血清C1q检测在系统性红斑狼疮疾病活动性判断及狼疮肾炎诊断中的价值

目的  探讨系统性红斑狼疮（SLE）患者血清C1q水平变化对SLE疾病活动性判断及狼疮肾炎（LN）的诊断意义。方法  150例研究对象，根据临床资料，分为SLE组（60例）、其他风湿疾病组（30例）、其他肾脏疾病组（30例）及正常对照组（30例）4组，其中SLE组包括33例LN患者和27例非LN患者。采用免疫透射比浊法测定各组血清C1q水平，并与其他SLE活动性指标进行相关性分析。结果  ①SLE组的血清C1q水平低于其他风湿性疾病组、其他肾脏疾病组及正常对照组（F =41.428，P =0.000），其中LN组的血清C1q水平低于非LN组（t =-4.262，P =0.000），SLE病情活动期患者C1q水平低于病情稳定期患者（t =-5.159，P =0.000）。②在SLE组中C1q诊断LN的敏感性为66.7%，特异性为59.3%。工作特征曲线的曲线下面积为0.717。③相关分析表明，SLE患者血清C1q水平与C3、C4呈正相关，与SLE疾病活动指数积分呈负相关（r=0.593、0.448和-0.589，P =0.000）。结论  血清C1q不仅有助于SLE及LN的诊断，且对SLE的病情评估及疗效判断具有重要参考价值。

Significance of detecting serum C1q level in diagnosis of systemic lupus erythematosus with lupus flare and lupus nephritis

Objective To explore the serum level of complement 1q (C1q) in systemic lupus erythematosus patients and to analyze its significance in diagnosis and prognosis of systemic lupus erythematosus with lupus flare and lupus nephritis (LN). Methods According to the clinical data, 150 cases of subjects were divided into four groups. There were 60 cases in SLE group, 30 cases in other rheumatic disease group, 30 cases in other kidney disease group and 30 cases in normal control group. The SLE group contained 33 cases of LN patients and 27 cases of non-LN patients. The serum level of C1q was measured by immune transmission turbidimetry. The correlations between the serum level of C1q and other disease activity parameters such as SLEDAI scores, C3 and C4 levels were analyzed. Results The serum level of C1q in the SLE group was significantly lower than that of the other rheumatic disease group, the other kidney disease group and the normal control group (F = 41.428, P = 0.000). The LN patients showed a significantly lower level of serum C1q than the non-LN patients (t = -4.262, P = 0.000). The SLE patients in active stage showed a significantly lower level of serum C1q than the stable patients (t = -5.159, P = 0.000). The sensitivity and specificity of C1q to diagnose LN in the SLE group were 66.7% and 59.3% respectively. The area under ROC curve was 0.717. Correlation analysis showed that the serum level of C1q was positively correlated with C3 and C4 concentrations but negatively correlated with the SLEDAI scores (r = 0.593, 0.448 and -0.589 respectively, and P = 0.000). Conclusions C1q may not only contribute to the diagnosis of SLE and LN, but also reflect the disease activity and treatment effect.