Much uncertainty still exists about the viral etiology of myasthenia gravis (MG). To address this, we explored the relationship between human parvovirus B19 (PVB19) infection and MG by investigating the presence of PVB19-specific antibodies in serum. A total of 131 patients with MG (including 47 with thymoma-associated MG, 14 with hyperplasia-associated MG, and 70 with unknown thymic lesions) and 172 healthy volunteers were enrolled in this study. Enzyme linked immunosorbent assay was conducted to detect virus-specific antibodies in cell-free serum. The data were analyzed using Pearson chi-square (χ²) and Fisher's exact tests. In the 131 patients with MG, there was no significant difference between male (53.41 ± 14.65 years) and female (50.19 ± 15.28 years) groups regarding mean age (p > 0.05). Among all MG subgroups, the largest age group comprised participants aged 30–60 years. We found that the frequency of detecting immunoglobulin G (IgG) antibodies against PVB19 VP1 and VP2 was significantly higher among patients with MG (68.70%) than in healthy controls (41.86%) (p < 0.001). In particular, the positive rate for anti-PVB19 IgG in patients with thymoma-associated MG (35/47, 74.47%) was significantly higher than that in healthy participants (72/172, 41.86%; p < 0.001). The findings of this study indicate that PVB19 infection may play a role in the etiopathogenesis of MG, particularly in patients with thymoma-associated MG. The study protocol was registered at ClinicalTrials.gov with the identifier ChiCTR-1900023338.

中文翻译：

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胸腺瘤相关重症肌无力患者血清中人细小病毒B19 IgM和IgG抗体的检测

重症肌无力 (MG) 的病毒病因仍然存在很多不确定性。为了解决这个问题，我们通过调查血清中 PVB19 特异性抗体的存在来探索人类细小病毒 B19 (PVB19) 感染与 MG 之间的关系。共有 131 例 MG 患者（其中 47 例胸腺瘤相关 MG，14 例增生相关 MG，70 例胸腺病变未知）和 172 名健康志愿者参加了本研究。进行酶联免疫吸附测定以检测无细胞血清中的病毒特异性抗体。使用 Pearson 卡方 ( χ ² ) 和 Fisher 精确检验分析数据。在 131 例 MG 患者中，男性（53.41 ± 14.65 岁）和女性（50.19 ± 15.28 岁）组的平均年龄无显着差异（p  > 0.05)。在所有 MG 亚组中，最大的年龄组包括 30-60 岁的参与者。我们发现，MG 患者（68.70%）检测到针对 PVB19 VP1 和 VP2 的免疫球蛋白 G（IgG）抗体的频率显着高于健康对照组（41.86%）（p  < 0.001）。特别是胸腺瘤相关性MG患者抗PVB19 IgG的阳性率（35/47，74.47%）明显高于健康参与者（72/172，41.86%；p  < 0.001）。这项研究的结果表明，PVB19 感染可能在 MG 的发病机制中发挥作用，特别是在胸腺瘤相关 MG 患者中。该研究方案在 ClinicalTrials.gov 注册，标识符为 ChiCTR-1900023338。