f76 nBos d 4 α-lactalbumin, Milk

Allergens within Food of Animal Origin

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  • Latin name: Bos spp.
  • Source material: Purified bovine α-lactalbumin
α-lactalbumin is one of the major allergens in cow's milk.

Allergen Exposure

Milk and dairy products.
 
Unexpected exposure
Food containing undeclared milk products.
 
May occur in "milk-free" products as undegraded milk proteins or as contamination from previous productions of food containing milk.

Potential Cross-Reactivity

Milk from related animals.
Presence of common allergens in milk, meat and dander from cow has been demonstrated.

Clinical Experience

IgE-mediated reactions
In studies on milk-allergic patients IgE-antibodies to α-lactalbumin have been identified in approx. 50%, or more, of the patients.
 
Review
α-lactalbumin is regarded as one of the major cow’s milk allergens. Hoffman et al. (1) found 12/25 eczema patients (48%) had IgE antibodies to α-lactalbumin. Another study of 25 milk-allergic patients with a variety of allergic symptoms showed a-lactalbumin-specific IgE antibodies in 67% of the sera (2). A daily dose of less than 70 mg a-lactalbumin by intake of a "milk-free" cereal flour containing lactose caused repeated episodes of vomiting and diarrhea in a 22 months old child. Food products containing lactose of "food quality" may contain enough residual milk protein to cause symptoms in highly sensitive subjects (3).
 
Undegradedβ-lactoglobulin has also been demonstrated in infant formulas (4). A study on tryptic peptides of a-lactalbumin confirmed the importance of conformational epitopes suggested by the heat lability of the protein (5).

References:

    1. Hoffman, D; Yamamoto, F; Geller, B; Haddad, Z. Specific IgE antibodies in atopic eczema. J Allergy Clin Immunol; 1975; 55: 256-267.
    2. Rolfsen, W; Tibell, M; Yman, L. Cow’s milk proteins as allergens and antigens. Allergol Immunolog Clinica (Madr); 1987; 2: 213.
    3. Frémont, S; Kanny, G; Bieber, S; Nicholas, P; Moneret-Vautrin, DA. Identification of a masked allergen, a-lactalbumin, in baby food cereal flour guaranteed free of cow’s milk protein. Allergy; 1996; 51: 749-754.
    4. Chiancone, E; Gattoni, M; Giampietro, PG; Ragno, V; Businco, L. Detection of undegraded b-lactoglobulins and evaluation of the molecular weight of peptides in hydrolysate cow’s milk formula. J Investig Allergol Clin Immunol; 1995; 5: 228-233.
    5. Maynard, F; Jost, R; Wal, JM. Human IgE binding capacity of tryptic peptides from bovine a-lactalbumin. Int Arch Allergy Immunol; 1997; 113: 478-488.

1999



Further Reading