血清乙酰胆碱受体抗体阳性的全身型重症肌无力患者血浆补体活化产物水平及其临床意义

Plasma Levels and Clinical Significance of Complement Activation Products in Generalized Myasthenia Gravis Patients with Acetylcholine Receptor Antibodies

目的研究重症肌无力(MG)患者血浆补体活化产物C3a、C5a和s C5b-9的水平及免疫治疗前、后的变化,并分析其临床意义。方法收集40例乙酰胆碱受体(ACh R)抗体阳性的全身型MG患者(MG组)免疫治疗前、后及40例健康体检者(对照组)的血浆标本,采用ELISA方法检测C3a、C5a和s C5b-9的浓度,比较组间差异,并分析其与MG患者QMG评分、MMT评分及ACh R抗体水平的相关性。结果 MG组血浆C3a和s C5b-9的浓度均高于对照组(P<0.01);经免疫治疗后,MG组血浆C3a、C5a和s C5b-9浓度均降低;血浆C3a浓度与QMG评分(r=0.57,P<0.01)、MMT评分(r=0.38,P=0.03)均呈正相关;而C3a、C5a和s C5b-9浓度与ACh R抗体水平均无明显相关。结论 MG患者血浆补体活化产物水平高于正常人群,经免疫治疗后可显著降低,C3a水平增高与病情严重程度相关,可能成为判断病情的亚临床指标。

Aim To investigate the plasma levels of complement activation products（C3 a,C5 a and s C5 b-9） in patients with generalized myasthenia gravis（MG） before and after immunotherapy and analyze their clinical significance.Methods Plasma samples of 40 generalized MG patients with acetylcholine receptor（ACh R） antibodies were collected before immunotherapy and 4~6 months after the treatment from August 2015 to May 2017 in Huashan Hospital.Forty unrelated healthy blood donors were enrolled as healthy controls.Plasma concentrations of C3 a,C5 a and s C5 b-9 were measured by ELISA method.The differences between the two groups were compared.The relationships among plasma complement activation products levels and Quantitative Myasthenia Gravis（QMG） scores,Manual Muscle Test（MMT） scores and ACh R antibody titers were also analyzed.Results The concentrations of C3 a and s C5 b-9 in MG patients were significantly higher compared with the normal controls.There was no significant difference in C5 aconcentrations between the two groups.The concentrations of C3 a,C5 a and s C5 b-9 in MG patients were significantly decreased after immunotherapy（P〈0.01）.The plasma level of C3 a in MG patients before immunotherapy significantly correlated with the QMG scores（r=0.57,P〈0.01） and MMT scores（r=0.38,P=0.03）.No correlations were found between plasma concentrations of C3 a,C5 a,s C5 b-9 and ACh R antibody titers.Conclusion Plasma levels of complement activation products are elevated in MG patients and they are decreased after the immunotherapy.Plasma level of C3 a might be a potential useful biomarker in assessing disease severity of MG.