Effects on cancer patients of leukapheresis with the continuous-flow blood cell separator. II. Immunologic parameters in vitro.

The immunologic effects of leukapheresis on cancer patients and three other groups of donors using the continuous-flow blood cell separator are presented according to the protocol described in the preceding article. Transient declines were noted in per cent T-lymphocytes of some, but not all, leukapheresed normal donors and cancer patients. These declines were comparable to the small declines observed in sham donors and the fluctuations in per cent T-lymphocytes noted in individuals who did not undergo leukapheresis. There were no changes in lymphocyte-mediated cytotoxicity to a melanoma cell line in 2 of 4 melanoma patients, while values in 2 patients fell by about one-half within 4 hours and returned to preleukapheresis levels by 24 hours. Release of macrophage migration inhibition factor by lymphocytes from all 4 cancer patients and 4 normal donors, in whom this parameter was studied, fell transiently and returned to preleukaphresis levels within 24 hours. Blastogenic responses of lymphocytes from cancer patients and normal donors to phytohemagglutinin (PHA) and in one way mixed lymphocyte reactions increased in several individuals and decreased slightly in others. There appears to be no significant immunosuppressive effects (within the parameters studied) of a single leukapheresis for lymphocytes on the blood cell separator, since changes in lymphocyte parameters were relatively minor, transient, and variable and, where studied, paralleled fluctuations observed in sham donors and individuals not undergoing leukapheresis.