Infections After High-Dose Chemotherapy and Autologous Hematopoietic Stem Cell Transplantation

Infection represents an important cause of morbidity after autologous hematopoietic stem cell transplantation (HSCT). Immunodeficiency is the key risk factor and results from interplay between the underlying disease and its therapy. Various defects in the immune system coexist in HSCT recipients. In the early post-transplant period, neutropenia, oral and gastrointestinal mucositis, and the presence of central venous catheters are the main risk factors. Bacterial infections predominate, and the agents and antibiotic susceptibility profiles vary widely in different regions. Invasive candidiasis is infrequent with fluconazole use, but the incidence of invasive aspergillosis is on the rise, mainly in patients receiving purine analogues or intensive chemotherapy before transplant. In the post-engraftment period, infections are less frequent, but may contribute to significant non-relapse mortality. The dynamics of immune reconstitution drives the risk for infection in this period. The most frequent infections are varicella-zoster virus disease and respiratory tract infections. Assessment of the risk of infection in each period and the identification of patients at higher risk of specific infections are critical to the appropriate management of infectious complications after autologous hematopoietic stem cell transplantation.