OBJECTIVES: I. Determine if megadose CD34 cells and intense immunosuppression administered before and after partially matched related donor (PMRD) hematopoietic stem cell (HSC) transplantation results in engraftment in patients with high risk hematologic malignancies. II. Determine the incidence and severity of acute grade (I-IV) and chronic (limited or extensive) graft versus host disease in patients after rigorous T-cell depletion in PMRD HSC transplantation.