肌联蛋白抗体在诊断胸腺瘤重症肌无力中的意义

目的探讨肌联蛋白抗体(Titin-ab)在诊断胸腺瘤重症肌无力(MGT)中的意义.方法采用ELJSA法检测73例不同病理类型MGT和58例不伴胸腺瘤重症肌无力(NTMG)患者血清中Titinab和乙酰胆碱受体抗体(AChR-ab)的水平.结果MGT组患者血清中Titin-ab阳性率为76.7%,明显高于NTMG组、其他疾病对照组和正常人组(P均<0.01);Titin-ab诊断MGT的敏感性低于胸腺CF/MR,但特异性高于后者(P<0.05);Titin-ab阳性率与不同胸腺瘤病理类型有关,其中上皮细胞型胸腺瘤组最高(95.1%);与胸腺瘤Masaoka病理分期无关(P>0.05);MGT患者Titin-ab与AChR-ab有明显相关性(r=0.496,P<0.01),而MGH患者则不明显(r=0.385,P>0.05).结论Titin-ab是一种诊断MGT(尤其是上皮细胞型胸腺瘤)较为敏感、特异、简便易行的实验室参数,它可能在MGT发病过程中起着重要的作用.

The signiificance of Titin antibody in diagnosing myasthenia gravis with thymoma

OBJECTIVE: To investigate the clinical significance of Titin antibody (Titin-ab) in diagnosing myasthenia gravis with thymoma (MGT). METHODS: Titin-ab and acetylcholine receptor antibody (AChR-ab) in the sera of 73 MGT patients with different thymic pathological patterns and 58 MG patients without thymoma (NTMG) were detected by ELISA. RESULTS: The positive rate of Titin-ab in MGT group was 76.7%, significantly higher than those of NTMG group, other neurologic diseases group and healthy control group (P < 0.01). The sensitivity of Titin-ab in diagnosis of MGT was significantly lower than that of CT scan or MR of thymus (P < 0.05), but the specificity of Titin-ab in diagnosis of MGT was significantly higher than that of CT scan or MR of thymus (P < 0.05). The positive rate of Titin-ab was mainly related to the thymic pathology and was the highest in the thymic epithelial thymoma (TET) subgroup (95.1%). There was no significant correlation between the positive rate of Titin-ab and the Masaoka's stage of thymoma (P > 0.05). The titer of Titin-ab was highly correlated to the titer of AChR-ab in MGT group (r = 0.496, P < 0.01), but not in MGH group (r = 0.385, P > 0.05). CONCLUSION: Detection of Titin-ab is a rather sensitive, specific, handy method in diagnosis of MGT (especially TET). It may play an important role in the pathogenesis of MGT.