Influence of marrow CFU-GM content on engraftment and survival after allogeneic bone marrow transplantation

The influence of the CFU-GM content of donor marrow on the outcome of allogeneic marrow transplantation (BMT) has been debated. We now report 38 patients (25 acute leukemias, 10 chronic myeloid leukemias, two myeloma; 24 in first CR/CP and 14 in more advanced phases of their disease) undergoing unmanipulated HLA-identical sibling BMT following conditioning with cyclophosphamide and total body irradiation (TBI). The median number of nucleated cells infused was 4.3 x 10(8)/kg (range 1.5-8.4); median CFU-GM numbers were 2.4 x 10(4)/kg (range 0.1-46). End-points of the study were (1) speed of neutrophil and platelet engraftment; (2) quality of engraftment beyond day +50 after BMT; and (3) transplant-related mortality in patients stratified according to whether they had received less than (n = 18) or more than (n = 20) 2.4 x 10(4)/kg CFU-GM. These two groups were comparable for diagnosis, disease status, donor sex, donor age, recipient sex, recipient age, CVHD prophylaxis, number of cells infused and CMV serology. Neutrophil counts were comparable at all time intervals. There was also no difference in platelet counts on days +7 to +50. However, patients who had received higher CFU-GM numbers had significantly higher platelet counts on day +80 (149 vs. 75 x 10(9)/L; P = 0.002), day +100 (153 vs. 77 x 10(9)/L; P = 0.0009) and day +150 (179 vs. 95 x 10(9)/L; P = 0.01). The 2-year actuarial transplant-related mortality was 5% vs. 53% (P = 0.007) in patients receiving high or low numbers of CFU-GM.(ABSTRACT TRUNCATED AT 250 WORDS)