Reticuloendothelial Fc receptor function in SLE patients. I. Primary HLA linked defect or acquired dysfunction secondary to disease activity?
Reticuloendothelial system (RES) Fc receptor-mediated immune clearance was measured in 18 patients with systemic lupus erythematosus (SLE). Only two patients, with major disease activity, had a prolonged T 1/2 of the blood disappearance curve of injected IgG coated red cells in comparison to 22 healthy controls. Circulating immune complexes (CIC) were studied with three methods: PEG precipitation, C1q-ELISA and the indirect granulocyte phagocytosis test (IGFT). The T 1/2 of the blood disappearance curve related significantly to the IGFT (r = 0.55, P less than 0.05) and not to the PEG and C1q-ELISA test. Although HLA-DR3 phenotype frequency was significantly increased in our SLE population (P less than 0.05), it was not related to Fc receptor function. Similarly, HLA-DR2 phenotype was not related to RES Fc receptor function. These data do not support the concept that a genetic HLA linked defect in reticuloendothelial Fc receptor function is a primary cause of SLE, predisposing the inflicted individual to immune complex deposition. However, Fc receptor-mediated immune clearance seems to be related to disease activity itself and to levels of CIC.
D000293:Adolescent; D000328:Adult; D000936:Antigen-Antibody Complex / Q000032:analysis; D003165:Complement System Proteins / Q000032:analysis; D005260:Female; D006680:HLA Antigens / Q000032:analysis*; D006207:Half-Life; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012157:Mononuclear Phagocyte System / Q000276:immunology*; D011961:Receptors, Fc / Q000276:immunology* / Q000378:metabolism
D000936:Antigen-Antibody Complex; D006680:HLA Antigens; D000949:Histocompatibility Antigens Class II; D007074:Immunoglobulin G; D011961:Receptors, Fc; D003165:Complement System Proteins