IFN-γ^−/−IL-17^−/− donor CD4⁺ T cells induced little tissue damage in gut, liver, and skin, but severe damage in lung. (A-C) Percent survival, percentage of mice with diarrhea, and body-weight change after HCT. There were 12 mice in each group, combined from 3 replicate experiments. (D-E) H&E staining of colon, liver, lung, and skin tissue sections of recipients 20 to 25 days after HCT and mean ± SE of histopathology scores (n = 12).