Increased Fc-receptor-mediated clearance via reticuloendothelial system in patients with nephrotic syndrome

Reticuloendothelial phagocytic cell function, which is an important participant in host defense, was investigated by studying the Fc-receptor-mediated clearance of IgG-anti-RhD-sensitized radiolabelled autologous erythrocytes in patients with nephrotic syndrome known to have an increased risk of infectious complications due to hypogammaglobulinemia. Patients with serum IgG concentrations less than 500 mg/dl had a significantly accelerated Fc-receptor-mediated clearance (t1/2 = 52 +/- 3.6 min) compared to patients with IgG levels greater than 500 mg/dl (t1/2 = 93 +/- 17 min) or healthy controls (t1/2 = 100 +/- 7.5 min). Serum IgG concentrations correlated significantly with Fc-receptor-mediated clearance (t1/2: r = 0.70; p = 0.035) in patients with nephrotic syndrome. These results indicate that Fc-receptor-mediated clearance by the reticuloendothelial system is enhanced in patients with nephrotic syndrome with low serum IgG concentrations and may, at least in part, compensate for reduced opsonic antibody concentration.