Detection of specific serum immunoglobulin M in nephropathia epidemica (Scandinavian epidemic nephropathy) by a biotin-avidin-amplified immunofluorescence method.

A biotin-avidin-amplified indirect immunofluorescence method was used to demonstrate specific serum immunoglobulin M (IgM) antibodies in nephropathia epidemica, the Scandinavian type of hemorrhagic fever with renal syndrome. The antigen in the test was the cross-reacting agent of Korean hemorrhagic fever, Hantaan virus. Sixty-two serum samples from 15 patients with clinically typical nephropathia epidemica were analyzed. Eleven patients had specific IgM in one or more serum samples. The IgM could be demonstrated from day 2 up to day 37, and all patients had detectable specific IgM within 15 days after the onset of disease. In 49 control serum samples, no specific IgM could be detected, indicating a high specificity for the method. The findings demonstrate that the biotin-avidin-amplified immunofluorescence IgM assay is a useful tool in the diagnosis of early nephropathia epidemica disease.