Increased levels of cow's milk and beta-lactoglobulin antibodies in young children with newly diagnosed IDDM. The Childhood Diabetes in Finland Study Group.

OBJECTIVE: To investigate the humoral immune response to cow's milk in pediatric patients with newly diagnosed IDDM. RESEARCH DESIGN AND METHODS: We measured IgA, IgG, and IgM antibodies to the proteins of cow's milk and to beta-lactoglobulin by an enzyme-linked immunosorbent assay. Samples from 706 pediatric patients with newly diagnosed IDDM were available. We used two comparison groups: 105 patients < 7 yr old had an unrelated age-matched control subject, and samples from 456 3- to 14-yr-old nondiabetic siblings also were available.
RESULTS: Patients < 3 yr of age had a markedly higher median level of IgG and IgA antibodies to cow's milk compared with the control subjects (P = 0.03 and 0.002, respectively), IgG antibodies to beta-lactoglobulin also were higher (P = 0.03). Older groups of diabetic patients, 3.0-6.9 and 7.0-14.9 yr of age, had significantly higher levels of IgA antibodies to cow's milk and beta-lactoglobulin than the age-matched comparison groups of both unrelated control subjects and nondiabetic siblings, although the median values of the diabetic patients were closer to those of the comparison groups than in the youngest groups. Nondiabetic siblings had higher levels of IgA cow's milk antibodies than unrelated control subjects of similar ages (3-6.9 yr of age) (P = 0.03). The 14 siblings contracting IDDM during the follow-up showed no change in the levels of cow's milk or beta-lactoglobulin antibodies in relation to the clinical diagnosis.
CONCLUSIONS: The results indicate an abnormally strong humoral response to the proteins of cow's milk, particularly in young IDDM patients and, to a lesser extent, in their siblings. We infer that the proteins of cow's milk may trigger the autoimmune process of IDDM.