IL22 and fibrosis: This is likely owing to the fact that some groups have focused on the initial ALI/ARDS phase of disease,44 whereas others have investigated the role of IL-22 in fibrosis.54, 55, 56, 57 This study showed that IL-22 is produced early after bleomycin challenge and, if it is unabated, as in Il22ra2−/− mice, there is robust inflammation.