Association of CD34 cell dose with hematopoietic recovery, infections, and other outcomes after HLA-identical sibling bone marrow transplantation.

Although CD34 cell dose is known to influence outcome of peripheral stem cell- and/or T-cell-depleted transplantation, such data on unmanipulated marrow transplantation are scarce. To study the influence of CD34(+) cell dose on hematopoietic reconstitution and incidence of infections after bone marrow transplantation, we retrospectively analyzed 212 patients from January 1994 to August 1999 who received a transplant of an unmanipulated graft from an HLA-identical sibling donor. Median age was 31 years; 176 patients had hematologic malignancies. Acute graft-versus-host disease prophylaxis consisted mainly in cyclosporin associated with methotrexate (n = 174). Median number of bone marrow nucleated cells and CD34(+) cells infused were 2.4 x 10(8)/kg and 3.7 x 10(6)/kg, respectively. A CD34(+) cell dose of 3 x 10(6)/kg or more significantly influenced neutrophil (hazard ratio [HR] = 1.37, P =.04), monocyte (HR = 1.47, P =.02), lymphocyte (HR = 1.70, P =.003), erythrocyte (HR = 1.77, P =.0002), and platelet (HR = 1.98, P =.00008) recoveries. CD34(+) cell dose also influenced the incidence of secondary neutropenia (HR = 0.60, P =.05). Bacterial and viral infections were not influenced by CD34 cell dose, whereas it influenced the incidence of fungal infections (HR = 0.41, P =.008). Estimated 180-day transplantation-related mortality (TRM) and 5-year survival were 25% and 56%, respectively, and both were highly affected by CD34(+) cell dose (HR = 0.55, P =.006 and HR = 0.54, P =.03, respectively). Five-year survival and 180-day TRM were, respectively, 64% and 19% for patients receiving a CD34(+) cell dose of 3 x 10(6)/kg or more and 40% and 37% for the remainders. In conclusion a CD34(+) cell dose of 3 x 10(6)/kg or more improved all hematopoietic recoveries, decreased the incidence of fungal infections and TRM, and improved overall survival.