The serum complement system in children on continuous ambulatory peritoneal dialysis

Abstract

Objective: During continuous ambulatory peritoneal dialysis (CAPD), the loss of complement factors via the dialysate may cause complement deficiencies. This hypothesis was tested in a group of children treated with CAPD. Design: Classical (CH50) and alternative (AP50) complement activity and serum levels of factors C1q, C3, C4, C3d, B, D, and P in CAPD patients were compared to normal controls and to children with preterminal renal failure. Setting: Patients were seen in a university hospital; normal controls were seen in an outpatient clinic of a general hospital. Patients: A group of 22 children on CAPD was compared to a normal control group of 44 children and to a group of 12 children with preterminal renal failure with a creatinine clearance below 25 mL/min/1.73 m2. Results: CH50, AP50, C3, and B were not significantly different from the control group in both the CAPD and preterminal groups. Factors C1q (p = 0.01) and C4, C3d, D, and P (p < 0.001) were higher in the CAPD group in comparison to the normal control group. The factors D (p < 0.001) and P (p = 0.02) were also elevated in the preterminal group. For the measured factors there was no significant difference between the CAPD group and the preterminal group. Conclusions: There is no deficiency of complement in children treated with CAPD. High levels of C3d and D can be explained by the reduction of their elimination by the kidney. The increased levels of the other factors are presumably due to increased synthesis in renal failure. This does not seem to be caused by CAPD.