儿童期重症肌无力临床特点及免疫指标变化

Study on Clinical Features and Immunological Changes of Childhood-onset Myasthenia Gravis

目的:对儿童期重症肌无力(MG)患者的临床特点及免疫指标变化进行研究。方法:儿童期MG患者70例纳入病例组,健康儿童100例纳入对照组,收集病例组患儿的发病年龄、性别、MG分型、合并症及胸腺情况,归纳儿童期MG患者的临床特点;采集2组的外周血,检测病例组ACh R抗体阳性率,检测2组血清的免疫指标(Ig G、Ig A、Ig M,C3、C4),定量抗体芯片技术分析2组血清中Ig G亚型。结果:本组儿童期MG患者中,约半数在5岁以前发病,眼肌型占大多数(92.9%),20.0%患者合并甲状腺功能异常,14.3%的患者合并胸腺病变,ACh R抗体阳性率67.1%。与对照组比较,病例组外周血血清Ig G、Ig A、Ig M、C3及C4水平显著降低(P<0.05);在血清Ig G亚型中,Ig G1和Ig G3水平高于对照组(P<0.05),其余亚型差异无统计学意义(P>0.05)。结论:儿童期MG发病年龄在5岁之前及单纯眼肌型的比例占多数,自身抗体阳性率高,ACh R抗体以Ig G1和Ig G3为主,免疫球蛋白及补体水平明显减低。

Objective： To study the clinical features and immunological changes in patients of childhood-onset myasthenia gravis （CMG）. Methods： Seventy randomly selected CMG patients and 100 age-matched healthy controls were recruited. Clinical data of the CMG group such as onset age, MG classification, gender,comorbidities, and thymus abnormalities were collected to summarize the clinical features of CMG. Peripheral blood was collected from subjects in both groups. The CMG group serum AChRAb levels were detected.Immunological testing （IgG, IgA, IgM, C3, C4） was performed on both groups. The concentrations of IgG subclasses in both groups were quantified using Quantibody Human Ig Isotype Array. Results： Of the CGM patients in this study, approximately half had an onset age before 5 years old, and a majority presented with ocular type MG （92.9% ）. Comorbidities of thyroid abnormality were present in 20.0% of patients, and comorbidities of thymic abnormality were present in 14.3% of patients; 67.1% of patients were positive for AChRAb. Compared with the controls, the concentrations of serum IgG, IgA, IgM, C3, and C4 in CMG patients were significantly reduced （P〈0.05）. Among the IgG subclasses, IgG1 and IgG3 concentrations were higher in CMG patients than in healthy controls （P〈0.05）; the difference in other IgG subclasses was not significant （P〉0.05）. Conclusion： Our data show that a majority of CMG patients develop the disorder before 5 years of age, present with ocular type MG, and show a high positive rate of autoantibodies. Our results suggest that AChRAb is mainly composed of IgG1 and IgG3 and that CMG is characterized by decreased levels of immunoglobulins and complements.