STAT4 and graft versus host disease: Nikolic and colleagues investigated STAT6-/- and STAT4-/- T cells in a GVHD mouse model and found that STAT6-/- T cell recipients showed an earlier and more severe course of GVHD with severe inflammation in the GI tract in comparison to STAT4-/- T cell recipients, while only the latter group displayed severe skin disorders (107).