HUMAN CYTOMEGALOVIRUS CELL TROPISM AND PATHOGENESIS

The human cytomegalovirus (HCMV) can cause lifelong infection with epi sodes of endogenous reactivation. Intrauterine fetal infection and inf ection of immunocompromised patients are well known to result in signi ficant morbidity. Studies on HCMV cell tropism in vivo revealed three characteristics: (1) ubiquitously distributed cell types such as epith elial cells, endothelial cells and fibroblasts are the major targets o f HCMV infection; (2) leukocytes circulating in the peripheral blood a re susceptible to the virus, and (3) specialized parenchymal cells suc h as smooth muscle cells in the gastrointestinal tract and hepatocytes can also be infected. Questions to be resolved are, how the virus spr eads throughout the organism, how it can impair the function of infect ed organs, and how it evades the host's immune response to establish l ifelong infection. This chapter is focused on the role of HCMV-infecte d target cells for the pathogenesis of HCMV-associated disease in the acutely infected immunocompromised host.