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Findings suggest gut microbe is immune-relevant in RA pathogenesis
Observations from this study using tissue and peripheral blood mononuclear cell samples indicate Prevotella copri, a gut microbe, is immune-relevant in the pathogenesis of rheumatoid arthritis.
“[Our] study provides evidences for the immune relevance of P. copri in [rheumatoid arthritis] RA and suggests that bowel pathology may be a feature of the disease in this subgroup of patients,” Annalisa Pianta, PhD, at Massachusetts General Hospital and Harvard Medical School, and colleagues wrote.
They extracted T-cell epitopes of P. copri from the synovial tissue or peripheral blood mononuclear cell samples of patients with rheumatoid arthritis (RA). Researchers examined the antigenicity of peptides or their source proteins, T-cell reactivity, antibody responses, cytokine/chemokine determinations, and serum and synovial fluid samples with 16S ribosomal DNA for P. copri.
Researchers identified T-cell epitopes from a 27-kd protein of P. copri which stimulated 42% of patients with recent-onset RA. One subgroup in both patients with recent-onset RA and patients with chronic RA had IgA antibody responses to either Pc-p27 or the entire organism, which associated with Th17 cytokine responses and frequent anti-citrullinated protein antibodies (ACPAs).
“The other subgroup had IgG P copri antibodies, which were associated with Prevotella DNA in synovial fluid, P copri–specific Th1 responses, and less frequent ACPAs,” the authors wrote. In patients with other rheumatic diseases, P. copri antibody responses were “rarely found.”
“[P. copri] IgG antibody responses could provide support for the diagnosis in RA patients who lack ACPA or [rheumatoid factor] RF,” the researchers wrote. “Moreover, dietary interventions or specifically tailored antibiotic regimens targeting P. copri could play an adjunctive role to [disease-modifying antirheumatic drugs] DMARDs in the treatment of this disease.” – by Will Offit
Disclosures: The researchers report support by the ACR, the Ounsworth-Fitzgerald Foundation, the Mathers Foundation, the English-Bonter-Mitchell Foundation, the Littauer Foundation, the Lillian B. Davey Foundation, the Eshe Fund and the NIH.