title: Association between ongoing anti-C1q antibody production in peripheral blood and proliferative nephritis in patients with active systemic lupus erythematosus.
abstract: The aim of this study was to compare ongoing production of anti-C1q antibodies (anti-C1q) in peripheral blood with serum anti-C1q levels in patients with systemic lupus erythematosus (SLE), especially in patients with nephritis. Using the ELISPOT technique for the detection of IgG and IgA anti-C1q production, 21 patients with active SLE were investigated. ELISAs for IgG and IgA anti-C1q were compared with the ELISPOT results. Six of the patients were found to have proliferative nephritis (WHO grade III/IV) confirmed by renal biopsy. High numbers of IgG anti-C1q spot-forming cells (SFC), defined as > 20/10(5) plated peripheral blood mononuclear cells (PBMC), were exclusively observed in patients with proliferative nephritis (P < 0.0001). Serum levels of IgG anti-C1q were significantly increased in patients with proliferative nephritis (P = 0.039). High ongoing IgG anti-C1q production was observed in all patients with proliferative nephritis, which may be a contributory factor in the pathogenesis of this disorder. The detection of IgG anti-C1q production may be valuable in the clinical investigation of patients with suspected SLE nephritis.
authors.affiliation: Department of Rheumatology, Karolinska Hospital, Stockholm Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Gunnarsson
authors.forename: J
authors.initials: J
authors.lastname: Rönnelid
authors.forename: Y H
authors.initials: YH
authors.lastname: Huang
authors.forename: S
authors.initials: S
authors.lastname: Rogberg
authors.forename: B
authors.initials: B
authors.lastname: Nilsson
authors.forename: I
authors.initials: I
authors.lastname: Lundberg
authors.forename: L
authors.initials: L
authors.lastname: Klareskog
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D015922:Complement C1q / Q000276:immunology*; D004247:DNA / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000276:immunology*; D008181:Lupus Nephritis / Q000209:etiology / Q000276:immunology*; D008297:Male; D008875:Middle Aged
chemical_list: D001323:Autoantibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015922:Complement C1q; D004247:DNA