Immune Reconstitution After Double Umbilical Cord Blood Stem Cell Transplantation: Comparison With Peripheral Blood Stem Cell Transplantation

Molecular diagnosis and management of viral infections in hematopoietic stem cell transplant recipients

Viral infections after allogeneic hematopoietic stem cell transplantation (HSCT) are important complications associated with high morbidity and mortality. In this setting, reactivations of persisting latent viral pathogens from donor and/or recipient cells play a central role whereas the sterile environment of transplant units renders new infections less likely. The viruses currently regarded as most relevant in the HSCT setting include particularly the herpes virus family--specifically cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6)--as well as human adenoviruses (AdVs) and the polyoma virus BK (BKV). Timely detection and monitoring of virus copy numbers are prerequisites for successful preemptive treatment approaches. Pre- and post-transplant surveillance by sensitive and quantitative molecular methods has therefore become an essential part of the diagnostic routine. In this review, we discuss diagnostic aspects and the clinical management of the most important viral infections in HSCT recipients, with a focus on pediatric patients.

Reduced-intensity conditioning stem cell transplantation: comparison of double umbilical cord blood and unrelated donor grafts

There are little data comparing umbilical cord blood (UBC) and conventional stem cell sources for reduced-intensity conditioning (RIC) hematopoietic stem cell transplantation (HSCT). We performed a retrospective analysis of RIC HCST using double UCB (dUCB) grafts and RIC HSCT using unrelated donor (URD) grafts. The study included 64 dUCB transplantations and 221 URD transplantations performed at Dana-Farber Cancer Institute and Massachusetts General Hospital between 2004 and 2008. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 14.1% for dUCB and 20.3% for URD (P = .32). The 2-year cumulative incidence of chronic GVHD was significantly lower in dUCB compared with URD (21.9% versus 53.9%; P < .0001). The 2-year cumulative incidence of nonrelapse mortality was significantly higher in dUCB (26.9% versus 10.4%; P = .0009). In our analysis, dUCB HSCT and URD HSCT had comparable 3-year overall survival (46% in dUCB and 50% in URD; P = .49) and progression-free survival (30% in dUCB and 40% in URD; P = .47). dUCBT was associated with greater nonrelapse mortality despite less chronic GVHD. Our findings suggest that the use of 2 partially matched UCB units appears to be a suitable alternative for patients undergoing RIC HSCT without an HLA-matched donor.