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Gut levels of IL-9, Th9 may be markers in patients with PsA
A recently published study showed interleukin-9 and T helper 9 cells identified in the gut microbiome of patients with psoriatic arthritis and may play a role in in the disease.
Researchers enrolled 25 patients with psoriatic arthritis (PsA), 15 patients with HLA-B27-positive ankylosing spondylitis (AS) without gastrointestinal symptoms, 10 patients with Crohn’s disease (CD) and 20 healthy individuals. Five patients with active PsA and five patients with end-stage osteoarthritis (OA) undergoing knee joint replacement provided synovial tissue samples.
Histological analysis revealed an association between interleukin-9 (IL-9) and T helper (Th) 9 (Th9) cells. Patients with PsA and subclinical gut inflammation were more likely to have Th17 and Th22 cells present, but not Th1. Significant up-regulation of IL-9 was observed in patients with PsA, but not in patients with CD or AS. Patients with PsA had higher levels of IL-9-producing CD4+ cells, which correlated with disease activity. In synovial tissue, patients with PsA had strong expressions of IL-9 compared to patients with OA.
“In conclusion, specific histologic and immunologic features seem to characterize the subclinical gut inflammation in patients with PsA,” the researchers wrote. “We also demonstrated that Th1 is predominant in CD but not in spondyloarthritis (AS and PsA), that Th17/22 expression is increased in all three diseases, and most importantly, that only Th9 cells are specific to PsA. These findings suggest that IL-9 and Th9 cells may play a role in driving local and systemic inflammation in PsA and might be considered as a potential future therapeutic target.”
Disclosures: Ciccia reports consulting fees from Janssen, Pfizer, Novartis and AbbVie. Please see the full study for a list of all other authors’ relevant financial disclosures.