Phagocytic cell function in response to immunosuppressive therapy

The increased incidence of pulmonary infection in human renal allograft recipients is presumably related to antirejection immunosuppressive therapy. To assess immunosuppressive-related disturbances of the immune responses of the lung, we evaluated the functional abilities of the pulmonary alveolar macrophage (PAM) and polymorphonuclear leukocyte (PMN) of rats in chemotaxis, phagocytosis, and superoxide-release assays following 30 days of intraperitoneal administration of cyclosporine, azathioprine, and/or prednisolone sodium succinate. None of these drugs affected superoxide release by stimulated PAMs or PMNs. Except for a transient inhibition by azathioprine, the drugs had no effect on phagocytosis of Staphylococcus aureus by either cell type. On the other hand, cyclosporine inhibited formyl-methionyl-leucyl-phenylalanine (FMLP)-directed chemotaxis by PAMs, and both FMLP and C5a stimulated chemotaxis by PMNs. Azathioprine had more dramatic effects on PAMs than on PMNs and prednisolone at 2 mg/kg inhibited PAMs. The results indicated that, with the exception of chemotaxis, the immunosuppressive agents largely spare nonspecific elements of host defense.