Inhibition of normal lymphocyte transformation by plasma and lymphocyte factors in chronic lymphatic leukaemia.

Phytohaemagglutinin transformation of normal lymphocytes was significantly inhibited by the plasma and by extracts of lymphocytes in six out of eight cases of untreated chronic lymphatic leukaemia compared with similar material from matched control patients. Since the concentration of inhibitor in lymphocytes was much greater than that in plasma and both inhibitors were thermolabile, it is possible that the plasma inhibitor may be produced by the leukaemic cells. These findings indicate modifications of normal T-cell function by constituents of neoplastic lymphocytes but the effect may be due to exaggeration of a normal mechanism in which the surface properties of T cells are modified by products of B cells.