As example, it has been shown that tacrolimus (given in patients included in the current study) decreased T cell proliferation induced by IL-7 [59], and tacrolimus levels were kept high in our patients the first weeks after transplantation (median 18.6, 16.4, 14.9 and 14.3 μg/L on days 0, 7, 14 and 21 after transplantation, respectively) probably explaining the low relatively incidence of acute GVHD observed [60]. Here, IL7 is linked to acute graft versus host disease.