Suppressor cells in end-stage renal disease. Functional assays and monoclonal antibody analysis

Suppressor cell activity after concanavalin A induction was studied in peripheral blood mononuclear cells of patients undergoing long-term hemodialysis. Suppression both of the mixed lymphocyte reaction and of allogeneic cells stimulated with phytohemagglutinin was significantly higher with peripheral blood mononuclear cells from patients undergoing hemodialysis than with cells from control subjects. Expression of the Ia antigen on T lymphocytes (associated with immunologic activation) was studied by staining with monoclonal antibodies and two-color fluorescence analysis in a computer-linked cytofluorograph. In unstimulated cells, there was no significant difference between the patients and control subjects. After concanavalin A induction, the percentage of T4, and particularly of T8, cells expressing the Ia antigen was significantly higher in the group undergoing hemodialysis. The functional suppression seen after concanavalin A induction in the mixed lymphocyte reaction was significantly reduced by treatment with OKT8 monoclonal antibody and complement; in phytohemagglutinin cultures, both OKT8 and OKIa*1 antibodies were effective. The reduced in vitro response of uremic lymphocytes may thus be a consequence of increased suppressor activity associated with the T8-positive, Ia-positive subset of T cells.