title: Correlation between serum anti-C1q antibody levels and renal pathological characteristics and prognostic significance of anti-C1q antibody in lupus nephritis.
abstract: OBJECTIVE
  To investigate the relationship between serum anti-C1q antibody levels and renal pathological characteristics in lupus nephritis as well as the prognostic significance of serum anti-C1q antibody.
  
  
  METHODS
  Seventy-three patients with biopsy-proven lupus nephritis were enrolled. Anti-C1q antibody was measured in serum samples taken within 7 days before renal biopsy and remeasured at the end of the first and the third month after treatment. All patients were followed at least once a month for 3 months. A cross-sectional study analyzed the relationship between serum anti-C1q antibody levels and renal histopathology and nephritic activity, while a longitudinal study evaluated the prognostic significance of anti-C1q antibody levels in lupus nephritis.
  
  
  RESULTS
  Fifty-eight of 73 patients (79.5%) were reported as having positive baseline serum anti-C1q antibody, with a mean level of 95.3 (+/- 55.2) U/ml. Significant differences were found in serum anti-C1q antibody levels between each World Health Organization (WHO) classification of lupus nephritis. The serum anti-C1q antibody level of WHO class IV was the highest. Serum anti-C1q antibody was positively correlated with the active and chronic indices in renal pathology. Patients with persistent high levels or increased titers of serum anti-C1q antibody tended to develop delayed remission in nephropathy. Serum anti-C1q antibody levels before and after treatment were relevant to renal remission, but serum anti-C1q antibody at the end of the third month after treatment was a stronger predictor for the prognosis after adjustment in the Cox's proportional hazards regression model.
  
  
  CONCLUSIONS
  Serum anti-C1q antibody is a valuable noninvasive biological marker for evaluation of renal involvement and lupus prognosis.
authors.affiliation: Department of Rheumatology and Clinical Immunology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Cai
authors.forename: Xiuyan
authors.initials: X
authors.lastname: Yang
authors.forename: Fan
authors.initials: F
authors.lastname: Lian
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Lin
authors.forename: Ming
authors.initials: M
authors.lastname: Liang
authors.forename: Jianwen
authors.initials: J
authors.lastname: Li
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Chen
authors.forename: Liuqing
authors.initials: L
authors.lastname: Liang
authors.forename: Shuguang
authors.initials: S
authors.lastname: Qin
authors.forename: Junzhou
authors.initials: J
authors.lastname: Fu
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D015922:Complement C1q / Q000276:immunology*; D003176:Complement C3 / Q000276:immunology; D003430:Cross-Sectional Studies; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007136:Immunoglobulins / Q000276:immunology; D007668:Kidney / Q000276:immunology / Q000473:pathology*; D008137:Longitudinal Studies; D008181:Lupus Nephritis / Q000097:blood / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D012720:Severity of Illness Index
chemical_list: D001323:Autoantibodies; D003176:Complement C3; D007136:Immunoglobulins; D015922:Complement C1q