CELLULAR IMMUNE-RESPONSES TO BETA-CASEIN - ELEVATED IN BUT NOT SPECIFIC FOR INDIVIDUALS WITH TYPE-I DIABETES-MELLITUS

Elevated cellular immune responses against the cows' milk protein beta casein have been reported in individuals with Type I diabetes mellitu s, a finding supportive of the concept that cows' milk consumption may be causative for the disease. We analysed cellular immune reactivitie s against beta casein in newly-diagnosed Type I diabetic patients, the ir immediate autoantibody negative relatives, and unrelated healthy in dividuals in order to further elucidate the role of anti-beta casein i mmunity in the pathogenesis of Type I diabetes mellitus, Peripheral bl ood mononuclear cells were stimulated in vitro with various concentrat ions of three different beta casein preparations, control antigens (te tanus toroid, mumps extract) and a mitogen (phytohemagglutinin). The f requency and/or mean simulation index of cellular proliferation agains t two of the beta casein preparations at high antigen concentrations ( i.e. 10 or 50 mu g/ml) were significantly higher in newly-diagnosed Ty pe I diabetic subjects compared with autoantibody negative healthy con trol subjects. However, reactivities against beta casein in the Type I diabetic probands and their autoantibody negative relatives, individu als with a very low-rate of disease development, were almost identical . Cellular immune reactivities to other antigens were similar between the subject groups. In addition to indicating the need for appropriate ly matched subject populations (e.g. human leukocyte antigen (HLA) mat ched relatives) when analysing cellular immune responses, these findin gs support our previous contention that individuals genetically prone to autoimmunity may be deficient in forming tolerance to dietary antig ens. However, the significance of anti-beta casein immunity as a speci fic causative factor in the pathogenesis of Type I diabetes mellitus r emains unclear.