Allogeneic bone marrow transplantation (Allo-BMT) can cure many hematological diseases, however it usually comes with a “side effect” that can lead to high levels of morbidity and mortality post transplant, named graft-versus-host disease (GvHD). Until now, much attention has been given to the role of adaptive immunity in GvHD development, however little is known about the involvement of innate immunity, which plays a crucial role in this process, particularly in the first days after BMT. The focus of my research is to evaluate the contribution of pro-inflammatory monocytes to the pathogenesis of GvHD. In parallel, we are also studying the use of mesenchymal stromal cells (MSCs) as an immunosuppressive cell therapy to inhibit and/or control GvHD. Our final goal is to connect both projects by examining how MSCs interact with these pro-inflammatory monocytes in the course of GvHD.