Abstract
Gastrointestinal symptoms such as vomiting, bloody stool or diarrhea sometimes develop in bottle-fed neonates or younger infants. Althouth IgE antibody for cow's milk is usually negative in these patients, we demonstrated that allergen-specific lymphocyte stimulation test (ALST) for cow's milk protein was positive in most cases, suggesting that the cell-mediated hypersensitivity against cow's milk plays a critical role in the pathogenesis. Thus, we provisionally named the disease early infantile intestinal cow's milk allergy (ICMA). Although κ-casein and α-lactalbumin is regared as less allergenic than αs-casein or β-lactoglobulin in IgE-mediated cow's milk allergy, they showed a potent capacity to activate lymphocytes in ICMA patients. In contrast to IgE-mediated cow's milk allergy, these proteins seem to make a significant contribution to the development of ICMA as major allergens. ICMA develops not only in bottle-fed but also in breast-fed infants. To explore the cause of this problem, we measured ALST for human α-lactalbumin because it is a major component of breast milk and highly homologous to cow's milk α-lactalbumin. Although ALST for human α-lactalbumin was low in most ICMA patients, some showed increased ALST levels comparable to that for cow's milk counterpart. Thus, cross-reactions of lymphocytes to human α-lactalbumin appears to be related to the development of ICMA in breast-fed infants.
