Influence of CD34 + marrow cell dose on outcome of HLA-identical sibling allogeneic bone marrow transplants in patients with chronic myeloid leukaemia

In order to study the influence of bone marrow CD34 + cell dose on the outcome of allogeneic bone marrow transplantation (BMT), we analysed the results of BMT from HLA-identical siblings donors in 50 patients with chronic myeloid leukaemia (CML). The median numbers of nucleated cells (NC) and CD34 + cells infused were 2.18 × 10 8 /kg (0.05–4.14 × 10 8 /kg) and 3.12 × 10 6 /kg (0.35–8.52 × 10 6 /kg), respectively. All patients engrafted. In univariate analysis, there was no correlation between the number of CD34 + cells infused and the time to neutrophil recovery ( P = 0.17). The Kaplan–Meier estimate of grade II–IV acute graft-versus-host disease (GVHD) at day 100 was 53 ± 14% and 2-year survival was 46 ± 15%. A number of CD34 + cells infused greater than the median was the main factor increasing survival ( P = 0.0006) and decreasing 100 day transplant-related mortality ( P = 0.009). Patient-, disease- and transplant-related characteristics were not statistically different among patients receiving more or less than the median number of CD34 + cells. The rate of infectious deaths was significantly higher in patients receiving less than 3.12 × 10 6 CD34/kg (48% vs 16%, P = 0.01). In a multivariable analysis, two factors associated with increased risk of death were advanced disease status at transplant (HR: 2.5 (95% CI: 1.09–5.75), P = 0.03) and a lower number of marrow CD34 + cells infused/kg (HR: 4.55 (95% CI: 1.87–10.90), P = 0.0008). Bone Marrow Transplantation (2001) 27, 575–580.