HUMORAL IMMUNITY AGAINST VIRAL ANTIGENS IN TYPE 1 DIABETES: ALTERED IgA‐CLASS IMMUNE RESPONSE AGAINST COXSACKIE B4 VIRUS

A group of 210 pediatric Type 1 diabetic patients with long duration of illness and their matched controls (age range 2-19 years) were analysed for Coxsackie B4 antibodies in IgG-, IgM- and IgA-antibody classes by enzyme-linked immunosorbent assay (ELISA). About 60% of both patients and controls were seropositive. However, patients had higher prevalence and mean levels of IgA-class antibodies compared to controls. No such difference was found in IgG- or IgM-antibody classes. The elevation of IgA-class antibody levels was evident early after the Coxsackie B4 infection and seemed to persist for several years. IgA-class antibody levels did not differ between sexes in either patients or controls. The elevated levels of IgA-antibodies against Coxsackie B4 virus did not correlate with the elevated IgA antibodies against mumps virus, which served as control antigens. Thus it seems that in IDDM patients the abnormal IgA response against both Coxsackie B4 and mumps virus is antigen-specific.