Consistent with our study, Spoerl et al. recently demonstrated that INCB018424 was able to reduce established GVHD of 6/6 patients treated [13], suggesting that blockade of JAK1/JAK2 would be an effective therapeutic strategy for established GvHD as well as a rational approach as GvHD prophylaxis. The gene discussed is JAK1; the disease is graft versus host disease.