Researchers explored the role of gut microbiota in patients with psoriatic arthritis (PsA), particularly those presenting with enthesitis and dactylitis, compared to patients with undifferentiated arthritis lacking these features (NO PsA). Using 16S rRNA sequencing, researchers analyzed fecal samples from 9 patients with PsA and 10 patients with NO PsA, excluding those with other defined autoimmune diseases. While standard clinical lab tests could not distinguish between the groups, microbiome analysis revealed notable differences. Specifically, Megasphaera elsdenii was found at levels 10,000 times higher in PsA patients, while the family XIII_AD3011 was more prevalent in the NO PsA group.

The findings suggest that gut microbiota composition is more closely associated with the presence of enthesitis and dactylitis than conventional serum markers. Patients with PsA exhibited greater microbial homogeneity within the group and higher heterogeneity when compared to NO PsA patients. These microbial signatures, particularly Megasphaera elsdenii and Bifidobacterium longum (the latter showing a negative correlation with eosinophils), may serve as potential biomarkers for differentiating PsA from other forms of arthritis. A larger study with deeper biochemical analysis is recommended to validate these preliminary results and further explore the gut-joint axis in inflammatory arthritis.

Reference: Lin CY, Hsu CY, He HR, et al. Gut microbiota differences between psoriatic arthritis and other undifferentiated arthritis: A pilot study. Medicine (Baltimore). 2022 Jul 15;101(28):e29870. doi: 10.1097/MD.0000000000029870. PMID: 35839060; PMCID: PMC11132366.