IgM against Coxsackie B viruses in children developing type I diabetes mellitus--a seven-year retrospective study.

IgM antibodies to coxsackievirus type B 1-5 (CB 1-5) have recently been observed in sera from children with newly diagnosed insulin-dependent diabetes mellitus (IDDM). In the present study IDDM patients below 15 years of age diagnosed between 1978 and 1984 inclusive in two different areas (counties) of Sweden, Uppsala and Linköping, were studied at the onset of their disease. The incidence of IDDM per 100,000 children below the age of 15 years varied between 11.1 and 40.8, with a mean of 26.3 in Uppsala and 23.0 in Linköping. CB-IgM was determined by a mu-antibody capture radioimmunoassay (RIA) and was found in the sera of 40% (range 15-76%) of the Uppsala patients and 30% (0-57%) of the Linköping patients. The IDDM onset peaked in January, August and October, and these months also displayed the largest numbers of CB-IgM-positive cases. There seemed to be a relation between IDDM incidence and CB-IgM positivity, but not during the whole period. IgM antibodies against CB2 and CB3 predominated during the first part of the study period, whereas during the last two years IgM antibodies against all five serotypes were demonstrated. It is concluded that if CB virus infection is involved in the pathogenesis of IDDM in children, this may be the case in less than half of the patients, though with seasonal and annual peaks and nadirs and also changes of serotypes that may reflect the natural epidemiology of these viruses.