V. To determine the effect of rituximab addition to the conditioning regimen on antigen presenting myeloid cell recovery, and to determine the effect of dendritic cell subset DC1, DC2 and myeloid-derived suppressor cells (MDSC), number in the stem cell graft and at day +30 on the incidence of acute GVHD grade II-IV and the cumulative incidence of infectious complications at day 100.