Efficacy of Low-Dose Rituximab in Treating Myasthenia Gravis Patients Positive for AChR Antibodies or MuSK Antibodies

doi:10.3969/j.issn.1674-3245.2025.03.038

Abstract：Objective To observe the effect of low-dose rituximab on patients with myasthenia gravis (MG) who are positive for anti-acetylcholine receptor (AChR) antibodies or muscle-specific receptor tyrosine kinase (MuSK) antibodies. Methods Forty-three MG patients treated at Hankou Hospital, Wuhan from May 2020 to May 2023 were selected. All patients received rituximab at a dose of 375 mg/m² every two weeks for a total of two doses. The therapeutic efficacy was evaluated using the quantitative myasthenia gravis (QMG) scale and the post-intervention status (PIS) classification, and changes in the ratio of CD19+ B cells were detected. Adverse reactions and recurrence rates were recorded during follow-up. Results A total of 43 patients were included in the study, including 34 patients with AChR-MG and 9 patients with MuSK-MG. The baseline QMG score of all patients was (12.06±7.48) points, which decreased to (2.66±2.31) after RTX induction therapy, showing a statistically significant difference (t=7.874, P=0.000). Sixteen patients (37.21%) achieved remission, and 29 patients (67.44%) reached a minimal manifestation state (MMS) or higher. One and six months after treatment, the CD19+ B cell ratio in MG patients was lower than before treatment, with statistically significant differences (Z=2.138, 1.779, P<0.05). The remission rate in MuSK-MG patients according to MGFA-PIS classification was 66.67%, higher than that in AChR-MG patients (29.41%), with a statistically significant difference (x²=4.227, P=0.039). During follow-up of 10–31 months, the overall recurrence rate was 41.86%. The recurrence rate in the AChR-MG group was higher than that in the MuSK-MG group, but the difference was not statistically significant (P>0.05). Conclusion Low-dose rituximab can significantly improve the prognosis of MG patients with mild adverse reactions, and its efficacy is better in MuSK-MG patients than in AChR-MG patients.