Seroprevalence of parvovirus B19 NS1-specific IgG in B19-infected and uninfected individuals and in infected pregnant women.

Parvovirus B19 is the causative agent of erythema infectiosum in children, but the virus is associated with an increasing range of different diseases. These include acute and chronic arthritis, hydrops fetalis in pregnant women, aplastic anemia, and thrombocytopenia. The host's immune response is directed against the viral structural proteins VP1 and VP2. This study investigated the presence of IgG against the viral nonstructural protein NS1 using Western blot. Serum panels from healthy individuals, B19-infected pregnant women, and various disease groups were tested. The disease groups included patients with symptoms that may be linked to parvovirus B19 infection. The results showed that IgG against the NS1 protein was present in 22% of healthy individuals with past B19 infection. In cases of persistent or prolonged B19 infections, the prevalence of NS1-specific antibodies was as high as 80%. It is concluded that NS1-specific IgG may be used as an indicator of chronic or more severe courses of parvovirus B19 infections.