Rituximab-induced gut microbiota changes in Chinese neuromyelitis optica spectrum disorders.

BACKGROUND: Recent evidence shows that immunosuppressive agents can affect the gut microbiota in autoimmune diseases. However, the relationship between the gut microbiome and B-cell depletion immunotherapy in neuromyelitis optica spectrum disorder (NMOSD) remains poorly understood.

OBJECTIVES: To evaluate the distinct intestinal microbial patterns and serum cytokine levels after short-term rituximab treatment (three months) in patients with NMOSD.

METHODS: Firstly, we conducted a cross-sectional study involving 46 treatment-naïve NMOSD patients and 48 matched healthy controls. We collected fecal specimens, which were then analyzed using next-generation sequencing, and quantified serum cytokines. Subsequently, fecal and serum samples were re-collected and re-evaluated in 31 of the 46 treatment-naïve NMOSD patients after RTX treatment.

RESULTS: Comparing the gut microbiome of treatment-naïve NMOSD patients to that of healthy controls revealed low α-diversity and distinct microbial compositions in the former. The microbial composition in NMOSD patients underwent changes following three months of RTX treatment. Specifically, the levels of IL-17F and IL-6 decreased, while those of IL-10 and TNFα increased after RTX treatment. LEfSe analysis identified 27 KEGG categories with significantly differential abundances between NMOSD patients and RTX treatment group.

CONCLUSIONS: Our study provides a comprehensive understanding of the gut microbiota landscape in the context of B-cell depletion immunotherapy. We observed dysbiosis in the gut microbiome of NMOSD patients, which was partially alleviated by three months of RTX treatment. This suggests that B-cell depletion may play a crucial role in driving changes in the gastrointestinal environment.