Myasthenia gravis: Predictive factors associated with the synchronized elevation of anti-acetylcholine receptor antibody titer in Kanazawa, Japan

• The increased event of anti-AChR Ab titer was seen in 2012 at a local area in Japan.
• We examined the predictive factors associated with this incidence in MG patients.
• Late-onset MG had a higher incidence of antibody titer elevation than early-onset MG.
• Thymectomy was found to prevent the antibody titer elevation in non-thymoma MG.
• We speculated that this incidence was due to a potential environmental trigger.

For a brief period, an increased incidence of elevated anti-acetylcholine receptor antibody titer was observed in patients with myasthenia gravis (MG) in Kanazawa, Japan. The purpose of this study was to examine the predictive factors associated with this antibody titer elevation. Decreased odds of titer elevation were seen in patients with early-onset MG than in those with late-onset MG. In patients with non-thymoma-related MG, thymectomy prevented the antibody titer elevation. Our data suggest that late-onset MG may have a different immunogenic response and the thymus might play an immunoregulatory role against extrinsic factors in some types of MG.