Transplantation of HLA Haploidentical Marrow Cells After Ex Vivo Exposure to Recipient Alloantigen in Presence of CTLA4-Ig - A Phase II Study of Tolerance Induction in Donor T Cells by Blockade of the CD80/CD86:CD28 Costimulatory Signal

OBJECTIVES: I. Determine the incidence and severity of acute graft versus host disease after transplantation of HLA haploidentical bone marrow preincubated with alloantigen and CTLA4-Ig ex vivo in patients with hematologic malignancies. II. Determine the engraftment rate with this treatment regimen in these patients. III. Determine the safety of this treatment regimen in these patients. IV. Determine the incidence of infection and relapse after this treatment regimen in these patients. V. Determine whether host specific tolerance develops in these patients after receiving this treatment regimen.

OUTLINE: This is a multicenter study. Patients undergo leukapheresis to collect white blood cells which are incubated with donor bone marrow cells in the presence of CTLA4-Ig for 36 hours. Patients undergo total body irradiation on days -7, -6, -5, and -4 and receive cyclophosphamide IV on days -3 and -2. Patients with acute lymphocytic leukemia, prior lymphoid blast crisis chronic myelogenous leukemia, high grade non-Hodgkin's leukemia (NHL), intermediate grade NHL with prior marrow or extramedullary disease, or prior CNS leukemia receive 2 doses of methotrexate intrathecally prior to bone marrow transplantation, and 4-6 doses following. Patients receive bone marrow transplantation on day 0; methotrexate IV on days 1, 3, 6, and 11; and cyclosporine IV on days -1 to 50. Patients are followed weekly for 1 month, monthly for 2 years, and then annually thereafter.

PROJECTED ACCRUAL: A total of 30 patients will be accrued for this study over 1-2 years.