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.
Explore this issueAugust 2017
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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.