Effect of busulfan on neutrophil and platelet counts. (A) The absolute neutrophil count for each patient is plotted beginning before transplant (baseline) to day 50 after transplantation. Cell infusion was day 0 and the busulfan was given days −3 and −2. (B) The platelet count for each patient is plotted beginning before the busulfan and until all patients no longer required any transfusions, day 48.