THE EFFECT OF CYTOKINES ON CULTURED MONONUCLEAR-CELLS FROM PATIENTS WITH B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA

In the past 5 years a number of cytokines have been identified that co ntrol B cell development, proliferation, and maturation. The role of s uch cytokines in the evolution, pathophysiology, and treatment of B ce ll malignancies is an area of great interest. The in vitro response of freshly isolated peripheral blood mononuclear cells from patients wit h B cell chronic lymphocytic leukemia (B-CLL) and a high white cell co unt, to four cytokines, IFN-alpha, IFN-gamma, IL-2 and TNF, was studie d. No culture condition or cytokine resulted in a significant increase in cell number over 4 days, cells survived better in autologous serum than in heat inactivated foetal calf serum, and a small but significa nt increase in blast cells was seen when the cells were cultured in IL -2. There was a discrepancy between uptake of thymidine and increase i n cell number which can be explained by the low labelling index of the se cultures and the fact that cells can incorporate [H-3]-thymidine wi thout going into mitosis. The majority of cultures produced biological ly active TNF at levels ranging from 1 to 40 pg/ml. In IFN-alpha treat ed cultures TNF levels were decreased. Cultures contained biologically active IL-6 at levels ranging from 2 to 2800 U/ml. IL-6 production wa s not influenced by other cytokines. Thirteen of 28 patients had detec table IL-6 in their serum, but in cells lysed no more than 2 h after r emoval from the patient, message for IL-6 could not be detected by Nor thern blotting. Cells also failed to express IL-1beta mRNA but seven o f eight patients had low levels of TNF message. Preliminary data using in situ hybridization techniques revealed that whilst no mRNA for IL- 6 was detected, TNF and IL-1beta mRNA were detected in a minority of m ononuclear cells.