL-4 toxicity. IL-4 cytotoxicity resulted from induction of programmed cell death (apoptoris); there was no evidence of cell killing mediated by T, natural killer, or stromal cells. IL-4 cytotoxicity