Immunologic studies in chronic lymphocytic leukemia: defective stimulation of T-cell proliferation in autologous mixed lymphocyte culture.

Peripheral blood leukocytes from untreated patients with chronic lymphocytic leukemia (CLL) and normal age- and sex-matched control individuals were tested for the ability to respond with increased DNA synthesis after mixed lymphocyte culture (MLC) with allogeneic and autologous lymphocyte fractions. We performed these tests using, as responder cells, unfractionated mononuclear cells and T-cell-enriched populations obtained after nylon-wool column filtration. The results showed that nonadherent T-cell-enriched populations from both CLL patients and normal controls responded to allogeneic stimulation and that adherent cell fractions from normal individuals, and often from CLL patients, provided a stronger stimulus in MLC than did nonadherent cells. T-cell-enriched populations from normal individuals showed increased DNA synthesis after autologous mixed lymphocyte culture (AMLC) with adherent cells, but this phenomenon was uniformly lacking when the same experiment was performed with cell populations from CLL patients. This lack of response after AMLC was not due to serum factors or to short-range factors produced by inactivated CLL cells in culture. Possibly AMLC represents a recognition phenomenon between autologous T- and B-cells, and thus it may reflect the interaction of T-helper or suppressor cells and B-lymphocytes. The lack of autorecognition in CLL may reflect the monocional nature of the B-cells in this disease or a defect in helper or suppressor T-cells.