Infections after CD34-selected or unmanipulated autologous hematopoietic stem cell transplantation

Immune reconstitution may be delayed after CD34-selected compared with unmanipulated autologous peripheral blood stem cell transplantation (PBSCT), resulting in a theoretically increased risk of infections. In a case-control matched study we compared the incidence of infection in 25 recipients of CD34-selected PBSC (CD34 group) and 75 recipients of unmanipulated PBSC (PBSC group) transplants. The population included 52 males and 48 females suffering from non-Hodgkin's lymphoma (n = 32), Hodgkin's disease (n = 8), multiple myeloma (n = 40) or breast cancer (n = 20). Neutrophil engraftment was comparable in the two groups. The actuarial incidence of infection was similar in the two groups (56% vs. 49% at day 30, and 70% vs. 64% at 1 yr respectively). The proportion of patients with 1, 2 or 3 infections, the number of infectious event per patient (1.32 vs. 1.04; NS), the number of infections before day 15 or 30, between days 31 and 100 or after day 100, the risk of varicella-zoster virus or cytomegalovirus infection or disease, or the use of antibiotic or antifungal therapy, were not increased in the CD34 compared with the PBSC group. The main agents responsible for infection were bacteria, particularly gram-positive, cocci, in both groups. Bacteremia accounted for 33% of all infectious events in the CD34 group vs. 16% in the PBSC group (P < 0.05). Fungal infections were rare. In conclusion, our results do not support the notion that CD34-selection of the graft is associated with an increased rate of infection after autologous PBSC transplantation. The role of extended infection prophylaxis should be evaluated.