Infections and hypogammaglobulinemia in myasthenia gravis patients receiving low-dose rituximab: a real-world cohort study

Aims We investigated the incidence of infections and hypogammaglobulinemia (HGG) in patients with myasthenia gravis (MG) receiving long-term low-dose rituximab (RTX) maintenance therapy and identified related risk factors. Methods This single-center retrospective cohort study enrolled MG patients treated with low-dose RTX maintenance. Cox proportional hazards regression was performed to analyze risk factors for infections and HGG. Results A total of 186 patients were included. The median age at RTX initiation was 52.50 years, and the median follow-up was 2.41 years. Infections occurred in 29 patients (15.59%), with a median time to first infection of 170.37 days, mostly during the first cycle. The 1- and 2-year infection rates were 13.41 (95% confidence interval [CI], 8.47–20.28) and 9.20 (95% CI, 6.06–13.36) per 100 person-years. Severe infections developed in 21 patients (11.29%). The most prevalent infection was lower respiratory tract infection (LRTI), with 19 episodes (61.29%). HGG was present in 51 patients (27.42%). HGG was an independent risk factor for infection (HR = 5.53, P<0.001). Higher baseline prednisone dose (HR = 1.25, P = 0.035) and HGG (HR = 7.50, P<0.001) were significantly correlated with increased risk of severe LRTIs. Conclusion In MG patients receiving long-term low-dose RTX maintenance, the overall infection incidence is relatively low, with LRTIs being the most frequent. HGG is a major independent risk factor for infections and severe LRTIs, while higher baseline prednisone doses were associated with severe LRTIs.