Ryotaro Ikeguchi1, Yuko Shimizu2, Shigeaki Suzuki3, Satoru Shimizu4, Chiaki Kabasawa2, Shiori Hashimoto2, Masayuki Masuda5, Yuriko Nagane6, Kimiaki Utsugisawa6, Yasushi Suzuki7, Toshiyuki Takahashi8, Hiroya Utsumi9, Kazuo Fujihara8, Norihiro Suzuki3, Shinichiro Uchiyama2. 1. Department of Neurology, Tokyo Women's Medical University School of Medicine, Tokyo, Japan. Electronic address: riker1013@yahoo.co.jp. 2. Department of Neurology, Tokyo Women's Medical University School of Medicine, Tokyo, Japan. 3. Department of Neurology, Keio University School of Medicine, Tokyo, Japan. 4. Medical Research Institute, Tokyo Women's Medical University, Tokyo, Japan. 5. Department of Neurology, Tokyo Medical University, Tokyo, Japan. 6. Department of Neurology, Hanamaki General Hospital, Iwate, Japan. 7. Department of Neurology, National Hospital Organization Sendai Medical Center, Sendai, Japan. 8. Department of Neurology, Tohoku University Graduate School of Medicine, Sendai, Japan. 9. Department of Neurology, Kamata General Hospital, Tokyo, Japan.
Abstract
BACKGROUND: The incidence of concurrent myasthenia gravis (MG) and neuromyelitis optica spectrum disorder (NMOSD) is higher than what chance predicts, yet it remains unclear why MG and NMOSD appear concurrently. OBJECTIVE: The purpose of the present study was to examine the clinical features of the concurrence of these diseases. METHODS: Clinical details were analyzed retrospectively. RESULTS: Three (0.5%) out of 631 MG patients had confirmed (n=2) or suspected (n=1) NMOSD. Two of these patients were women. All showed early-onset MG (EOMG) that preceded NMOSD and were positive for acetylcholine receptor antibody (AChR-Ab). Two patients were tested for aquaporin 4 antibody (AQP4-Ab) and were positive. Two patients were treated with a thymectomy that preceded NMOSD. Two patients had decreased frequency of regulatory T (Treg) cells. We identified in the literature 46 patients with both MG and NMOSD. Our results of female predominance, EOMG, MG preceding NMOSD, and positive AChR-Ab are consistent with previous descriptions. CONCLUSIONS: This is the first report to examine the frequency of NMOSD in Japanese patients with MG. The reduction and/or dysfunction of Treg cells may be one cause of NMOSD development in MG.
BACKGROUND: The incidence of concurrent myasthenia gravis (MG) and neuromyelitis optica spectrum disorder (NMOSD) is higher than what chance predicts, yet it remains unclear why MG and NMOSD appear concurrently. OBJECTIVE: The purpose of the present study was to examine the clinical features of the concurrence of these diseases. METHODS: Clinical details were analyzed retrospectively. RESULTS: Three (0.5%) out of 631 MGpatients had confirmed (n=2) or suspected (n=1) NMOSD. Two of these patients were women. All showed early-onset MG (EOMG) that preceded NMOSD and were positive for acetylcholine receptor antibody (AChR-Ab). Two patients were tested for aquaporin 4 antibody (AQP4-Ab) and were positive. Two patients were treated with a thymectomy that preceded NMOSD. Two patients had decreased frequency of regulatory T (Treg) cells. We identified in the literature 46 patients with both MG and NMOSD. Our results of female predominance, EOMG, MG preceding NMOSD, and positive AChR-Ab are consistent with previous descriptions. CONCLUSIONS: This is the first report to examine the frequency of NMOSD in Japanese patients with MG. The reduction and/or dysfunction of Treg cells may be one cause of NMOSD development in MG.