T-cell growth factor-mediated proliferation of lymphocytes from a T-chronic lymphocytic leukaemia patient lacking mitogen and alloantigen responsiveness.

Peripheral blood lymphocytes from a patient with chronic lymphocytic leukaemia of T cell origin (T-CLL PBL), were found to lack PHA and Con A responsiveness and to have a very poor responder activity in mixed lymphocyte cultures. In spite of the presence of Ia-like antigens on 36% of the T-CLL PBL, negligible stimulator capacity in MLC was observed. Proliferation of the T-CLL PBL could be induced and maintained both by exogenous T cell growth factor (TCGF) containing PHA, and mitogen-free TCGF. In addition, restoration of the responder and stimulator capacity in MLC was obtained in the presence of mitogen-free TCGF. These results indicate that the lack of response to mitogens and alloantigens of the T-CLL PBL has to be attributed to the failure of these cells to produce TCGF upon activation.