Significant decreases in the expression of the ATF-6, XBP-1, EIF-2-AK, DNAJC-9, and NF-2L-2 mRNAs were observed in blood samples from female patients; in the expression of the ATF-6, XBP-1, EIF-2-AK, DNAJC-9, ERN-1, and NF-2-L-2 mRNAs in blood samples from HP-positive patients; in the expression of the ATF-6, XBP-1, DNAJC-9, and NF-2-L-2 mRNAs in patients without esophagitis in the endoscopic examination; and in the expression of the ATF-6, XBP-1, EIF-2-AK, DNAJC-9, and NF-2-L-2 mRNAs in patients with wild-type CYP2C19. The gene discussed is XBP1; the disease is esophagitis.