Monoclonal antibody-defined B-cell, T-cell and myelomonocytic antigens and other surface determinants on leukemic B cells of chronic lymphocytic leukemia.

CLL B cells were reactive with monoclonal B-cell antibody (Leu-10) in all patients tested or with monoclonal and heterologous antibodies to Ia-like antigens in all but one patient tested whereas these cells were nonreactive to monoclonal and heterologous antibodies to the cALL antigen in all 34 patients tested. Unexpectedly, of a total of 35 patients with B-CLL, we observed reactivity with monoclonal pan-T antibodies Leu-1, T-101, and OKT-1 (specific for a 65-67,000 dalton surface antigen) in 25 (93%) of 27 patients, in 14 (88%) of 16 patients and in 18 (78%) of 23 patients studied, respectively. Leukemic B cells were reactive with OKT-3 (19,000 dalton) pan-T antibody in 10 (56%) of 18 patients or with Leu-4 (28,000 dalton) pan-T antibody in only 2 (12%) of 17 patients studied. Sheep erythrocyte-rosetting T cells ranged from 0 to 24%. However, a majority of cells (39-100%) reacted with OKT-11 (E-receptor) in 8 (44%) of 18 patients but with Leu-5 (E-receptors) in only 2 (22%) of 9 patients studied. Helper OKT-4 and suppressor OKT-5/8 antibodies were reactive with leukemic B cells in 4 (29%) of 14 patients and in 7 (47%) of 15 patients studied. In contrast, the leukemic B cells from all but one of 22 patients did not react with either helper Leu-3 or suppressor Leu-2 antibody. Unexpectedly, leukemic B cells were also found to be reactive with myeloid or myelomonocytic antibodies (OKM-1 and MCS-1) in 9 (50%) of 18 patients and in 2 (17%) of 12 patients tested. These data suggest that subset of patients with B-CLL demonstrate expression of multiple T and/or myelomonocytic antigens on their leukemic cell populations. Expression of these determinants may reflect biological or clinical significance in CLL.