In vitro functional studies of mononuclear cells in patients with CLL. Evidence for functionally normal T lymphocytes and monocytes and abnormal B lymphocytes

In vitro functional studies of mononuclear cells from 34 patients with B‐cell type CLL were investigated and the results of these studies were as follows: 1 The T lymphocytes from patients with CLL were capable of responding normally to PHA or PWM, of inducing allogeneic normal B lymphocytes to respond to these mitogens and of stimulating normally to allogeneic lymphocytes in “one‐way” mixed lymphocyte reaction; 2 The monocytes from these patients were capable of enhancing the T lymphocyte response to mitogens and of stimulating normally to allogeneic lymphocytes; and 3 The leukemic B lymphocytes were incapable of responding to mitogens even in the presence of normal T lymphocytes and their enhancer cell activity on T lymphocyte response or their stimulating capacity on allogeneic lymphocytes was depressed. These observations suggest that the T lymphocytes and monocytes from patients with CLL are functionally normal while the leukemic B lymphocytes from these patients are functionally abnormal.