Cellular and humoral immunity against cow's milk proteins in type 1 diabetes

Duration of breast feeding and bovine serum albumin antibody levels in type 1 diabetes: a case-control study

OBJECTIVE

To compare the levels of bovine serum albumin (BSA) antibodies and their relationship with duration of breast feeding, age of exposure to cow's milk, and human leukocyte antigen (HLA-DQ) genotype in children with and without type 1 diabetes.

METHODS

Serum samples from 143 (0.3-14.7 yr) newly diagnosed children with type 1 diabetes and 107 unrelated control children (0.8-13.5 yr) were evaluated for BSA antibodies. Duration of breast feeding and exposure to cow's milk were recorded on questionnaires. HLA-DQ typing was determined by polymerase chain reaction.

RESULTS

One hundred percent of the diabetic children were positive for BSA antibodies compared to 1.9% for healthy controls (p < 0.001). Diabetic children also had higher levels of immunoglobulin G antibodies than unrelated controls (55.1 vs. 17.8 ng/mL, p < 0.0001). Duration of breast feeding (5.4 vs. 7.6 months, p < 0.02), but not age of exposure to cow's milk (8.3 vs. 9.2 months, p = 0.11), differed between cases and controls. There was no difference in antibody titer by duration of breast feeding or age of exposure to cow's milk in the cases or controls.

CONCLUSION

Higher levels of antibodies to BSA were found in children recently diagnosed with type 1 diabetes compared to the controls, particularly those with high or moderate HLA-DQ genotypes. The BSA profile, however, does not seem to depend on duration of breast feeding or age of exposure to cow's milk in this population.

Identification of caseins in goat milk

The importance of goat milk in infant diet is growing, because it is reported that goat's milk in some cases is less allergenic than cow's milk. This is due probably to the lower presence of caseins associated with a specific type of alpha(s1)-casein. In caprine breeds, four types of alpha(s1)-casein alleles are identified and associated with various amounts of this protein in milk. The contribution of strong alleles to the goat milk is approximately 3.6 g/L of alpha(s1)-casein, while for middle alleles is only 1.6 g/L, weak alleles 0.6 g/L. The contribution of null allele is very low (or non-existent). The quantity of total caseins in caprine milk is positively correlated with the amount of alpha(s1)-casein. Milk from animals possessing strong alleles contain significantly more total caseins than milk from animals without those alleles. This is important because animals with mild alleles can be employed to produce milk for allergic subjects while the other animals can be used to produce milk for the dairy industry. This work shows casein profiles of two types of classified goat milk (B, strong alpha(s1) allele, 0, null alpha(s1) allele) with two-dimensional electrophoresis coupled with matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and it confirms the different polymorphisms at locus alpha(s1) casein.

Bovine beta-casein antibodies in breast- and bottle-fed infants: their relevance in Type 1 diabetes

BACKGROUND

Bovine beta-casein is a cow's milk protein that targets both humoral and cellular immune responses in patients with Type 1 diabetes and, to a lesser degree, also in normal subjects. In this study we aimed to determine whether the avoidance of cow's milk consumption early in life could prevent the development of antibody response to bovine beta-casein despite the mother being exposed on a daily basis to cow's milk consumption.

MATERIALS AND METHODS

We measured the antibody response to bovine beta-casein using an ELISA method in 28 healthy infants under 4 months of age, of whom 16 were exclusively breast-fed and 12 were bottle-fed with cow's milk. In addition, beta-casein antibodies were measured in 37 prepubertal children with Type 1 diabetes and in 31 healthy children who were exposed to cow's milk or dairy products to see whether differences in antibody titers exist in this young age group. Antibodies binding to beta-casein were also evaluated by immunoblotting analysis.

RESULTS

Elevated levels of beta-casein antibodies were found in bottle-fed infants compared to breast-fed infants (p<0.0001). Antibody levels to bovine beta-casein were also significantly higher in children with Type 1 diabetes compared to age-matched controls (p=0.03). By western blot analysis we confirmed specific binding to bovine beta-casein in bottle-fed infants, in children with Type 1 diabetes and in controls exposed to cow's milk, but not in infants who were exclusively breast-fed.

CONCLUSIONS

The results of this study indicate that breastfeeding within the first 4 months of life prevents the generation of antibody response to bovine beta-casein despite the mothers' consumption of cow's milk during the breastfeeding period. These findings may have relevance for disease prevention.