MMRN1 and rheumatoid arthritis: Altogether, 14 of 24 patients (58%) with postinfectious LA had T cell responses to at least 1 ECM peptide compared with borderline positive responses in only 1 of 20 patients (5%) with antibiotic-responsive LA (P = 0.0001) and in only 1 of 9 RA patients (P = 0.02).