ABNORMAL RESPONSE TO IL-5 IN B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA

In B-cell chronic lymphocytic leukemia, neoplastic B-lymphocytes are a rrested in development. Since interleukins are essential for B-cell di fferentiation, we examined whether B-CLL cells were capable of respond ing normally to interleukins. Purified B-lymphocytes from B-CLL patien ts and controls were compared for their ability to proliferate and dif ferentiate after stimulation with MCAT or SAC plus rhIL-2 or rhIL-5. W hen rhIL-5 was added to MCAT-stimulated cells, 8 of 10 controls showed a substantial increase in IgM production, compared with only 1 of 10 B-CLL patients. Lack of IL-5 responsiveness could provide insight into the arrested B-lymphocyte development of some B-CLL patients.