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New research reinforces the hypothesis that the gut microbiome triggers mucosal and systemic immune responses in patients with rheumatoid arthritis. The research, published in Arthritis & Rheumatology May 2017, found that subgroups of patients with RA have differential immunoglobulin G (IgG) or IgA immune reactivity with Prevotella copri, an intestinal microbe that appears to be specific for the disease.1 These observations “provide evidence of the immune relevance of P copri in the pathogenesis of RA,” the investigators say.
Lead author Annalisa Pianta, PhD, at Massachusetts General Hospital and Harvard Medical School, says the research she and her colleagues conducted found that about half of patients with RA have T and B cell responses to P copri. Their responses were either IgA antibody responses to P copri, “suggestive of a mucosal immune response, or IgG antibodies to the organism, suggestive of a systemic immune response,” Dr. Pianta says.
For the study, the investigators developed an unbiased, discovery-based approach to identify novel, immunogenic T cell epitopes in patients with chronic inflammatory arthritis. They obtained synovial tissue, synovial fluid mononuclear cells or peripheral blood mononuclear cells from five patients to use for isolation of HLA-DR-presented peptides.