Interferon-gamma (IFN-gamma) as in vitro enhancing factor of peritoneal macrophage defective bactericidal activity during continuous ambulatory peritoneal dialysis (CAPD).

Interferon-gamma (IFN-gamma) can be considered a primary factor required in vitro and in vivo for inducing endocellular lysis of microorganisms by peritoneal macrophages (PM luminal diameter), an essential activity in continuous ambulatory peritoneal dialysis (CAPD) patients that prevents bacterial peritonitis. In 22 uremic patients treated with CAPD we analyzed: (1) the amount of IFN-gamma released by elicited peritoneal lymphocytes (PL); (2) oxidative metabolism and microbicidal activity by elicited PM luminal diameter; (3) immunoglobulin G (IgG) Fc-receptor expression on PM luminal diameter membrane; (4) the effect on PM luminal diameter hydrogen peroxide (H2O2) generation, bactericidal activity, and IgG Fc-receptor expression exerted in vitro by human recombinant IFN-gamma (rIFN-gamma). Results demonstrate that IFN-gamma release by elicited PL is lower in some CAPD patients with high peritonitis incidence (HPI) than in healthy donors or in CAPD patients with low peritonitis incidence (LPI). Simultaneously, PM luminal diameter from CAPD patients with HPI are characterized by a decreased ability to generate oxygen metabolites, to kill bacteria, and by a lack in IgG Fc-receptor expression; these defects were completely cured after being treated with rIFN-gamma. These results show that the IFN-gamma treatment in vitro could strengthen PM luminal diameter phagocytosis, oxygen metabolite generation, and bacterial killing in CAPD patients with HPI, and suggest that IFN-gamma may be considered a possible therapy in vivo for these patients.