Phagocytic capacity of human leukocytes preincubated with Imuran and prednisone.

The phagocytic and microbicidal activities of human polymorphonuclear leukocytes (PMNL) were tested after a short-term preincubation of phagocytic cells with Imuran or Prednisone, using C. albicans strains as a test organism. The tests showed that both immunosuppressive agents reduced significantly the microbicidal activity of PMNL cells by 35-40%. Detectable differences in the phagocytic activity and phagocytic index values were not statistically significant. The decreased ability of PMNLs to kill ingested C. albicans strains appears thus to sensitively reflect the altered PMNL function and can be utilized in the biologic monitoring of immunosuppression. The reduced microbicidal potential of phagocytic cells may be also one of the causes of recurrent microbial infections that are so frequent in immunosuppressant-treated patients.