Pathogenesis of GVHD: role of herpes viruses

The pathogenesis of GVHD is not fully elucidated. Some groups of patients have a higher risk of developing GVHD post-BMT than others. Environmental factors may be important. Much attention has focused on the role of viruses, particularly herpes viruses, in GVHD. CMV in particular has been implicated as a pathogenic agent. Data from animal work and from observations of the frequent clinical association of CMV with GVHD have suggested a pathogenic link. Several large multi-centre seroepidemiological studies have been performed in an attempt to clarify this issue. This review discusses the data implicating herpes viruses in the pathogenesis of GVHD and considers the mechanisms by which viruses may exacerbate or initiate GVHD. Implications for the management of allogeneic BMT patients are discussed.