Correlation between serum anti-C1q antibodies and renal pathological characteristic in patients with lupus nephritis / 中华风湿病学杂志

ABSTRACT

Objective To analyze the correlation between serum anti-C1q antibody (anti-C1q Ab)and renal pathological characteristic,disease activity as well as some laboratory tests in patients with lupus nephritis (LN).Methods Serum anti-C1q antibodies were detected by enzyme-linked immunosorbant assay ELISA) in 120 patients with systemic lupus nephritis (SLE),which included 60 LN patients and 60 non-LN patients.Renal biopsy was conduted in all LN patients.The relationships between serum anti-C1q Ab level and renal pathohistology,lupus nephritis activity,as well as some laboratory parameters were analyzed.Results The mean level of serum anti-C1q Ab in LN patients was (89+26) U/ml,significantly higher than that of nonLN patients (57±23) U/ml (P＜0.01).Twelve cases of renal biopsies were classified as WHO Class Ⅱ,fourteen cases Class Ⅲ,eighteen cases Class Ⅳ,and sixteen cases Class Ⅴ.Significant difference of serum anti-C1q Ab level between each class was found by ANOVA test,and serum anti-C1q Ab level of Class Ⅳ was the highest (P＜0.01).Renal biopsies showed a positive correlation between serum anti-C1q Ab level and activity index of renal pathohistology (P＜0.01).Renal deposition of C1q was related with the level of serum anti-C1q Ab.Serum anti-C1q Ab level was positively correlated with proteinuria (P＜0.01),and negatively correlated with levels of C3 and C4 (P＜0.01).Mean level of serum anti-C1q antibody in SLE patients with positive antidsDNA was higher than that in the patients with negative anti-dsDNA (P＜0.01).Conclusion Serum antiC1q Ab level is significantly associated with lupus nephritis activity and renal pathohistology.It is a useful marker to predict renal lesion and disease activity in lupus nephritis.