Preliminary insights into the gut microbiota of patients with rheumatoid arthritis in Vietnam

In Vietnam, rheumatoid arthritis accounts for more than 20% of all joint diseases, with a growing number of young patients. The disease progresses rapidly, but its exact cause remains not fully understood. Environmental and lifestyle factors, such as smoking, pollution, obesity, gut microbiota, and infections, play a role in rheumatoid arthritis development. The presence of Gram-positive bacteria in the gut might promote the release of toxic metabolites into the bloodstream, which in turn triggers joint inflammation. Therefore, this pilot study aimed to compare the gut microbiota in 22 patients with newly diagnosed rheumatoid arthritis and 20 healthy individuals recruited at the Bach Mai Hospital, Hanoi, Vietnam. To this end, we analyzed fecal samples from all participants by 16S rRNA metagenomic sequencing. The sequencing data analysis did not reveal any significant differences in alpha diversity between patients and healthy controls. Conversely, unweighted and weighted UniFrac distances (beta diversity metrics) allowed distinct clustering between groups. The abundance of the <i>Lactococcus, Solobacterium, Faecalibaculum,</i> and <i>Corynebacterium</i> genera was increased, and that of <i>Bacteroides</i> was decreased in patients with rheumatoid arthritis compared with healthy controls. Moreover, patients exhibited distinct gut microbiota profiles in function of their disease activity scores (DAS28-CRP, DAS-ESR), rheumatoid factor, and anti-citrullinated protein antibody concentrations. Overall, our study contributes to bridging this knowledge gap and provides a foundation for the study of gut microbial signatures of autoimmune disease in Vietnamese patients. It also highlights the potential role of gut microbes in rheumatoid arthritis diagnosis and management in Vietnam.