Overall, up- and downregulated mRNA expressions of 21 genes (P = 10(-5) to 10(-8); P values with false detection rates are shown) were potentially relevant to IBS-D including the following: neurotransmitters [P2RY4 (P = 0.001), vasoactive intestinal peptide (VIP, P = 0.02)]; cytokines [CCL20 (P = 0.019)]; immune function [C4BPA complement cascade (P = 0.0187)]; interferon-related [IFIT3 (P = 0.016)]; mucosal repair and cell adhesion [trefoil protein (TFF1, P = 0.012)], retinol binding protein [RBP2 (P = 0.017)]; fibronectin (FN1, P = 0.009); and ion channel functions [guanylate cyclase (GUCA2B, P = 0.017), PDZ domain-containing protein 3 (PDZD3, P = 0.029)].