SUPPRESSION OF LYMPHOCYTE REACTIVITY BY BLOOD TRANSFUSIONS IN UREMIC PATIENTS III. REGULATION OF CELL-MEDIATED LYMPHOLYSIS

Abstract

Blood transfusions (BT) apparently can induce the generation of suppressor cells in the mixed lymphocyte reaction (MLR). Whether regulation of the alloimmune response could also be observed at the cell-mediated lympholysis (CML) level was investigated. The effect of the 1st 2 BT on cytotoxic T lymphocyte (CTL) differentiation in previously nontransfused uremic patients was analyzed. Different patterns of CML changes were noted. In 7 cases, marked CML reduction was observed after the 1st BT, and in 7 others CML remained unchanged or even increased after the 1st BT, but reduced CML occurred after the second. Increased CML was noted in the last 4 cases. When present, reduction in CML after BT could indeed occur upon in vitro restimulation by cells of the specific donor, but also by those of other individuals regardless whether they shared HLA antigens. Post-BT lymphocytes the CML of which was decreased could inhibit CML of autologous pre-BT cells when used as an irradiated 3rd-party at the initiation of the sensitization step. No correlation was generally observed between MLR and CML suppressions when both were tested in parallel assays. CML reduction could occur in the presence of unchanged or increased MLR; no cytotoxicity to the stimulating cells could be observed in direct cytolysis assays, so this inhibition can be attributed to suppressor cells of CTL differentiation that are generated in vivo after BT in man.