Cell-mediated and humoral immune responses or renal transplant recipients with cytomegalovirus infections.

Cell-mediated and humoral immune responses were determined in immunosuppressed renal transplant recipients. A micro-phytohaemagglutinin (PHA) stimulation test utilizing whole heparinized blood and a macro-PHA test utilizing separated, washed lymphocytes were used to study cell-mediated immunity. Humoral immune status was estimated by determining quantitative immunoglobulins and complement fixing (CF) antibody titres to cytomegalovirus (CMV) infection. Micro-PHA responses were found to be markedly depressed in patients undergoing immunosuppressive therapy and in patients with chronic uraemia. Macro-PHA responses were normal, indicating that serum factors were responsible for the depressed micro-PHA responses. Antibody responses to CMV infections were found to be ten to a hundred times higher than in normal persons. An inverse relationship was demonstrated between micro-PHA responses and peak CF antibody titres to CMV infections. Humoral immune responses appeared to compensate for depressed cell-mediated immunity as measured by the micro-PHA test. Four patients had very low micro-PHA responses, did not respond to their CMV infections with CF antibody, and died of mixed bacterial and viral infections. Serum immunoglobulins of two were studied and were shown to be greater than two standard deviations below the normal mean. These patients appeared more suppressed than other patients receiving similar therapy and thus probably retained higher concentrations of suppressive drugs.