For IL-12 and IL-4 levels in the intestinal mucosa, no significant differences were noted in PI-IBS patients (0.24 ± 0.01 for IL-12 and 0.33 ± 0.02 for IL-4) compared to non-PI-IBS patients (0.22 ± 0.01 for IL-12 and 0.31 ± 0.02 for IL-4) or healthy people (0.22 ± 0.02 for IL-12 and 0.33 ± 0.02 for IL-4) (all P > 0.05), or between the non-PI-IBS and control groups (P > 0.05). Here, IL4 is linked to irritable bowel syndrome.