IgG and complement receptor expression in children treated by peritoneal dialysis

Area of Science:

• Immunology
• Nephrology
• Pediatrics

Background:

• Children undergoing peritoneal dialysis (PD) exhibit an elevated susceptibility to infections.
• White blood cells (WBCs) utilize IgG receptors (FcgammaRs) and complement receptors (CRs) for phagocytosis, a key immune defense mechanism.

Purpose of the Study:

• To investigate the expression levels of FcgammaRs and CRs on monocytes, macrophages, and neutrophils in both blood and peritoneal dialysis effluent (PDE) of children on PD.
• To assess how FcgammaR and CR expression changes in response to PD treatment and peritonitis episodes.

Main Methods:

• Blood and PDE samples from 39 PD children were analyzed using flow cytometry.
• Cells were labeled with monoclonal antibodies targeting specific FcgammaRs (CD16, CD32, CD64) and CRs (CD11b, CD35).
• Expression was quantified by measuring the percentage of positive cells and mean fluorescence intensity (MFI).

Main Results:

• Peritoneal cells displayed lower percentages of FcgammaR- and CR-positive cells but higher MFI (receptor number per cell) compared to blood cells, suggesting activation.
• FcgammaR and CR expression in blood and dialysate remained stable during the first year of PD.
• During peritonitis, blood monocyte receptor MFI increased (except CD32), while PDE macrophage and neutrophil percentages rose, though MFI changes were inconsistent.

Conclusions:

• Peritoneal cells in PD children show signs of activation with reduced receptor-positive cell counts but increased receptor density.
• Both blood and peritoneal cells can up-regulate receptor expression during peritonitis, but this response may not reach its maximum capacity.