IL33 and chronic gastritis: If the mean of IL-33 mRNA level in chronic gastritis group is 0.0031 and the mean of IL-33 mRNA level in active gastritis group is 0.0083 then the difference in the IL-33 mRNA expression in the active gastritis compared with the chronic gastritis biopsies is 0.0083/0.0031 or 2.67 fold (Fig. 3).