title: Anti-C1q antibodies and systemic lupus erythematosus in the Tunisian population.
abstract: OBJECTIVE
  The presence of a wide variety of autoantibodies is a characteristic feature of systemic lupus erythematosus (SLE). Although non-specific, anti-complement C1q (anti-C1q) were shown to correlate with the occurrence of active nephritis. The present study aimed to investigate the prevalence of anti-C1q in Tunisian SLE patients and their association with clinical manifestations, especially renal involvement.
  
  
  METHODS
  IgG anti-C1q antibodies were assessed by Elisa in 98 SLE patients, 55 patients with rheumatoid arthritis (RA) and 65 healthy individuals (HI).
  
  
  RESULTS
  Anti-C1q were found in 53 (54.1%) patients with SLE, three (5%) patients with RA and six (9.3%) HI. Among the 65 patients with renal involvement, anti-C1q were present in 35 (53.8%) patients. There was no significant association between anti-C1q and renal or extrarenal manifestations. In addition, there was no correlation between anti-C1q titer and SLEDAI index. Anti-C1q were significantly associated with anti-nucleosome (P=0.001), anti-Sm (P=0.01) and a low C4 level (P=0.046). Concomitant presence of anti-C1q and anti-dsDNA antibodies was not associated with renal manifestations.
  
  
  CONCLUSIONS
  Our study shows that prevalence of anti-C1q was comparable with that previously reported in Caucasian populations. These antibodies were associated with a low C4 level. However, there was no association between anti-C1q and renal involvement or severity of nephritis.
authors: Laboratory of Microbiology-Immunology, Farhat Hached Hospital, Ibn Al Jazzar street, 4000 Sousse, Tunisia.
authors: B
authors: B
authors: Trad
authors: H
authors: H
authors: Ben Hassine
authors: M
authors: M
authors: Khalifa
authors: N
authors: N
authors: Idriss
authors: F
authors: F
authors: Slama
authors: F
authors: F
authors: Bahri
authors: C
authors: C
authors: Laouani Kechrid
authors: J
authors: J
authors: Boukadida
authors: R
authors: R
authors: Sghiri
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000032:analysis / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D015922:Complement C1q / Q000276:immunology*; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011153:Population; D012189:Retrospective Studies; D016036:Seroepidemiologic Studies; D014416:Tunisia / Q000453:epidemiology; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D015922:Complement C1q