Circulating immune complexes, immunoconglutinins, and rheumatoid factors in nephropathia epidemica

Circulating immune complexes (CICs), immunoconglutinins, and antiglobulins were studied in nephropathia epidemica, an acute infectious hemorrhagic fever occurring in Finland and Scandinavia. Sixty-one serum specimens from 18 serologically confirmed patients were collected between day -5 and day 230 from the onset of fever. Five CIC tests, three immunoconglutinin tests, and various other tests were used to characterize the disease immunologically. CICs were found in all patients. The percentage detection of positive cases varied in the tests from 100% to 22%. A marked stimulation of levels of the IgM class of immunoglobulins were observed. Antiglobulin tests were positive for all of the patients. No correlation between the test results and the clinical severity of the disease could be found. Of special interest was the delay in the rise of CIC levels compared with the chromologic pattern of the clinical course. In some patients a prolonged appearance of CICs for eight months was observed.