title: Relationship of complement activation route with clinical manifestations in Japanese patients with systemic lupus erythematosus: a retrospective observational study.
abstract: OBJECTIVE
  To assess the relationship between the complement activation route and clinical manifestations in systemic lupus erythematosus (SLE).
  
  
  METHODS
  Patients with SLE in whom complement activation occurred were divided into two groups: those in whom the complement system was mainly activated through the classical pathway (low serum C3 and C4 levels; CP group); and those in whom the complement system was solely activated through the alternative pathway (low serum C3 with normal C4 levels; AP group). Clinical manifestations were compared between the groups.
  
  
  RESULTS
  The CP group had higher frequencies of arthritis, serositis, and nephritis, and a higher prevalence of anti-DNA antibodies compared to the AP group (arthritis: 50.0% vs. 13.0%, p = 0.0014; serositis: 37.5% vs. 13.0%, p = 0.0257; nephritis: 63.6% vs. 21.7%, p = 0.0003; anti-DNA antibodies: 73.9% vs. 30.4%, p = 0.0001). In contrast, the AP group had a higher frequency of anti-phospholipid (anti-PL) antibodies and a higher prevalence of antiphospholipid syndrome (APS) (anti-PL antibodies: 70.6% vs. 37.3%, p = 0.0136; APS: 39.1% vs. 5.7%, p < 0.0001).
  
  
  CONCLUSIONS
  Our results suggest that a different complement system mechanism may act in the pathogenesis of APS in patients with SLE.
authors.affiliation: Department of Gastroenterology and Rheumatology, School of Medicine, Fukushima Medical University , Fukushima , Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Sugimoto
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Asano
authors.forename: Shuzo
authors.initials: S
authors.lastname: Sato
authors.forename: Eiji
authors.initials: E
authors.lastname: Suzuki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Katakura
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Ohira
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017152:Antibodies, Antiphospholipid / Q000097:blood; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000175:diagnosis / Q000276:immunology; D003167:Complement Activation / Q000276:immunology*; D003176:Complement C3; D003181:Complement C4; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D017152:Antibodies, Antiphospholipid; D003176:Complement C3; D003181:Complement C4
keywords: Antiphospholipid syndrome; Complement; Systemic lupus erythematosus