Case reportMemory B cell resurgence requires repeated rituximab in myasthenia gravis

•We examined immunologic reactions in two MG cases treated with rituximab (RTX).•RTX treatment led to sustained clinical improvement.•Disease activity was associated with the repopulation of memory B cells.•Additional RTX should be prescribed upon resurgence of memory B cells.

The immunologic effects of rituximab (RTX) in myasthenia gravis (MG) remain to be explored. We aimed to clarify immunologic reactions and their association with response to RTX in MG. Regulatory T cell and B cell profiles of MG patients were monitored. Two patients presenting with generalized MG with anti-acetylcholine receptor antibodies were treated with RTX. The treatment led to sustained clinical improvement, discontinuation of intravenous immunoglobulin or plasma exchange, and reduction of prednisolone and other drugs. One patient was in remission for more than one year, whereas the other patient exhibited deterioration of symptoms within one year. Disease activity was associated with the repopulation of IgD−CD27− and IgD−CD27+ memory B cells. Clinicians should be aware of the possibility that MG ranges in the duration of B cell depletion and additional RTX should be prescribed upon resurgence of memory B cells.