Pathogenesis of human parvovirus B19 in rheumatic disease

Human parvovirus B19, discovered in 1975(1) and first. linked with human di sease in 1981,(2) is a small single stranded DNA virus classified within th e family Parvoviridae, and the genus Erythyrovirus, having tropism primaril y for erythroid precursors. B19 is the only parvovirus which has been clear ly linked with disease in humans. It replicates only in human cells and is autonomous, not requiring the presence of a helper virus. Acute B19 virus infection is classically associated with the childhood rash illness, erythema infectiosum (EI), arthralgia, fetal death, and transient aplastic crisis (TAC) in those with shortened red cell survival. However, it has been assumed that in those with a normal immune system, the virus ha s a relatively simple pathogenesis and that after the acute phase the virus is cleared by a specific humoral immune response. However, increasingly B1 9 virus and B19 infection have been reported in association with quite atyp ical and unpredictable findings based on previous assumptions. For example, persistence of the virus in various tissues after acute infection in appar ently normal subjects and the association of B19 infection with various con nective tissue and autoimmune diseases. This paper will therefore summarise present knowledge of the virus, its known and potential pathogenetic mecha nisms, and its associations with human disease, with an emphasis on rheumat ic disease.