BACKGROUND AND OBJECTIVES The complement system plays an important role in the development of acute coronary syndrome (ACS). Complement C1q is an important initial component of the classical complement pathway and closely related to many chronic inflammatory diseases, including atherosclerosis (AS). We aimed to determine whether there was association between serum complement C1q and the severity of coronary stenosis. SUBJECTS AND METHODS 320 patients who underwent coronary arteriography (CAG) were stratified into non-ACS group (control group, n = 74), unstable angina group (UA group, n = 197) and acute myocardial infarction group (AMI group, n = 49) according to the severity of coronary stenosis and clinical manifestations. The severity of coronary stenosis was represented in Gensini score, and serum complement C1q level was compared using immunity transmission turbidity among three groups. RESULTS The level of complement C1q in AMI group was lower significantly than control group and UA group (P < 0.05), but there was no correlation between serum complement C1q and Gensini score (β=-0.086, P = 0.125). In nitrate-taking patients, serum complement C1q had a negative association with Gensini score (r=-0.275, P = 0.001), and in non-smokers, there was also a negative correlation (β=-0.159, P = 0.036). After calibrating smoking, drinking or statins, the serum complement C1q levels of control group, UA group and AMI group decreased in sequence (P <  0.05). Logistic regression analysis showed that the decreasing of serum complement C1q was an unfavorable factor for acute myocardial infarction (OR=0.984, 95 %CI=0.972∼0.997, P = 0.015) and for ACS (OR=0.984, 95 %CI=0.971∼0.984, P = 0.025) in drinking patients. Regrettably, ROC curve suggested that the accuracy in diagnosing coronary atherosclerotic heart disease by serum complement C1q was low (AUC=0.568, 95 %CI= 0.492-0.644, P = 0.076, sensitivity 73.6 %, specificity 58.1 %). CONCLUSION Serum complement C1q in ACS patients, in particular AMI patients, showed lower level. This finding suggests further decrease of complement C1q level in ACS patients may be a contributory factor to instability or rupture of atherosclerotic plaques. Combined with other clinical indicators, it can be helpful to predict the risk and severity of coronary stenosis.

中文翻译：

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血清补体C1q水平与急性冠状动脉综合征相关。

背景与目的补体系统在急性冠脉综合征（ACS）的发展中起着重要作用。补体C1q是经典补体途径的重要初始组成部分，与许多慢性炎性疾病（包括动脉粥样硬化（AS））密切相关。我们旨在确定血清补体C1q与冠状动脉狭窄程度之间是否存在关联。研究对象和方法将320例行冠状动脉造影（CAG）的患者分为非ACS组（对照组，n = 74），不稳定型心绞痛组（UA，n = 197）和急性心肌梗死组（AMI组，n = 49）根据冠状动脉狭窄的严重程度和临床表现。Gensini评分代表了冠状动脉狭窄的严重程度，并通过免疫传递浊度比较三组的血清补体C1q水平。结果AMI组补体C1q水平明显低于对照组和UA组（P <0.05），但血清补体C1q与Gensini评分无相关性（β= -0.086，P = 0.125）。在服用硝酸盐的患者中，血清补体C1q与Gensini评分呈负相关（r = -0.275，P = 0.001），在非吸烟者中，也呈负相关（β= -0.159，P = 0.036）。校正吸烟，饮酒或他汀类药物后，对照组，UA组和AMI组的血清补体C1q水平依次下降（P <0.05）。Logistic回归分析显示，血清补体C1q降低是急性心肌梗死的不利因素（OR = 0.984，95％CI = 0.972〜0.997，P = 0。015）和饮酒患者的ACS（OR = 0.984，95％CI = 0.971〜0.984，P = 0.025）。遗憾的是，ROC曲线提示血清补体C1q诊断冠状动脉粥样硬化性心脏病的准确性较低（AUC = 0.568，95％CI = 0.492-0.644，P = 0.076，敏感性为73.6％，特异性为58.1％）。结论ACS患者，尤其是AMI患者的血清补体C1q水平较低。这一发现表明，ACS患者补体C1q水平的进一步降低可能是动脉粥样硬化斑块不稳定或破裂的原因。结合其他临床指标，有助于预测冠状动脉狭窄的风险和严重程度。ROC曲线表明，血清补体C1q诊断冠状动脉粥样硬化性心脏病的准确性较低（AUC = 0.568，95％CI = 0.492-0.644，P = 0.076，敏感性73.6％，特异性58.1％）。结论ACS患者，特别是AMI患者的血清补体C1q水平较低。这一发现表明，ACS患者补体C1q水平的进一步降低可能是动脉粥样硬化斑块不稳定或破裂的原因。结合其他临床指标，有助于预测冠状动脉狭窄的风险和严重程度。ROC曲线表明，血清补体C1q诊断冠状动脉粥样硬化性心脏病的准确性较低（AUC = 0.568，95％CI = 0.492-0.644，P = 0.076，敏感性73.6％，特异性58.1％）。结论ACS患者，尤其是AMI患者的血清补体C1q水平较低。该发现表明ACS患者补体C1q水平的进一步降低可能是动脉粥样硬化斑块不稳定或破裂的一个促成因素。结合其他临床指标，有助于预测冠状动脉狭窄的风险和严重程度。这一发现表明，ACS患者补体C1q水平的进一步降低可能是动脉粥样硬化斑块不稳定或破裂的原因。结合其他临床指标，有助于预测冠状动脉狭窄的风险和严重程度。这一发现表明，ACS患者补体C1q水平的进一步降低可能是动脉粥样硬化斑块不稳定或破裂的原因。结合其他临床指标，有助于预测冠状动脉狭窄的风险和严重程度。