AUTHOR=Ren Jingru , Wang Jianchun , Liu Ran , Guo Jing , Yao Yan , Luo Jingjing , Hao Hongjun , Gao Feng TITLE=Case report: Persistent hypogammaglobulinemia in thymoma-associated myasthenia gravis: the impact of rituximab or Good's syndrome? JOURNAL=Frontiers in Neurology VOLUME=Volume 14 - 2023 YEAR=2023 URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1152992 DOI=10.3389/fneur.2023.1152992 ISSN=1664-2295 ABSTRACT=Introduction: Rituximab (RTX) showed good efficacy and safety for patients with myasthenia gravis. However, the percentage of peripheral CD20+ B cell may be absent for years after low dose of RTX treatment. Persistent hypogammaglobulinemia and opportunistic infection may occur in patients under treatment of RTX with thymoma relapse. Case representation: We report a case of refractory myasthenia gravis. After two doses of 100 mg rituximab, the patient developed transient neutropenia. The peripheral blood CD20+ B cell percentage was 0 more than three years. 18 months later, the patient’s symptoms relapsed with thymoma recurred. She had persistent hypogammaglobulinemia and multiple opportunistic infections. Conclusion: In MG patient under B cell depletion therapy had thymoma relapse, Good's syndrome may induce prolonged B cell depletion, hypogammaglobulinemia and opportunistic infections.