[Factors contributing to the impairment of cellular immunity in cancer patients (author's transl)].

Factors contributing to the impairment of cell-mediated immunity in cancer patients were studied. Normal plasma enhanced the PHA-induced transformation of cancer lymphocytes. Cancer plasma suppressed the transformation of normal lymphocytes. The plasma factor(s), which might play an important role in the impairment of cell-mediated immunity in cancer, was further characterized to be heat-labile, being completely destroyed at 56 degrees C for 30 minutes. It was present on the surface of T lymphocytes, and was partially removable by digestion with 0.05% Bacto-trypsin. Moreover, the percentage of T cells in the peripheral blood of cancer patients was lower than that of normal as determined by the anti-human thymocyte serum cytotoxicity test and the spontaneous rosette forming test.