Defective reticuloendothelial system Fc-receptor function in systemic lupus erythematosus.
To determine whether reticuloendothelial-system immunospecific Fc-receptor function is abnormal in patients with systemic lupus erythematosus, we studied the clearance of IgG-sensitized 51Cr-labeled erythrocytes by these splenic macrophage membrane receptors in 15 untreated patients. Fc-specific clearance rates were strikingly abnormal in 13 of 15 patients (half-times ranging from 80 to 2256 minutes, P less than 0.001 as compared to controls). Abnormal clearances correlated with immune-complex levels (as measured by the C1q-binding assay) and with disease activity. C1q-binding activity and anti-DNA titers also correlated with disease activity. The correlations of C3, C4, CH50 and factor B with abnormal clearance and disease activity were weaker or nonexistent. The significant correlations among clearance, disease activity and C1q-binding activity suggest that the defect in Fc-receptor function may lead to the prolonged circulation of immune complexes, thereby contributing to tissue deposition and damage.
D000328:Adult; D000936:Antigen-Antibody Complex / Q000032:analysis; D001323:Autoantibodies / Q000032:analysis; D001666:Binding Sites, Antibody; D003172:Complement C1 / Q000032:analysis; D003165:Complement System Proteins / Q000032:analysis; D004247:DNA / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology; D008180:Lupus Erythematosus, Systemic / Q000276:immunology* / Q000503:physiopathology; D008264:Macrophages / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012157:Mononuclear Phagocyte System / Q000276:immunology* / Q000503:physiopathology; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
D000936:Antigen-Antibody Complex; D001323:Autoantibodies; D003172:Complement C1; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D011947:Receptors, Antigen, B-Cell; D003165:Complement System Proteins; D004247:DNA