Prevalence of antibodies to human parvovirus B19 nonstructural protein in persons with various clinical outcomes following B19 infection

Persistent infections with human parvovirus B19 (B19) associated with debil itating chronic disease have been described, although evidence linking B19 to these more unusual clinical outcomes has been inconclusive. Recent repor ts have suggested that the development of antibodies to the B19 nonstructur al protein (NS1) following B19 infection might be linked to development of severe arthropathy and chronic infection. To confirm these findings, the C- terminal region of the NS1 protein was expressed for use in Western blot as says for detection of anti-NS1 IgG antibodies in human serum. Among 91 pers ons tested, 0 of 20 not previously infected with B19, 9 (36%) of 25 with pa st B19 infection, and 5 (12.5%) of 40 with recent B19 infection, had detect able anti-NS1 antibodies. Of 6 persons with chronic B19 infection, 2 had de tectable antibodies to NS1. The presence of anti-NS1 antibodies did not app ear to correlate with unusual clinical outcomes or chronic B19 infection.