Cellular and Humoral Immunity against Cow's Milk Proteins in Type 1 Diabetes

Cow's milk β-casein has been proposed as a candidate trigger of autoimmunity associated with type 1 diabetes. In this study, cellular and humoral immunity against β-casein was compared to that against other major cow's milk proteins in patients with recent onset type 1 diabetes and control subjects. T cell responses were found against α-casein, β-casein, β-lactoglobulin and bovine serum albumin in both patients with type 1 diabetes (stimulation index: 0.2–22.8, n=23) and control subjects (stimulation index: 0.1–18.2, n=22), with no significant differences between groups. Twelve (52%) patients and nine (41%) control subjects had stimulation indices >3 to at least one protein, including 9 (39%) patients and 4 (18%) control subjects against β-casein, all but one of these also having elevated responses to α-casein. The highest responses (stimulation index >9) were against α- and β-casein in some patients and control subjects who had the HLA DR3 allele. Antibody levels against α-casein, β-casein and β-lactoglobulin were low in both patients (n=59) and control subjects (n=52). Nevertheless, significantly higher IgG binding to both α-casein in ELISA (P=0.02) and β-casein using ELISA (P=0.02) and RIA (P=0.04) was observed in patients aged