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Keywords:

  • anaphylaxis;
  • food allergy;
  • ovine serum albumin (OSA);
  • lamb meat

Food anaphylaxis is one of the most common causes of anaphylactic reactions in industrialized countries. Meat allergy represents, with an incidence of 8.2%, a rather small proportion of all food allergies (1). Amongst those, about 10% are caused by lamb meat (1).

A 32-year-old Turkish female patient repeatedly developed generalized urticaria and angioedema after eating beef and lamb meat without food additives or spices simultaneously. Since then, the patient has consumed beef, milk products and milk without any complications. Because of her religious background, she was not exposed to pork.

Total IgE and antigen-specific IgE (kU/l) were determined by the CAP System (Pharmacia, Freiburg, Germany). An allergen-specific immunoblot was performed in order to identify ovine serum albumin (OSA) as the major allergen or to detect so far unknown antigens.

Specific IgE was detected against lamb, beef, pork, casein and beef lactoferrin. Several lamb-specific IgE-binding protein bands between 18 and 200 kDa with strongest signalling between 22 and 50 kDa could be detected. In a control group with pooled sera of six healthy volunteers, no lamb-specific IgE-reactive bands were found. Skin-prick tests for milk, milk products and whole egg were negative. Skin-prick tests for boiled lamb meat showed a positive reaction with a wheal of >3 mm. After the ingestion of 9 g of boiled lamb meat, an anaphylactic reaction with generalized pruritus, erythema on the chest and dyspnoea occurred within 30 min.

Interestingly, in this case, using immunoblotting with the serum of the patient, we could not detect specific IgE for the 67 kDa OSA protein, but for several other so far not characterized bands, which may represent previously unknown proteins responsible for lamb meat allergy. However, further identification of the antigens of the positively tested bands and the causal role of these proteins in the anaphylactic reaction remains to be investigated. In 50% of beef allergies, a cross-reactivity is described between serum albumin of beef and lamb (2). Ayuso et al. (3) showed that patients with a suspected beef allergy have an IgE reactivity directed against meat proteins. This reactivity is mainly directed against a protein of 160 kDa, which was identified as bovine IgG. A cross-reactivity between lamb and beef exists, indicating similar epitopes in beef and lamb IgG antibodies. The specific IgE against common milk allergens such as beef lactoferrin and casein, have no clinical relevance, if milk and milk products can be tolerated. In our case, specific IgE was detected against lamb, beef and pork. Interestingly, only the ingestion of lamb meat caused anaphylactic reactions, beef was well tolerated and pork avoided by the patient because of her religion.

For patients with a history of anaphylactic reaction to meat, one should first rule out an allergy or intolerance to penicillin, papain, nitrates or nitrite salts, as they may be associated with angioedema and anaphylaxis (4, 5). It is noteworthy that some cases of anaphylactic reactions, upon meat ingestion, have been observed without positive skin-prick tests or any detectable specific IgE (6). Therefore, after exclusion of allergy to penicillin or an intolerance of preservatives, the diagnosis of a given meat allergy has to be confirmed by oral provocation test.

Taken together, an immediate-type allergy to meat, especially lamb meat, is rare, but it is important to diagnose this to prevent cross-reactivity.

References

  1. Top of page
  2. References
  • 1
    Wuthrich B. Allergy to meat proteins in adults. Allergologie 1996;19: 130134.
  • 2
    Restani P, Fiocchi A, Beretta B, Velina T, Giovannini M, Galli CL. Meat allergy: III – Proteins involved and cross-reactivity between different animal species. J Am Coll Nutr 1997;16: 383389.
  • 3
    Ayuso R, Lehrer SB, Lopez M, Reese G. Identification of bovine IgG as a major cross-reactive vertebrate meat allergen. Allergy 2000;55: 348354.
  • 4
    Hawkins CA, Katelaris CH. Nitrate anaphylaxis. Ann Allergy Asthma Immunol 2000;85: 7476.
  • 5
    Jäger L, Wüthrich B. Nahrungsmittelallergien und –intoleranzen. München: Urban & Fischer, 2002.
  • 6
    Chua YY, Bremner K, Llobet JL, Kokubu HL, Collins-Williams C. Diagnosis of food allergy by the radioallergosorbent test. J Allergy Clin Immunol 1976;58: 477482.