血清抗C1q抗体与狼疮肾炎活动性及病理改变的相关性

Correlation between serum anti-Clq antibodies and renal pathological characteristic in patients with lupus nephritis

目的探讨血清抗C1q抗体与狼疮肾炎（LN）肾组织病理改变的相关性，以及对LN的活动性的评价。方法用酶联免疫吸附法（ELISA）检测活动期LN患者60例和非LN患者60例血清中的抗C1q抗体，分析这一抗体与LN肾组织病理改变、活动指数及其他实验室参数的相关性。结果LN患者血清抗C1q抗体水平（89±26）U／ml较非LN患者（57±23）U／ml高（P〈0．01）；60例LN患者有同期。肾活检病理资料，按世界卫生组织（WHO）分型，Ⅱ型12例，Ⅲ型14例，Ⅳ型18例，V型16例。经方差分析显示，各病理类型间抗C1q抗体水平差异有统计学意义，其中以Ⅳ型LN的抗C1q抗体水平显著高于其他病理类型（P〈0．01）；C1q在肾组织的沉积与血清抗C1q抗体水平相关；血清抗C1q抗体水平与肾脏病变的活动指数（AI）及尿蛋白含量呈正相关（P〈0．01），与补体C3、C4水平呈负相关（P〈0．01）；抗双链DNA（dsDNA）抗体阳性的SLE患者，血清抗C1q抗体水平高于抗dsDNA抗体阴性者（P〈0．01）。结论血清抗C1q抗体水平在一定程度上反映LN肾脏的病理改变，并与肾脏病变活动指数有相关性，检测血清抗C1q抗体对评价LN病情及指导治疗有临床实用价值。

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 non- LN patients （57±23） U/ml （P〈0.01）. Twelve cases of renal biopsies were classified as WHOClass Ⅱ, fourteen cases ClassⅢ, eighteen cases ClassⅣ, and sixteen cases ClassV. Significant difference of serum anti-C1q Ab level between each class was found by ANOVA test, and serum anti-C1q Ab level of ClassⅣ was the highest （P〈C.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 conelated 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 anti- dsDNA was higher than that in the patients with negative anti-dsDNA （P〈0.01）. Conclusion Serum anti- C1q 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.