Interaction of human cytomegalovirus with monocytes/macrophages: a love-hate relationship

This review addresses the complex interactions of human cytomegalovirus (CMV) with the phagocytic mononuclear cell system. Certain aspects may be supplemented with observations made in animal systems. An attempt will be made to summarize information acquired through in vivo studies about the distribution of CMV in the mononuclear phagocyte cells, the state of the virus in such cells and the reactivation of virus in this setting. Much information has been gained through in vitro experimentation attempting to elucidate the infectability of and replication in monocytes/macrophages, and the role played by the cellular differentiation in these events. The influence of CMV infection on the generation of macrophages and granulocytes from bone marrow progenitors will also be examined. The modifications of host cell function induced by CMV infection, notably the production of cytokines and antigen presentation will be examined. The possible significance of CMV infection of monocytes/macrophages relative to viral dissemination, immunosuppression, and hematological modifications associated with CMV infection will be discussed.