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Serial peritoneal macrophage function studies in CAPD patients with peritonitis
1Department of Medical Research Veterans General Hospital, Taipei, Taiwan, Republic of China.
Abstract:
Continuous ambulatory peritoneal dialysis, peritoneal macrophage, IL-1, IFN-r, TNF, phagocytosis. Peritoneal macrophages (PM) perform first-line defense activity against peritonitis, the most important complication in CAPD therapy. Our longitudinal study compared the PM function in 14 patients in a low peritonitis occurrence group (LPOG) and 6 in a high peritonitis occurrence group (HPOG) before and during peritonitis; all started CAPD therapy after January 1988. The results show that at the onset of peritonitis, PM function including bactericidal killing (BA) activity, phagocytosis index (PI), H2O2 release, interleukin-1 (IL-1) and tumor necrosis factor (TNF) secretion can increase rapidly in the LPOG. However, this was absent in the HPOG. Both groups had a decrease of PM immunological function in the initial 7 to 10 days after onset of peritonitis, then PM functions began to return toward their pre-peritonitis state. However, in the HPOG, the recovery of PM function was very slow, resulting in significantly lower PM functions. In vitro, when normal PM were put into peritonitis dialysate, IL-1, TNF production and PI, BA activity of PM were decreased. This suppressor activity was absent in the peritonitis-free dialysate. These results suggest a suppressor factor(s) in the HPOG peritoneal dialysate may decrease the function of PM rather than cause easy peritonitis development.
Insights
Patients undergoing continuous ambulatory peritoneal dialysis (CAPD) with high peritonitis rates show impaired peritoneal macrophage (PM) function. Peritoneal dialysate in these patients may contain factors that suppress PM activity, increasing peritonitis risk.
Area of Science:
- Nephrology
- Immunology
- Infectious Diseases
Background:
- Peritoneal macrophages (PM) are crucial for defending against peritonitis, a major complication in continuous ambulatory peritoneal dialysis (CAPD).
- Understanding PM function differences between patients with low and high peritonitis occurrence rates is vital for improving CAPD therapy.
Purpose of the Study:
- To compare peritoneal macrophage function in patients with low versus high peritonitis occurrence rates during CAPD therapy.
- To investigate the impact of peritoneal dialysate on PM function in vitro.
Main Methods:
- A longitudinal study comparing PM function (bactericidal activity, phagocytosis index, H2O2 release, IL-1, TNF secretion) in 14 low peritonitis occurrence group (LPOG) patients and 6 high peritonitis occurrence group (HPOG) patients.
- Analysis of PM function before, during, and after peritonitis episodes.
- In vitro experiments exposing normal PM to peritonitis-free and peritonitis dialysates.
Main Results:
- At peritonitis onset, LPOG patients showed rapid increases in PM function (IL-1, TNF, phagocytosis, bactericidal activity), which was absent in HPOG patients.
- Both groups experienced a temporary decrease in PM function post-peritonitis, but HPOG patients showed significantly slower recovery.
- In vitro, peritonitis dialysate suppressed normal PM function (IL-1, TNF production, phagocytosis, bactericidal activity), an effect not seen with peritonitis-free dialysate.
Conclusions:
- Impaired peritoneal macrophage immune response is associated with higher peritonitis rates in CAPD patients.
- Peritoneal dialysate from HPOG patients may contain suppressor factors that impair PM function, contributing to increased peritonitis susceptibility.