Monoclonal antibody studies in B-cell chronic lymphocytic leukemia and allied disorders†

Lymphocytes from 48 patients with B-cell chronic lymphocytic leukemia (B-CLL) and allied disorders were examined with a panel of monoclonal antibodies and conventional surface marker techniques. Surface immunoglobulin (SIg) and 1a-like antigen were regularly present on B-CLL cells. In addition, 24 of 32 specimens reacted with OKT1, a monoclonal antibody which detects both peripheral and thymic T cells, but reactivity was not observed with anti-T-cell monoclonal antibodies of more restricted specificity (OKT3, OKT4, OKT6, OKT8 or OKT11). Eighteen of 20 samples in which only SIgM was detected were OKT1 –positive, while all 4 with only SIgG were OKT1—negative. Cells from patients with hairy cell leukemia were unreactive with OKT1, but resembled B-CLL lymphocytes in the presence of clonal SIg and 1a-like antigen. Neoplastic plasma cells lacked 1a-like antigen and frequently SIg (2 of 5), but cytoplasmic immunoglobulin was present, cells reacted with OKT 10 (replicating lymphoid cells) and 2 of 5 with OKT9 (transferrin receptor) as well. Cutaneous T-cell lymphoma samples were reactive with the anti-T-cell monoclonal antibodies OKT1, OKT3 and OKT4 even when the sheep cell receptor could not be detected. Monoclonal antibodies can provide more certain diagnosis and superior resolution of cell lineage in these disorders than is possible by morphology alone.