title: Detection of circulating immune complexes with a Raji cell enzyme immunoassay.
abstract: The Raji cell assay for circulating immune complexes (CIC) is frequently the method of choice when the detection of large, complement fixing complexes is desired. We have developed an enzyme-linked immunosorbent assay modification (Raji-ELISA) of the Raji cell technique which is easy to perform, uses commercially available reagents and is more convenient than the conventional Raji cell radioimmune assay (Raji-RIA). Fourteen samples were tested by both assays and a good correlation was observed (P = 0.05). Sera from patients with suspected immune complex associated diseases were tested in the Raji-ELISA. Unsensitized Raji cells gave a value of 1.25 micrograms of immune complex associated IgG/ml. Using 2 standard deviations as a cutoff to determine positivity, 2 of 32 healthy controls (6.2%) had elevated levels of circulating immune complexes. In our study population, 9 of 23 cancer patients (39.1%), 10 of 13 patients with autoimmune diseases (76.9%), 3 of 17 patients with positive rheumatoid factor titers (17.6%), 1 of 23 pregnant patients (4.3%), 1 of 5 preeclamptic patients (20%) and 9 of 30 other patients with suspected immune complex associated diseases (30%) had elevated levels of CIC.
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex / Q000032:analysis*; D001327:Autoimmune Diseases / Q000276:immunology; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D011225:Pre-Eclampsia / Q000276:immunology; D011247:Pregnancy; D011817:Rabbits; D012217:Rheumatoid Factor / Q000032:analysis
chemical_list: D000936:Antigen-Antibody Complex; D012217:Rheumatoid Factor