In vivo studies on the mononuclear phagocyte system Fc receptor function in rheumatoid arthritis. Correlations with clinical and immunological variables.

The mononuclear phagocyte system Fc receptor function was assessed in 13 control subjects and 17 patients with rheumatoid arthritis (RA) by intravenous injection of IgG coated (IgG-RBC) or of heat-damaged (HD-RBC) 99mTc-labeled autologous erythrocytes. Although the clearance half-times of control and RA erythrocytes were not significantly different, the spleen to liver uptake ratios per surface area (S/Ls), determined by quantitative scintigraphic analysis, were significantly lower in RA patients than in controls. The S/Ls were significantly correlated with the Steinbrocker stages (r = 0.92; p less than 0.01), the disease duration (r = 0.73; p less than 0.01) and the total immunoglobulin levels (r = 0.73; p less than 0.01). The Clq binding activity of the sera was inversely correlated with the spleen (r = 0.90; p less than 0.01) and liver uptakes (r = 0.73; p less than 0.02). Our results therefore show an alteration of the Fc receptor function of splenic and hepatic mononuclear phagocytes in RA patients.