Evolution of gut microbiota in psoriatic arthritis treated with IL-17 inhibitor revealed by metagenomics.

OBJECTIVES

To explore the evolution of gut microbiota in taxonomy and function in PsA patients during IL-17i treatment.

METHODS

Twenty PsA patients treated with secukizumab were included. Fecal samples were collected before treatment (0 mo.), first month (1 mo.) and third month (3 mo.) after treatment, and a total of 60 samples were collected. Shotgun metagenomic sequencing was used to detect all fecal samples.

RESULTS

In the 1 mo. and 3 mo. after IL-17i treatment, the disease activity in PsA patients decreased significantly. Compared with 0 mo., α-diversity calculated by Shannon index and Pielou index increased significantly at 1 mo. and 3 mo. after treatment. Microbial genes encoding Carbohydrate-Active enZymes (CAZymes) tended to be upregulated after treatment. After treatment, Bacteroidota phylum expanded, especially the abundance of Phocaeicola genus increased gradually with the treatment time (P<0.05). The abundance of Phocaeicola genus was positively correlated with the α-diversity. The Polysaccharide Lyases and Carbohydrate Esterases in CAZymes were significantly positively correlated with most of species in Phocaeicola genus.

CONCLUSIONS

Treatment with IL-17i induces gut microbiota evolution in PsA patients. The key features of this evolution include increased α-diversity, expansion of the Phocaeicola genus, and upregulation of CAZymes. Species within the Phocaeicola genus may be the critical bacteria driving this evolution.