Latent infection and reactivation of human cytomegalovirus

Abstract

Human cytomegalovirus (HCMV) is the most common cause of congenital and perinatal infections throughout the world. Primary infection with HCMV usually follows a benign course, but the virus remains latent or persistent in the host cell thereafter. Under immunosuppressive conditions, latent or persistent infection can be reactivated to produce a wide variety of clinical manifestations. Understanding the epidemiology of HCMV infection is a key element in development of strategies for prevention of infection. Definition of sites and mechanisms involved in the maintenance of latent or persistent HCMV infection and reactivation is also essential for a thorough understanding of the pathogenesis of HCMV infection. This mini review focuses on recent advances in the study of persistent infection and reactivation of HCMV. Although the actual sites of latency or persistence of HCMV infections are still controversial, peripheral blood mononuclear cells (PBMC) and endothelial cells appear to be the principal site of infection. Persistent infections caused by HCMV could be augmented by a decrease in major histocompatibility complex (MHC) expression as well as by virus-mediated immune dysfunction. It is also likely that specific cellular interactions as well as production of several cytokines are necessary for the reactivation of HCMV.