Cytomegalovirus: the role of CMV post-haematopoietic stem cell transplantation.

Human cytomegalovirus (HCMV) is a large DNA virus that is well equipped to evade host immune responses and able to establish lifelong latency. It is able to modulate both innate and adaptive immune reactivity, and has multiple effects on the cell cycle and apoptosis. It is a major opportunistic pathogen in immunocompromised hosts. Reactivation of latent virus may re-stimulate memory T-cell responses that are sufficient to re-establish control over viral replication if the degree of immune suppression is not too great. Following allogeneic transplantation immune responses are often inadequate resulting in progressive tissue damage manifesting as over HCMV disease that usually presents as pneumonitis, colitis or hepatitis. Currently available antiviral pharmacotherapies are limited by toxicities and lack of efficacy in established HCMV disease. Efforts have therefore focused on molecular diagnostic surveillance protocols that allow earlier intervention, and the development of adoptive immunotherapeutic strategies to hasten host immune reconstruction.