CRP and irritable bowel syndrome: There were no significant differences in IgA (IBS median, 223.3 mg/dL vs. HC median, 241.6 mg/dL; p = 0.3087), IgG (IBS median, 1165 mg/dL vs. HC median, 1206 mg/dL; p = 0.2106), IgM (IBS median, 150.2 mg/dL vs. HC median, 141.7 mg/dL; p = 0.8736), RF (IBS median, 7 UI/mL vs. HC median, 9.2 UI/mL; p = 0.0612) and CRP (IBS median, 0.2 mg/dL vs. HC median, 0.1 mg/dL; p = 0.1014) serum levels between IBS patients and HC group (Figure 1).