Immunologic characterization of chronic lymphocytic leukemia cells

Immunologic characterization of the neoplastic cells in the circulation of patients with CLL suggests these cells show significant differences in membrane characteristics from normal B lymphocytes. Although the leukemic cells bear a homogenous membrane‐associated immunoglobulin, they also react with an anti‐human T cell serum. In all patients studied, 60–90% of the cells were stained by this antiserum. This suggests that the leukemic cells share antigenic determinants with T lymphocytes. CLL cells, unlike normal B cells, showed a marked increase in mouse‐complement receptors. No increase in receptors for guinea pig complement was observed in the leukemic cells. The population of SIg‐bearing lymphocytes was significantly greater than that of complement‐receptor bearing lymphocytes. The total number of E‐rosetting cells was increased in all CLL patients. Mitogenic responses of the leukemic cells were depressed and delayed. These results suggest that neoplastic lymphocytes cannot be classified as T‐ or B‐derived on the basis of criteria used to define normal lymphocytes.