title: Anti-C1q antibodies in juvenile-onset systemic lupus erythematosus.
abstract: The objective of this study was to evaluate the presence of anti-C1q antibodies Hospital Israelita Albert Einstein Research Institute, São Paulo, Brazil in 67 juvenile systemic lupus erythematosus (JSLE) patients and 26 healthy controls and to assess the association of these antibodies with disease activity, nephritis, and presence of anti-double-stranded (ds)DNA. Anti-C1q antibodies were detected by ELISA. A higher frequency of anti-C1q antibodies was observed in JSLE patients compared to controls (20% vs. 0%, P = 0.016). Specificity of these antibodies was 100%[95% confidence interval (CI) 86.7-100%] and sensitivity was 19.4% (95% CI 10.7-30.8%) for a lupus diagnosis. The median anti-C1q antibodies was higher in JSLE patients compared to controls [median (range) 9.4 (5.5-127) vs. 7.3 (5-20) units, P = 0.004]. Remarkably, a positive Spearman's coefficient was found between anti-dsDNA and anti-C1q units (r = 0.42, P = 0.0004, 95% CI 0.19-0.60). Our results confirm a low frequency of anti-C1q antibody in our lupus populations, but the presence of anti-Clq antibodies appears to be a good marker for JSLE diagnosis.
authors.affiliation: Pediatric Rheumatology Unit, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil. adriana.jesus@icr.usp.br
authors.forename: A A
authors.initials: AA
authors.lastname: Jesus
authors.forename: C A
authors.initials: CA
authors.lastname: Silva
authors.forename: M
authors.initials: M
authors.lastname: Carneiro-Sampaio
authors.forename: M
authors.initials: M
authors.lastname: Sheinberg
authors.forename: C L
authors.initials: CL
authors.lastname: Mangueira
authors.forename: S K
authors.initials: SK
authors.lastname: Marie
authors.forename: B L
authors.initials: BL
authors.lastname: Liphaus
mesh_terms: D000293:Adolescent; D000974:Antibodies, Antinuclear / Q000097:blood; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002648:Child; D015922:Complement C1q / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D011237:Predictive Value of Tests
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D015415:Biomarkers; D015922:Complement C1q