Specific humoral reaction of hemorrhagic fever with renal syndrome (HFRS) patients in China to recombinant nucleocapsid proteins from European hantaviruses.

Hemorrhagic fever with renal syndrome (HFRS) is endemic in East Asia and Europe. This study was initiated to investigate the reactivity of antibodies in sera of Chinese HFRS patients with the recombinant nucleocapsid proteins (rNPs) of Hantaan virus (HTNV), Dobrava-Belgrade virus (DOBV), and Puumala virus (PUUV), which are the prevalent hantavirus strains in Europe. Forty-eight pairs of acute and convalescent sera were collected from HFRS patients in Hubei, China (1985-2002) and tested by indirect IgG, IgA, and IgM enzyme-linked immunosorbent assays with six rNPs of European hantaviruses as coated antigens, respectively. The results showed that the sensitivity of rNPs against IgG was HTNV-rNP > DOBV-rNP > PUUV-rNP, while the sensitivity against IgA was DOBV-rNP > HTNV-rNP > PUUV-rNP. Quantitative analysis revealed both acute and convalescent sera from HFRS patients predominantly exhibit high levels of IgA. Although PUUV-rNPs showed very weak reactivity to the three kinds of immunoglobulins in all samples, three pairs of sera unexpectedly cross-reacted strongly to all three PUUV-rNP subtypes. We first observe that HFRS patients' sera from Hubei Province show new prevalent characteristics of cross-reacting with PUUV-rNPs and continued high level of IgA in convalescent phase, as well as in China.