Parvovirus B19: recent insights and implications for pathogenesis, diagnosis and therapy

Parvovirus B19 is a human pathogenic virus, a ssDNA member of the family Parvoviridae, characterized by a selective tropism for erythroid progenitor cells (EPCs) in the bone marrow and an ample pathogenetic potential. The selective tropism for EPCs can be explained both in terms of receptor-mediated tropism and of an intracellular permissive environment conditioned by the cell differentiation and proliferation stage. Infection of EPCs is productive, induces apoptosis and leads to a temporary arrest of erythropoiesis, which can usually be manifest in cases of underlying erythropoietic disorders or immune system deficiencies. Endothelial cells constitute an additional diffuse target, whose infection is mediated by ADE phenomenon, but is normally nonproductive and mainly leading to inflammatory processes. The relevance of parvovirus as a cardiotropic virus is recently emerging, while its capability of intrauterine transmission and consequences on the fetus is known and should not be overlooked. To the purpose of diagnosis, a combination of molecular and immunological methods offers the best discrimination of active infectious processes, and an application of these methods especially in cases of atypical presentations should be encouraged. Ongoing research is directed towards the development of a vaccine and the discovery of antiviral drugs that may be useful in the prevention and treatment of parvovirus B19 infections.