OK432-induced killer cell activity: potential method for monitoring immunological complications after renal transplantation.

BACKGROUND: Various clinical and biochemical parameters are currently in use for monitoring allograft rejection. However, the mechanism of allograft rejection is complex and it is frequently difficult to obtain a prompt and accurate diagnosis. We examined the usefulness of OK432-induced killer cell activity as an immunological monitoring system for acute renal rejection after renal transplantation. METHODS: Twenty-four renal transplant recipients, seven patients on haemodialysis, and 10 normal volunteers were enrolled in our study. The killer cell activity of peripheral blood mononuclear cells was induced by culturing these cells with the immunopotentiator, OK432, a heat and penicillin-treated lyophilized powder of the Su-strain of Streptococcus pyogenes. RESULTS: The OK432-induced killer cell activity of renal transplant recipients without acute rejection (stable recipients) was significantly lower than in normal volunteers. In four renal transplant recipients with acute rejection, the killer cell activity was significantly higher than in stable recipients. In three recipients suffering from opportunistic infections, killer cell activity was significantly suppressed compared with stable recipients. CONCLUSIONS: Our new test utilizing OK432-induced killer cell activity is potentially useful for monitoring the immunological state and complications after renal transplantation.