[Sensitization to casein and beta-lactoglobulin (BLG) in children with cow's milk allergy (CMA)]

The objective of this study was to analyze the sensitization to casein and beta-lactoglobulin (BLG) in children with cow's milk allergy (CMA) in Japan. To this end, 115 CMA children were selected on the basis of the presence of cow's milk-specific IgE antibodies in serum and compatible clinical history. Specific IgE antibodies against casein and BLG were determined using CAP-RAST (considered positive when score 2 or more).

Titer of anti-casein IgE was significantly higher than that of anti-BLG IgE in CMA patients. IgE antibodies specific to casein were positive in 107 patients (97.3%), while those to BLG were positive in 51 patients (46.6%). Forty-eight patients (43.6%) were positive to both casein and BLG. We divided patients to two groups who were sensitized to casein only (C group) and who were sensitized to both casein and BLG (C/B group). No significant difference was seen in sensitization rate to white egg between C/B group and C group. However titer of anti-white egg IgE was significantly higher in C/B group than C group. As for sensitization rate and levels of specific antibodies to mite and Japanese cedar pollen there was no difference between two groups. Rates of resolution of CMA at the 3 years of age were higher in the C group than C/B group.

In conclusion we found that casein is a major allergen of cow's milk allergy in Japanese children. Patients who are sensitized to several milk allergens are likely to be more sensitized to other food allergens. Sensitization to several milk allergens tends to have poor prognosis of CMA.