Higher infused CD34 + cell dose and overall survival in patients undergoing in vivo T-cell depleted, but not t-cell repleted, allogeneic peripheral blood hematopoietic cell transplantation

BACKGROUND AND OBJECTIVESUnderstanding the effect of cellular graft composition on allogeneic hematopoietic cell transplantation (AHCT) outcomes is an area of great interest. The objective of the study was to analyze the correlation between transplant-related outcomes and administered CD34 +, CD3 +, CD4 + and CD8 + cell doses in patients who had undergone peripheral blood, AHCT and received either in vivo T-cell depleted or T-cell replete allografts.DESIGN AND SETTINGComparison of consecutive patients who underwent peripheral blood AHCT in our institution between January 2003 and December 2009.PATIENTS AND METHODSThe cohort of 149 patients was divided into two groups; non T-cell depleted (NTCD) (n = 54) and T-cell depleted (TCD) (n = 95). Study endpoints were overall survival (OS), progression free survival (PFS), engraftment kinetics (neutrophil and platelet recovery), incidence of acute graft versus host disease (acute GVHD), chronic GVHD, non relapse mortality (NRM) and disease relapse.RESULTSMultivariate analysis showed that higher infused CD34 + cell dose improved OS (relative risk 0.58, 95% CI 0.34-0.98, P = .04), PFS (relative risk 0.59, 95% CI 0.35-1.00, P = .05) and NRM (relative risk 0.49, 95% CI 0.24-0.99, P = .048) in the TCD group. By multivariate analysis, there was no difference in engraftment, grades II-IV acute GVHD, extensive chronic GVHD and relapse in the two groups relative to the infused cell doses. There was a trend towards improved OS (relative risk 0.54, 95% CI 0.29-1.01, P = .05) with higher CD3 + cell dose in the TCD group.CONCLUSIONOur findings suggest that higher CD34 + cell dose imparts survival benefit only to in vivo TCD peripheral blood AHCT recipients.