 RATIONALE: Giving chemotherapy and total-body irradiation before a donor peripheral blood stem cell transplant helps stop the growth of cancer cells. It also stops the patients immune system from rejecting the donors stem cells. The donated stem cells may replace the patients immune cells and help destroy any remaining cancer cells graft-versus-tumor effect. Sometimes the transplanted cells from a donor can also make an immune response against the bodys normal cells. Giving tacrolimus, sirolimus, antithymocyte globulin, and methotrexate before and after transplant may stop this from happening. 