RecruitingPhase 2Drug trialFaecal Microbiota Transplantation After Allogeneic Stem Cell TransplantationThe aim of this study is to assess the Fecal Microbiota Transplantation (FMT) efficacy in the prevention of allogeneic hematopoietic stem cell transplantation (allo-HSCT) complications and particularly Graft versus Host Disease (GvHD). The hypothesis of this study is that allogeneic FMT may improve outcomes of these patients.