Cytomegalovirus Infection After Hematopoietic Stem Cell Transplantation in Children

Infectious complications remain one of the main problems contributing to significant morbidity and mortality after hematopoietic allogeneic stem cell transplantation (HSCT), and Human cytomegalovirus (HCMV) infection is one of the most frequent and well-known among them. In the last two decades, progress has been made in the diagnosis and monitoring of HCMV infection in HSCT recipients, thanks to the introduction of quantitation of pp65 in peripheral blood leukocytes (antigenemia) and quantitation of viral genome in the blood (DNAemia). This has allowed treatment to be administered during the pre-symptomatic phase of HCMV infection (pre-emptive therapy) and has greatly reduced HCMV-related morbidity and mortality. The advantages of the pre-emptive treatment approach include (i) treating a lower number of patients for shorter periods of time and (ii) avoiding the reported emergence of HCMV disease after discontinuing anti-HCMV prophylaxis. Our aims are to describe the pathogenesis of HCMV reactivation and disease and to analyze the risk factors and mechanisms of the immune response as well as the clinical history of HCMV-disease and the HCMV management in HSCT patients, through an overview of the recent literature.