Ruxolitinib treatment reduces GVHD severity in mice. (A) Survival of recipient BALB/c mice, after allo-HCT. Survival was improved in ruxolitinib-treated mice compared with vehicle-treated mice. The experiment was performed twice and the resulting data were pooled. The number of mice is indicated for each group. (B) Weight ratio (actual weight/initial weight) of recipient BALB/c mice, after allo-HCT as described in (A). (C) A representative section of a colon isolated on d8 after allo-HCT from mice treated as described under (A) is shown. Red arrows indicate crypts containing karyorrhectic debris. Blue arrows: goblet cells, absence of apoptotic bodies in the ruxolitinib treated mouse. (D) The organs small intestine, large intestine, and liver were isolated on days 8, 14, and 29 after allo-HCT, and histopathologic changes were scored as described in Material and methods. The data are pooled from 2 independent experiments with at least 6 mice per group.