We investigated the association between serum antibodies to cow's milk proteins and insulin-dependent diabetes mellitus (IDDM) in Hungarian children. Forty-eight children 1.0-17.1 years of age with newly diagnosed IDDM and 74 control children 1.0-16.0 years of age were studied for serum IgG, IgA and IgM antibodies to cow's milk, beta-lactoglobulin, bovine serum albumin and ovalbumin by enzyme-linked immunosorbent assays. The specificity of IgM antibodies to beta-lactoglobulin and bovine serum albumin was controlled by Western blot. The levels of IgG and IgA antibodies to cow's milk proteins were similar in children with and without IDDM, with the exception of slightly increased levels of IgA antibodies to beta-lactoglobulin in diabetic children (P = 0.05). The levels of IgM antibodies to cow's milk were significantly higher in IDDM patients than in control children (P = 0.0002). Children with IDDM more often had IgM antibodies to beta-lactoglobulin (46.3% vs 18.8%; P = 0.002) and bovine serum albumin (87.8% vs 49.3%, P < 0.0001) than control children. Neither the levels of IgG or IgA antibodies to ovalbumin nor the frequency of IgM antibodies to ovalbumin differed between diabetic and control children.
Conclusion: In Hungarian children, clinical manifestation of IDDM is often associated with IgM antibody response to cow's milk protein and its fractions, beta-lactoglobulin and bovine serum albumin, indicating a loss of immunological tolerance to these proteins. IgG and IgA antibodies to cow's milk proteins, associated with an early introduction of cow's milk in diet, seem to play a minor role in the development of childhood IDDM in Hungary.