Prevalence of cryoglobulinemia in chronic hepatitis C virus infection and response to treatment with interferon-alpha

A recombinant Schistosoma mansoni protein has been identified as a useful antigen for the detection of S. mansoni and Schistosoma haematobium antibodies. The purified recombinant protein, Sm22.3, was assayed using an enzyme-linked immunosorbent assay format against a battery of 491 well defined sera, including S. mansoni, S. haematobium, and Schistosoma japonicum infection sera, normal human sera, sera from 9 other parasitic infections, and sera from 2 additional infections. The sensitivity for detecting S. mansoni and S. haematobium infections with this single recombinant protein is 80.1%. The specificity is 94.8%. However, 15 of the 16 cross-reactive sera are malaria infection sera, and we have data suggesting that these malaria sera are actually recognizing an epitope on the vector-derived 6Xhistidine tag of recombinant Sm22.3. If this is the case, then, the actual specificity of the assay is 99.6%.