Serum antibodies reactant with Korean haemorrhagic fever agent in Scandinavian epidemic (endemic) nephropathy (nephropathia epidemica) demonstrated by immunofluorescence utilizing an in vitro antigen source.

A newly developed spot slide immunofluorescence method utilizing an in vitro antigen source was used for the first time for the assay of antibodies reactant with the Korean haemorrhagic fever (KHF) agent in sera from patients diagnosed with Scandinavian epidemic (endemic) nephropathy (nephropathia epidemica, NE) and from age-matched control patients living in the same area as the NE patients but suffering from other diseases. KHF antibodies were demonstrated in all of 14 NE patients who were followed prospectively, 7 of whom exhibited seroconversion and in 6 of 8 NE patients studied retrospectively, but in only one of 42 controls. Antibodies in NE appeared within the first week of onset of symptoms and persisted for long periods of time as seen in KHF. The time from the onset of the illness until maximum antibody titre was recorded varied from 9 days to 1 month. On an average, the level of the antibody titres measured in NE was lower than that usually encountered in the Korean disease. The results indicate a close antigenic relationship between the KHF and NE agents and demonstrate that the reliability of our new spot slide method is similar to that of another previously reported and more laborious immunofluorescence method using lung from infected rodents as antigen source.