GRAFT FAILURE AFTER T-CELL DEPLETED HLA IDENTICAL ALLOGENEIC BONE-MARROW TRANSPLANTATION - RISK-FACTORS IN LEUKEMIC PATIENTS

In a retrospective analysis of T cell depleted bone marrow transplanta tion, we have looked at different parameters in order to determine ris k-factors of graft-failure after allogeneic bone marrow transplantatio n for leukemia. Fifty-one patients with acute leukemia or chronic myel oid leukemia have been analysed. For 33 of them, the pretransplant con ditioning regimen consisted of fractionated total body irradiation (TB I) at 12 Gy prior to cyclophosphamide (120 mg/kg). The other patients received various reinforced preparative regimens. T-cell depletion con sisted of treating marrow cells with pan-T monoclonal antibodies (CD2CD3 or CD2-CD5-CD7) followed by complement mediated cytolysis. No post -transplant immunosuppressive prophylaxis was administered except for the first nine patients who received Methotrexate alone. In this group of 51 patients, 12 died within 3 months from graft-related complicati ons and 10 developed graft failure (no engraftment or rejection). Amon g the possible risk factors associated with this failure, two graft-re lated parameters appeared significant: the number of CFU-GM progenitor s and the number of viable T cells injected with the marrow inoculum. No correlation with graft failure was found with other parameters incl uding diagnosis, disease status at transplant, conditioning regimen, a ge, sex, and CMV status of donor/host pairs. However, the interpretati on must remain cautious because of the relatively small samples in eac h group.