Significance of anti-C1q antibodies in the diagnosis of disease activity of systemic lupus erythematosus and lupus nephritis

Objective: To explore the significance of anti-C1q antibodies in diagnosis of systemic lupus erythematosus(SLE) with lupus flare and lupus nephritis(LN).Methods: By using ELISA,serum anti-C1q antibodies were detected from 102 SLE patients,60 patients suffered with other rheumatic disease,and 40 healthy cases.Then 102 SLE patients were divided into active group including 60 patients and stable groups including 42 patients,LN group including 50 patients and non LN groups including 52 patients on the basis of LN diagnostic criteria.The positive rate and level of anti-C1q antibodies were detected,then to analyze the correlation between the level of antiC1q antibodies and the results of laboratory detection for SLE patients.Results: The positive rate of anti-C1q antibodies in SLE patients was 64.7%,significantly higher than those in other control groups(P 0.05).The positive rate of anti-C1q antibodies in patients with active SLE was significantly higher than those in patients with inactive SLE(P0.01).Both the positive rate(P0.01) and serum levels of anti-C1q(P0.01) in group LN were significantly higher than those in group non LN.Serum level of anti-C1q antibodies showed a strongly positive correlation with SLEDAI score,anti-dsDNA antibodies,GLO,lgG,ESR,CRP and proteinuria and a negative correlation with WBC,C3,C4 and ALB.Conclusion:Anti-C1q antibodies are associated with SLE,LN and assessment of disease activity.It can not only reflect disease activity,but also act as a useful marker to diagnose patient condition and treatment efficacy.