Autoimmunity in ocular and generalised myasthenia gravis

Restricted ocular myasthenia gravis (OMG) and generalised myasthenia gravis (GMG) have been shown to differ in a number of respects. In OMG, anti-acetylcholine receptor, antistriational and antinuclear antibodies were rare relative to their frequency in GMG. In contrast, antithyroid antibodies and a history of thyroid disease were much more prevalent in OMG than in GMG. OMG was not associated with the female predominance seen in GMG and appeared to be relatively common in some races rather than others. It is suggested that different pathogenetic mechnisms are responsible for these two forms of MG.     

重症肌无力患者胸腺切除术后合并视神经脊髓炎1例（附文献复习）

目的：分析重症肌无力（MG）患者胸腺切除后合并视神经脊髓炎的临床特点,探讨两者合并发生的机制。方法：结合文献对1例MG胸腺切除后合并视神经脊髓炎患者的临床特点和血清学改变进行分析。结果：现有的MG合并视神经脊髓炎的文献报道中,绝大多数（13/15例）在胸腺切除后发生。胸腺切除后抑制T细胞产生减少,B细胞过度增殖,自身免疫抗体增加,可能与视神经脊髓炎的发病有关。此外,HLAB8、DR2和DR3也可能与MG合并视神经脊髓炎的发生相关。结论：MG患者胸腺切除后引起的免疫系统改变（如血清中抑制T细胞数的改变和自身抗体的出现）,患者的HLA抗原类型（如HLA-B8、DR2和DR3）可能与合并视神经脊髓炎的发生相关。     

Immunogenetic heterogeneity and associated autoimmune disorders in myasthenia gravis: a population-based survey in the province of Ferrara, northern Italy

Introduction - The well-established relationship between myasthenia gravis (MG) and HLA antigens varies among different ethnic groups. In Caucasians B8 and/or DR3 alleles have been found associated with young MG women without thymoma and with high titres of acetylcholine-receptor antibody (AChR Ab). An increased frequency of haplotype HLA-A3, B7 and/or DR2 has been observed in older MG patients with low AChR Ab levels. So far, there is no convincing evidence for an association between a specific haplotype HLA and ocular MG or MG with thymoma. MG subjects often show other concurrent autoimmune disorders suggesting a more general inherited predisposition to autoimmunity. We performed a community-based study to verify the HLA-A, B, C, DR and DQ profile on ethnically homogeneous MG patients and with the aim to estimate the frequency of concurrent autoimmune diseases and to compare HLA phenotypes to autoimmune status in different MG patients groups. Methods - Forty-seven patients, living in the province of Ferrara, were followed-up in our neurologic department and typed for HLA Antigens. In addition a set of immunological laboratory tests was performed. Results - We found a trend towards an increased B8 and DR3 frequencies in total affected population; an association between B8 allele and early onset of generalized MG sustained by thymic hyperplasia. The DR3 allele is statistically associated with the presence of additional autoimmune disorders. Conclusions - Our data support the hypothesis of a genetically-based heterogeneity of the disease and show an increased prevalence of associate autoimmune conditions in MG patients.     

Strong association of MuSK antibody-positive myasthenia gravis and HLA-DR14-DQ5

The authors studied the HLA profile of 23 white Dutch patients with muscle-specific kinase antibody-positive myasthenia gravis (MuSK Ab+ MG) and found an association with HLA-DR14-DQ5 (odds ratio 8.5; 95% CI 3.9 to 18.7; p = 4.9 x 10(-5)). Fifty-two percent of the patients carried the DR14 allele compared with 5% of the controls (p = 1.0 x 10(-8)). This association between MuSK Ab+ MG and a relatively rare HLA haplotype differs from the previously described association of early-onset acetylcholine receptor Ab+ MG with HLA-B8-DR3.     

Autoantibody formation after bone marrow transplantation. Comparison between acetylcholine receptor antibodies and other autoantibodies and analysis of HLA and Gm markers

Clinical myasthenia gravis has been reported in an increased frequency after bone marrow grafting. The number of bone marrow transplanted patients making IgG autoantibodies directed against the autoantigens cardiolipin, SS-B (La) and thyroglobulin was found to be significantly lower as compared to the autoantigen acetylcholine receptor protein. The occurrence of antibodies to single-stranded DNA was found in a lower frequency than acetylcholine receptor antibodies but the difference was not statistically significant. Antibodies to cardiolipin were frequently observed prior to grafting. The G1m1,2 and G3m5 phenotype frequency did not differ in individuals who developed receptor antibodies from that found in the normal population. Analysis of HLA antigens in this patient group revealed no association to HLA B8/DR3 or B35/DR1. This may indicate that the etiology of myasthenia gravis induced by bone marrow grafting differs as compared with the spontaneous form of myasthenia gravis and the penicillamine-induced disease.     

Identification of genomic typing of non-DR3 HLA class II genes associated with myasthenia gravis

HLA association with myasthenia gravis (MG) has been studied in a series of 114 patients using class I and class II genotyping after PCR amplification. Positive association was found with DR3, particularly in women (RR=2.6) and in early MG onset (RR=3.4). DRB1, DRB3, DQB1, DQA1 and B (B8 and B18_genotyping revealed that the association was predominantly with the B8 DRB1^*03 DRB3^*0101 DQB1^*0201 DQA1^*0501 ancestral haplotype. This haplotype frequency was also increased in patients with thymic hyperplasia (RR=3.5) and was greatly reduced in patients with thymona (RR=0.35). Sixteen out of 48 patients carrying this 8.1 ancestral haplotype showed absence of B8 (n=4) or of DR3 (n=12). HLA class II genotyping further revealed the existence of two other significant associations. MG was positively associated with the DQB1^*0604 allele (RR=3.4), particularly in patients with thymona (RR=5.7). Furthermore, the disease was negatively associated with DR1 in females (RR=0.32). These data suggest that MG is placed under the control of at least three distinct genes: (1) a class II predisposing gene in the 8.1 ancestral haplotype; (2) a thymona-associated class II allele on the DQB1^*0604 haplotype; and (3) a protective allele DR1.     

非胸腺瘤性眼外肌麻痹起病重症肌无力胸腺切除时机探讨

目的比较非胸腺瘤性眼外肌麻痹起病重症肌无力(ocular onset myasthenia gravis,OMG-O)患者于不同病程行胸腺切除后病情缓解与向全身型重症肌无力(GMG)转化的差异,以期对手术时机进行探讨。方法采用双向队列研究方法,对作者医院2005年1月至2017年9月因药物治疗效果不佳而行胸腺切除的86例OMG-O患者,按起病至手术时间间隔分为早手术组(≤1年)、晚手术组(>1年),比较两组患者不同随访时间理想状态(干预后状态达到轻微异常及更好)率、GMG转化率的差异。结果 (1)与早手术组比较,晚手术组少年MG(<18岁)比例较高,起病至手术时间间隔、起病至使用激素时间间隔、激素用药时间较长(均P <0.05)。(2)与晚手术组比较,早手术组术后第3年理想状态率高(P=0.029),而第2、4~8年理想状态率有升高趋势,但差异无统计学意义(P>0.05)。(3)9例术后发生GMG转化,起病至发生GMG转化时间中位数17.8个月,其中6例(66.7%)在3年内发生GMG转化。早手术组与晚手术组间GMG转化率比较,差异无统计学意义(12.5%比8.7%;χ~2=0.049,P=0.825)。结论对于药物治疗无效或不耐受的OMG-O患者,早期行胸腺切除手术疗效较好;但即使手术,仍有可能发生GMG转化,约1/2患者于起病后1.5年内发生,约2/3于起病后3年内发生。     

Ocular myasthenia gravis: predictive value of single-fiber electromyography.

Extraocular muscle weakness is the most common presenting sign of myasthenia gravis (MG). More than half of patients presenting with symptoms isolated to these muscles (OMG) develop generalized myasthenia gravis (GMG) over the course of their illness. No clinical, laboratory, or electrophysiological features are recognized that identify these high-risk patients. We have therefore assessed the ability of single-fiber electromyography (SFEMG) to predict the development of GMG in patients presenting with OMG. Thirty-nine consecutive patients presenting with OMG underwent SFEMG of the extensor digitorum communis muscle as well as a battery of other laboratory and imaging studies at the time of diagnosis. All patients were followed prospectively for a minimum of 24 months or until they developed GMG. Two patients were excluded, leaving 37 for assessment. Twenty remained with pure OMG for the entire follow-up period (mean, 55 months). Twenty-six of the 37 had abnormal SFEMG studies at presentation. Eleven of these remained with OMG and 15 developed GMG. Fifty-eight percent of patients with an abnormal SFEMG developed GMG, whereas 82% of those with a normal study remained with OMG. Thus, a normal SFEMG was associated with MG remaining restricted to the extraocular muscles. (P = 0.036, Fisher's exact test), but an abnormal SFEMG was not predictive of subsequent development of GMG.     

Heterogeneous immunogenetic background in Japanese adults with myasthenia gravis

The aim of this study was to elucidate the roles of human leukocyte antigen (HLA) class II genes in disease susceptibility in Japanese adult patients with myasthenia gravis (MG). A number of studies have shown that MG is correlated with DR3 in Caucasians. In Japanese, infantile MG is associated with DR9, but the HLA class II alleles associated with adult MG remains unclear. HLA-DRB1 and DQB1 alleles were determined by genotyping in 75 Japanese adult patients with MG and in 115 race-matched healthy adults. No statistically significant difference was observed in the overall prevalences of DRB1 and DQB1 alleles between MG patients and healthy controls, even when the patients and controls were stratified on the basis of their gender. MG patients with DQB1*0604 were younger and those with DQB1*0402 were older at disease onset than those without (P=0.03 and 0.008, respectively). Concomitant autoimmune thyroid disease was associated with DRB1*0803 (P=0.0009, corrected P=0.04). In addition, anti-acetylcholine receptor antibody levels were significantly higher in patients with DQB1*0604 than in those without (P=0.045). These findings indicate that immunogenetic backgrounds in Japanese adult MG patients are heterogeneous and are apparently different from those in Caucasian patients.     

重症肌无力患者汉密尔顿抑郁量表评分分析

目的探讨重症肌无力(myasthenia gravis,MG)患者汉密尔顿抑郁量表(Hamilton depression rating scale,HDRS)评分情况及其影响因素分析。方法横断面研究2013-07—2015-03作者医院就诊的188例MG患者的临床资料和HDRS评分情况,并根据HDRS评分将其分为抑郁组和非抑郁组,分析两组MG患者的临床特点及其与HDRS评分间的关系。结果所纳入MG患者男女比例为1.02∶1,眼肌型重症肌无力(ocular myasthenia gravis,OMG)和全身型重症肌无力(generalized myasthenia gravis,GMG)的比例为1.2∶1,以OMG起病和以GMG起病患者的比例为6.2∶1,病程中位数为2年,四分位数间距为1.8年,平均量化重症肌无力评分(quantitative myasthenia gravis,QMG)为(6.7±2.3)分,平均HDRS评分为(8.7±3.4)分,并发抑郁者65例,未并发抑郁者123例。影响HDRS评分和抑郁发生的相关因素包括性别(P0.01)、MG类型(P0.01)、QMG得分(P0.01)和美国重症肌无力协会(myasthenia gravis foundation of America,MGFA)分型(P0.01)、有无甲状腺功能亢进(P0.05)。结论影响MG患者HDRS评分和抑郁发生的相关因素包括性别、MG类型、QMG评分和MGFA分型、有无甲状腺功能亢进,充分认识其抑郁发生情况有利于更好地治疗MG。     

Correlation of C3 level with severity of generalized myasthenia gravis

Acute exacerbation of generalized myasthenia gravis (GMG) can cause swallowing impairment, respiratory failure, or death. It is important to identify immunological factors that might be regarded reliably as an index of the patient's clinical condition, response to treatment, and measure of certain immune aberrations of MG. In this study we investigated correlations between complement component C3, acetylcholine receptor antibody (AChRab) titer, and clinical severity of GMG. AChRab titer and C3 concentration were determined by radioimmunoassay and nephelometry, respectively. The clinical severity of GMG was assessed by the quantitative MG score (QMGS) according to Besinger and colleagues. Our findings indicate that the C3 level correlates with clinical severity of AChRab‐positive GMG. Muscle Nerve, 2009     

眼肌型及全身型重症肌无力患者外周血T淋巴细胞Fas的表达

目的 探讨Fas介导的细胞凋亡与眼肌型(ocular myasthenia gravis,OMG)及全身型重症肌无力(generalized myasthenia gravis,GMG)发病的关系.方法 采用流式细胞技术检测4例OMG、13例GMG患者及13例健康对照组外周血淋巴细胞中CD4、CD8及Fas的表达.结果 OMG、GMG组与对照组外周血T淋巴细胞表面CD4、CD8分子表达的差异无统计学意义(P>0.05).GMG组与对照组外周血T淋巴细胞中Fas+细胞比例的差异有统计学意义(41.72%±8.73%、31.22%±13.00%,P:0.017).GMG组与对照组Fas表达增高者比例的差异有统计学意义(61.5%、15,4%,P=0.041).Fas表达增高的GMG患者病情较重.病程较长.胸腺瘤发生率较高.OMG与GMG组外周血T淋巴细胞中Fa8+、CD4+Fas+、CD8+Fas+细胞比例差异无统计学意义(P>0.05).结论 GMG患者外周血T淋巴细胞中Fas的表达升高,OMG与GMG患者外周血T淋巴细胞中Fas的表达无显著差异,二者可能同属一种系统性疾病.     

Association of HLA-Bw46DR9 combination with juvenile myasthenia gravis in Chinese.

One hundred and fifty two Chinese patients with myasthenia gravis in Taiwan were investigated for HLA-A, B, C and DR/DQ typing. HLA-Bw46 and DR9 frequencies were significantly increased in patients compared with the control group, and there was a decrease in DR3. Further analysis between different subgroups of patients showed Bw46 and DR9 were more significantly increased in the juvenile group than in the adult group. No single HLA allele was associated with either clinical type or thymic pathology, but there was an excess of BW46DR9 combination in both juvenile and ocular type patients. The Chinese population with myasthenia gravis is characterised by earlier age at onset, more ocular forms and less clinically severe illness than in whites, and these characteristics indicate a special subgroup that correlates with the strong Bw46DR9 association.     

Myasthenia induced by D-penicillamine. Apropos of 2 case reports

Two cases of penicillamine-induced myasthenia gravis in rheumatoid polyarthritis are reported. A complete recovery was obtained in both cases. The authors discuss the clinical presentation and the pathogenetic mechanisms of that drug-induced myasthenia gravis. The presence in both cases of both the HLA antigens DR1 and BW35 is emphasized.     

Familial autoimmune myasthenia gravis and thymoma: occurrence in two brothers

At ages 31 and 42 years, two brothers presented with clinical, pharmacologic, electrophysiologic, and immunologic characteristics of autoimmune myasthenia gravis. At thymectomy, both had histologic findings of epithelial thymoma. HLA analysis revealed A2, A3, B7, and B39 antigens in one patient and A3, A24, B7, and B40 antigens in the other. Familial myasthenia gravis with thymoma has not been described previously. Familial thymoma has been rarely reported, but never with myasthenia gravis.     

T suppressor cell function in patients with myasthenia gravis

The activities of Con A-induced Suppressor Cells (Con-ASC) were determined in 50 patients with myasthenia gravis (MG) and 24 healthy controls. The ConA-SC activity of the patients with MG was significantly decreased as compared with that of the controls (10.06%) versus 25.28%, (P less than 0.01). Furthermore, the patients with generalized myasthenia gravis (GMG) had a lower ConA-SC activity than those with extraocular muscle myasthenia gravis (EMMG) (9.37% versus 12.13%, P less than 0.05), but their serum anti-acetylcholine receptor antibody titer was higher than that of patients with EMMG (20.55 x 10(-9) M versus 2.4 x 10(-9) M, P less than 0.01). No correlation found between the ConA-SC activity and the sex or duration of disease of the MG patients. And no effects of prednisone and thymectomy were found on the ConA-SC activity of MG patients. The results of the study suggested that the decreased function of suppressor T lymphocytes might play an important role in the pathogenesis of MG.     

重症肌无力患者HLA-B易感基因研究

目的探讨中国汉族重症肌无力(MG)患者及其不同亚型与人类白细胞抗原(HLA)-B等位基因的相关性。方法应用聚合酶链反应-序列特异性的寡核苷酸探针杂交法(PCR-SSOP)对91例中国汉族MG患者及171名健康对照者进行HLA-B等位基因分型,并采用病例-对照研究及显性遗传模式的方法系统分析HLA-B等位基因与MG患者不同临床亚型之间的相关性。结果按照性别、年龄、临床类型、抗乙酰胆碱受体(AChR)抗体及胸腺病变将患者组分为不同亚型后,结果显示HLA-B*46阳性率在男性、眼肌型、抗AChR抗体阴性及伴发胸腺瘤组中升高,HLA-B*08阳性率在早发型及全身型患者组中升高。与对照组比较,患者组HLA-B*35和B*38阳性率降低。结论 HLA-B*46基因可能是男性、眼肌型、抗AChR抗体阴性及伴发胸腺瘤的MG患者的易感基因或与易感基因相连锁;HLA-B*08可能是早发型及全身型MG患者的易感基因或与易感基因相连锁。HLA-B*35和B*38可能是MG的保护基因或与保护基因相连锁。     

HLA and acetylcholine receptor antibody in patients with myasthenia gravis]

Human leucocyte antigen (HLA) and acetylcholine receptor antibody (AchRab) titer in the serum assayed were in 106 and 100 patients with myasthenia gravis (MG), respectively. 93 of the total patients had both HLA and AchRab assays. There is a strong association between HLA Bw46, Cx46 antigens and the patients with MG. The AchRab level in the patients with positive Bw46, Cx46 antigen is significantly lower than that of the patients with negative Bw46 Cx46 antigen. The geometric means (G) of AchRab were 2.99 and 4.74, respectively, P less than 0.05. From our study, We think the patients with MG could be divided into two groups, according to the clinical presentation, the AchRab level and the association with HLA Bw46, Cx46 antigens. The first group is that who present ocular muscular myasthenia, childhood or adolescence onset, lower level of AchRab titer and strong association with HLA Bw46 and Cx46. The second one is that who have general muscular myasthenia, adult onset, higher level of AchRab titer and no association with Bw46 and Cx46.     

Ocular myasthenia gravis in a senior population: Diagnosis,therapy, and prognosis

The objectives of this study were (I) to explore the prognosis of ocular myasthenia gravis (OMG) in patients with onset at age 70 years and above (i.e. senior persons); (2) to identify predictors of secondary generalization in this age group; and 3) to address the effects of immunotherapy on this population of patients. We performed a retrospective analysis of 39 patients with myasthenia gravis who presented with only ocular signs and symptoms after age 70 years. Generalized myasthenia gravis (GMG) developed in 12 OMG patients (31%). None of the GMG patients required ventilator assistance or a feeding tube. Of the 12 ocular patients progressing to GMG, only one (8%) received immunotherapy prior to generalization. Of those OMG patients who did not progress to GMG, 52% received immunomodulatory therapy. Our senior OMG patients had a prognosis comparable with those of the published data for younger individuals. Although the presence of increased acetylceholine receptor antibody titers and occasionally abnormal repetitive nerve stimulation were useful tools to diagnose OMG, no test was predictive of later generalization. Senior onset OMG patients who received immunotherapy less frequently developed GMG than those not so treated. Muscle Nerve, 2010     

Familial myasthenia gravis.

A family is reported in which myasthenia gravis and thyroid disease occur over three generations. The grandmother and granddaughter have ocular myasthenia and an aunt in the second generation had generalised myasthenia gravis with a thymoma. The pattern of histocompatibility antigens (HLA) haplotypes, anti-AChR antibodies, anti-striate muscle antibodies and thyroid disease is described. The haplotype HLA-A1, B8 was found in affected members of the first and third generation but the family study showed that this was not the same haplotype because the HLA-A1, B8 haplotype in the third generation was contributed by an unaffected person marrying into the family in the second generation.