Background: Reduced intensity conditioning before allogeneic stem cell transplantation is an option for patients not eligible for myeloablative standard procedure. In recent years alemtuzumab, an anti CD52 antibody has gained much interest in this setting for its particular immunosuppresive properties.
Material/Methods: We evaluated clinical results of allogeneic stem cell transplantation in nine patients (2 females and 7 males, median age 51, range 26-65) after reduced intensity conditioning consisting of busulfan, cladribine and alemtuzumab. The donors were HLA identical siblings (7) or unrelated (2). Peripheral blood stem cells mobilized with G-CSF were used. Cyclosporine alone was used for GvHD prevention after transplantation.
Results: 4 patients (44%) are alive at 24-42 months after transplantation and 3 patients (33%) remain in complete remission at 26-42 months, including one after donor lymphocyte infusion for decreasing hematopoietic chimerism. No acute graft versus host disease was observed and only 3 patients (33%) developed chronic graft versus host disease. High rate (56%) of CMV reactivation and 2 cases of tuberculosis were noted. All deceased patents died due to disease relapse and progression.
Conclusions: Reduced intensity conditioning with alemtuzumab and allogeneic stem cell transplantation offers potential cure to patients not eligible for conventional procedure. Better methodology of chimerism evaluation is mandatory to improve results of transplantations by implementation donor lymphocyte infusions.

Keywords: Stem Cell Transplantation, reduced intensity conditioning, alemtuzumab