title: Anti-C1q antibodies in hepatitis C virus infection.
abstract: Autoantibodies against C1q have been described in many immune-complex diseases including hypocomplementaemic urticarial vasculitis and systemic lupus erythematosus (SLE). No study has focused on the role of anti-C1q antibodies in hepatitis C virus (HCV) infection. The aim of this study was (i) to evaluate the prevalence of anti-C1q antibodies in HCV infection; and (ii) to analyse the association of anti-C1q antibodies with clinical and biological features of HCV-mixed cryoglobulinaemia (MC) vasculitis. We searched for anti-C1q antibodies using an enzyme-linked immunosorbent assay (ELISA) test in 111 HCV patients (75 had cryoglobulin and 23 systemic vasculitis), 60 SLE patients and 109 blood donors. Anti-C1q antibodies were detected in 26% of HCV patients compared to 10% of healthy donors (P < 0.01), and 38% in patients with SLE. Although there was a higher prevalence of anti-C1q antibodies among HCV patients with type III cryoglobulin (50%, P < 0.01), the overall prevalence of anti-C1q antibodies was similar in HCV patients being cryoglobulin-positive or cryoglobulin-negative (26%versus 25%, P = 0.98). A significant association was found between anti-C1q antibodies and low C4 fraction of complement (P < 0.05). No association was found between anti-C1q antibodies and HCV genotype, severity of liver disease or with specific clinical signs of HCV-MC vasculitis. This study shows an increased prevalence of anti-C1q antibodies in HCV-infected patients. Anti-C1q antibodies were associated with low C4 levels. No association was found between anti-C1q antibodies and HCV-MC vasculitis, nor between anti-C1q antibodies and cryoglobulinaemia.
authors.affiliation: Service de Médecine Interne, Hôpital Pitié-Salpêtrière, 83 Boulevard de l'Hôpital, 75651 Cedex 13 Paris, France.
authors.forename: D
authors.initials: D
authors.lastname: Saadoun
authors.forename: S
authors.initials: S
authors.lastname: Sadallah
authors.forename: M
authors.initials: M
authors.lastname: Trendelenburg
authors.forename: N
authors.initials: N
authors.lastname: Limal
authors.forename: D
authors.initials: D
authors.lastname: Sene
authors.forename: J C
authors.initials: JC
authors.lastname: Piette
authors.forename: J A
authors.initials: JA
authors.lastname: Schifferli
authors.forename: P
authors.initials: P
authors.lastname: Cacoub
mesh_terms: D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D015922:Complement C1q / Q000032:analysis*; D003181:Complement C4 / Q000032:analysis; D003449:Cryoglobulinemia / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005814:Genes, Viral; D016174:Hepacivirus / Q000235:genetics; D018937:Hepatitis C Antibodies / Q000097:blood; D019698:Hepatitis C, Chronic / Q000276:immunology*; D006801:Humans; D008099:Liver / Q000821:virology; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D014657:Vasculitis / Q000276:immunology; D019562:Viral Load
chemical_list: D001323:Autoantibodies; D003181:Complement C4; D018937:Hepatitis C Antibodies; D015922:Complement C1q