 RATIONALE: Giving chemotherapy, such as cyclophosphamide and fludarabine, before a donor stem cell transplant helps to remove the patients cells to allow for the transplant cells to take and grow. It also helps stop the patients immune system from rejecting the donors stem cells. When the healthy stem cells from a donor are infused into the patient, they may help the patients bone marrow make stem cells, red blood cells, white blood cells, and platelets. Sometimes the transplanted cells can make an immune response against the bodys normal cells. Giving antithymocyte globulin and removing the T cells from the donor cells before transplant and giving cyclosporine before and after transplant may stop this from happening. 