Fig. 2. DSS-induced colitis in bone marrow–chimeric mice generated from WT and H4R−/− mice. Recipient mice were lethally irradiated, transplanted with bone marrow cells from syngenic or allogenic donors, and then subjected to DSS-induced colitis (start of DSS feeding = day 0). (A) Clinical symptoms of colitis (body weight, perannal bleeding, stool consistency) were evaluated daily in a quantitative manner and summed up into a disease activity index (DAI). *WT→WT vs. WT→H4R−/−; #WT→ H4R−/− vs. WT→ H4R−/−; */#P < 0.05; Kruskal-Wallis rank sum test with Dunnett’s post test. (B) After the observation period, the cola of the mice were prepared and submitted to histologic analyses. Signs of inflammation were quantitatively evaluated and summed up into a TJL score. *P < 0.05; Kruskal-Wallis rank sum test with Dunnett’s post test. WT→WT, WT donor, WT recipient; H4R−/−→WT, H4R−/− donor, WT recipient; WT→H4R−/−, WT donor, H4R−/− recipient; H4R−/−→H4R−/−, H4R−/− donor, H4R−/− recipient; n = 9–10.