Fecal microbiota analysis in children with oligoarticular juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic and heterogeneous rheumatic disease of childhood, with an etiology that has not yet been fully elucidated. The diagnostic criteria for JIA include arthritis of one or more joints that begins before the age of sixteen, persists for more than six weeks, and cannot be explained by other identifiable causes of joint inflammation. Multiple factors are thought to contribute to the etiopathogenesis of the disease. The microbiota refers to the community of microorganisms including bacteria, viruses, bacteriophages, fungi, and archaea. Alterations in microbial composition may increase susceptibility to JIA through various mechanisms. This study aimed to comparatively evaluate the fecal microbiota components of children with oligoarticular JIA receiving biological agents, those not receiving biological agents, and healthy children, and to elucidate the relationship between microbiota, disease pathogenesis, and treatment agents in light of the current literature. This prospective, single-center study included 22 children with oligoarticular JIA receiving biological therapy, 22 not receiving biological therapy, and 24 healthy controls. The intestinal microbiota composition was analyzed using advanced metagenomic methods. In our study, Bacteroidaceae, Parabacteroides, Erysipelotrichia–Erysipelotrichales, Bacteroides, and Alistipes were found to be more abundant in JIA patients compared to healthy controls. The Firmicutes/Bacteroidetes (F/B) ratio, Erysipelotrichaceae, Gemellaceae, Ruminococcaceae, Bifidobacterium, Streptococcus, F. prausnitzii, Bacteroides fragilis, Gemmiger formicilis, Dorea formicigenerans, and Veillonella dispar were more abundant in healthy controls than in JIA patients. Dialister, Lachnospiraceae, and Akkermansia muciniphila were more abundant in patients receiving biological therapy, whereas Alistipes putredinis was more abundant in patients not receiving biological therapy. More comprehensive studies are needed to clarify how these microbiota alterations relate to the development and course of JIA, as well as to the mechanisms of action of therapeutic agents. Keywords: Juvenile idiopathic arthritis, JIA, child, microbiota, microbiome, biological agent