Periodic elevation of complement activation products in peritoneal dialysis effluent

Area of Science:

• Nephrology
• Immunology
• Biochemistry

Background:

• Chronic ambulatory peritoneal dialysis (CAPD) patients often display impaired peripheral white blood cell (WBC) function, including reduced chemotactic receptor expression and desensitization.
• Chronic complement activation, potentially due to uremia, the peritoneal catheter, or dialysis fluid, is hypothesized to cause these WBC alterations.

Purpose of the Study:

• To assess complement activation products, specifically C3bi, in peritoneal dialysis effluent.
• To quantify peritoneal polymorphonuclear leukocyte (PMN) and monocyte receptor expression (CR3 and C5a) in CAPD patients.
• To investigate the relationship between complement activation products, WBC receptor expression, and peritonitis incidence.

Main Methods:

• Longitudinal measurement of C3bi levels in peritoneal dialysis effluent from eight CAPD patients over 6-8 months.
• Quantification of peritoneal PMN and monocyte CR3 and C5a receptor expression using flow cytometry.
• Correlation analysis between dialysate C3bi levels, receptor expression, and peritonitis incidence.

Main Results:

• Six out of eight patients maintained stable C3bi levels (<5 µg/ml).
• Two patients showed periodic C3bi elevations unrelated to peritonitis.
• No correlation was found between dialysate C3bi levels and peritoneal PMN/monocyte CR3 or C5a receptor expression.
• Peritonitis incidence varied significantly between the two patients with elevated C3bi, suggesting no direct relationship.

Conclusions:

• The origin of activated complement components in the peritoneal cavity requires further investigation.
• Dialysate C3bi levels do not appear to correlate with altered peritoneal immune cell receptor expression in CAPD patients.
• Elevated C3bi levels in peritoneal dialysis effluent may not be directly linked to an increased risk of peritonitis.