HETEROGENEOUS PROLIFERATIVE EFFECT OF TUMOR-NECROSIS-FACTOR-ALPHA ANDLYMPHOTOXIN ON MITOGEN-ACTIVATED B-CELLS FROM B-CHRONIC LYMPHOCYTIC-LEUKEMIA

The proliferative effect of tumor necrosis factor-alpha (TNF-alpha) an d lymphotoxin on B cells from patients with B-chronic lymphocytic leuk emia (B-CLL) was studied. Fresh purified B-CLL lymphocytes showed no p roliferative response to either recombinant (r) TNF-alpha or r-lymphot oxin. However, after ''in vitro'' activation of B-CLL lymphocytes for 2 days with Staphylococcus aureus Cowan 1 (SAC), four of seven patient s showed enhanced blastogenic response in the presence of either rTNF- alpha or r-lymphotoxin. We also found that the proliferative response of SAC-activated B-CLL lymphocytes to the two cytokines was independen t of that found in the presence of interleukin-2. These results demons trate that TNF-alpha and lymphotoxin can heterogeneously support the p roliferation of in vitro activated B cells from B-CLL patients and may reflect the biological heterogeneity of B-CLL disease.