Gut microbiome alterations and its link to corticosteroid resistance in immune thrombocytopenia.

Quantitative metagenomic studies have linked the gut microbiota to autoimmune disorders. Here, we performed deep shotgun metagenomic sequencing of fecal samples from 99 immune thrombocytopenia (ITP) patients and 52 healthy controls. Dysbiosis in the gut microbiome of ITP was detected phylogenetically and functionally, and classifier based on species markers distinguished individuals with ITP from healthy controls. In particular, the abundance of Ruminococcus gnavus, Bifidobacterium longum and Akkermansia muciniphila was markedly increased in treatment-naïve ITP patients, and the alterations of microbial species were correlated with clinical indices. Functionally, the secondary bile acid biosynthesis and flagellar assembly were depleted in the gut microbiota of ITP, which may contribute to the onset of ITP by affecting the immune system. Furthermore, we found that corticosteroid treatment affected the gut microbiome of ITP. Compared with corticosteroid-sensitive ITP patients, we identified that the corticosteroid-resistant ITP patients displayed a distinct gut microbiome, which was different from that of the treatment-naïve ITP patients. Together, we provided support for the critical role of gut microbiota in the development of ITP and established a foundation for further research characterizing gut microbiota in relation to corticosteroid resistance of ITP.