Diagnosis of human parvovirus B19 infections by detection of epitope-type-specific VP2 IgG

In the B19 VP2 molecule an immunodominant heptapeptide epitope has been det ected, recently for which IgG antibodies are synthesized exclusively in the acute phase of B19 infection. Using this acute-phase-specific epitope (KYV TGIN) a 2(nd)-generation epitope-type EIA was developed, wh ich compares se rum IgG activity for native VP2 capsids exhibiting conformational VP2 epito pes with IgG activity for the KYVTGIN epitope. In this study the diagnostic performance (clinical sensitivity and specificity) of the 1(st) and 2(nd)- generation epitope-type EIAs and of a peptide-based EIA utilising as antige n the KYVTGIN epitope alone was assessed in comparison with various high-qu ality IgM- and IgG- based B19 assays. Serum samples from 489 patients with B19-related symptoms and asymptomatic controls from three countries were st udied. Among 323 patients with B19-IgG, 20% were diagnosed as acute infecti on, 73% had past immunity and 7% were not classified due to contradictory r esults among the different assays. The unclassified samples were explored f or viral strain diversity by PCR and DNA sequencing but all sequences obtai ned were B19-like with variance of only a few per cent. The 2(nd)-generatio n epitope-type EIA had a diagnostic sensitivity of 98% and diagnostic speci ficity of 94%. In combination with conventional approaches, the epitope-typ e assays increase greatly the accuracy of B19 serodiagnosis. (C) 2001 Wiley -Liss, Inc.