Accumulating studies have demonstrated that gut microbial dysbiosis can occur in RA patients compared to healthy individuals, but differences in gut microbial compositions were also observed among RA patients with different clinical phenotypes, such as ACPA seropositivity and cytokine levels (TNF-α, IL-6, and IL-17A) (8, 9). Here, PRTN3 is linked to rheumatoid arthritis.