Crossreaction of monoclonal anti-T-cell antibodies: implications for classifying B-cell leukemias.

Cell samples from 62 patients with B-cell leukemias (33 CLL, 8 IC, 6 PLL, 4 HCL, 2 ALL and 9 other NHL) were tested with a series of monoclonal antibodies (A50, T101, Lyt2, Leu 1, M203) directed against T cells and shown to crossreact with B-CLL. The results demonstrate a heterogeneity of B-cell leukemias as all typical cases of CLL were reactive whereas most other cases were negative. Using the fluorescence-activated cell sorter, a somewhat stronger reaction was seen in early or benign cases of CLL, compared to advanced cases. All B-cell leukemias tested expressed the Ia antigen.