Isolation and characterization of a heat-resistant beef allergen: myoglobin.

BACKGROUND

Meat allergy is rarely reported. Most of the described cases are sensitizations to bovine serum albumin.

OBJECTIVE

The aim of the study was to describe a case of allergy to a new meat allergen and, after its characterization.

METHODS

A 35-year-old nonatopic female with allergic episodes after ingestion of several types of meat was studied. Skin tests (prick and prick-to-prick); total and specific immunoglobulin E (IgE) determination; sodium dodecyl sulphate-polyacrylamide gel electrophoresis and specific IgE determination by immunoblotting under different conditions were performed. A 17-kDa allergen was semipurified by ethanol fractionation and its amino-terminal sequence was determined. The existence of specific IgE directed to this protein was studied by immunoblot in 80 atopic patients.

RESULTS

The patient showed specific IgE antibodies to a 17-kDa protein. During the isolation of this allergen it was found that a 70-90% (vol/vol) ethanol concentration was able to purify the protein. The characterization revealed that it was a heat-resistant protein without disulfide bonds. N-terminal amino acid sequence (16 residues) showed identity with myoglobin. The study of specific IgE to this allergen among atopic patients showed that it was recognized by about 1% of the subjects.

CONCLUSIONS

We describe a case of meat allergy caused by myoglobin. This is the first described case of monosensitization to this protein.