IgE-based assay for early detection of HIV-1 infection in infants

Abstract

5Serum samples were collected from patients with HFRS in the Tula region during the outbreak and from convalescent patients (collected between 1 month and 4 years after disease) in the Tula and Ryazan regions. Initial serological screening by immunofluorescence assay (IFA) revealed higher antibody titres to Hantaan, Seoul, 5 and DOB (N Apekina, unpublished) antigens than to Puumala. These findings indicated that a hantavirus other than Puumala virus was the causative agent of the outbreak. In our study of 22 hantavirus-IgG-positive serum samples, as confirmed by ELISA with Puumala, DOB, and Hantaan antigens, 2 all showed the highest reactivities to DOB. However, since previous studies have identified high levels of crossreactive antibodies to several hantaviruses by IFA or ELISA analysis, the serum samples were further assayed by focus-reduction neutralisation test which allows precise serotyping. To avoid misleading crossreactivity of neutralising antibodies during the acute phase of HFRS, 2 only samples from convalescent patients obtained more than 1 month after onset of disease, were selected. Nine such samples were analysed against the hantaviruses known to cause HFRS and the putatively apathogenic Tula virus (table). All serum samples showed high specificities of neutralising antibodies to DOB, confirming its involvement in the Tula-Ryazan outbreak. Our results do not confirm the previously proposed involvement of Seoul virus in the outbreak because none of the serum samples showed significant titres to this hantavirus.