e204 nBos d 6, BSA Cow

Unexpected exposure

It is used in the manufacture of anti-wrinkle skin-tightener and is a basic protein for biological reactants. It may be used as a medium for in-vitro fertilisation techniques.

Direct or indirect contact with Bovine serum albumin often causes sensitisation.

For more detailed information, please see nBos d 4.

Allergen Exposure

Geographical distribution

Serum albumin is the main protein in mammalian blood tissue. It plays a very important role in the transport of nutritional substances into the system by virtue of its ability to bind with a large number of molecules.

Beef contains BSA and gamma globulin. These are heat-labile proteins found also in Cow's milk. BSA is a distinct milk allergen comprising approximately 1% of the total milk protein.

Environment

BSA is a protein found in Beef and in milk. It may be obtained from Bovine plasma collected in slaughterhouses, highly purified, and used in biochemistry, immuno-chemistry, haematology and microbiology, in all countries where these sciences are practiced. It is most often employed in the production of diagnostic test systems, as a growth medium for bacteria, and as a cell culture.

Bovine serum albumin occurs as a major allergen in Beef, and a minor allergen in Cow's milk. Beef allergic individuals are at risk of being allergic to Cow's milk and vice versa.

BSA and OSA (Ovine serum albumin) are important Beef and Lamb allergens. They have similar proteic sequences and allergenic properties (6).

Thiomucase (a mucopolysaccharidase obtained from Ovine tissues and used mainly to facilitate the diffusion of local anaesthetics and in the treatment of cellulitis) is partially cross-reactive with BSA, Cat dander and Sheep dander (7).

IgE-mediated reactions

Food allergy (Beef/milk), asthma, allergic rhinitis and anaphylaxis often occur following exposure to BSA (8) . In Beef allergy, Bovine serum albumin (BSA) and actin have been reported to be the proteins most frequently involved in binding with the circulating IgE (9-10).

BSA can also be an occupational allergen. Recurrent rhinoconjunctivitis and wheezing following repeated exposure to purified lyophilised Bovine serum albumin (BSA) have been described in a laboratory technician (11).

Eosinophilic gastroenteritis is a disease characterised histologically by an eosinophilic infiltration of the gut. A study reports on a 22-year-old man in whom gastrointestinal symptoms first appeared in childhood. He had high IgE blood levels, and his skin-specific IgE test was positive to Bovine, Pig, and Lamb sera. The patient's serum contained specific IgE to Bovine serum albumin. The authors report that their data suggests a possible role for IgE-mediated hypersensitivity mechanisms in the pathogenesis of eosinophilic gastroenteritis (12).

The proliferative responses of peripheral blood mononuclear cells to Ovalbumin or Bovine serum albumin in children with atopic dermatitis who are sensitive to Hen's egg or Cow's milk have been reported to be significantly higher than the response of peripheral blood mononuclear cells of healthy children and Hen's egg- or Cow's milk-sensitive children with immediate symptoms (13-14).

A number of studies have reported severe allergic reactions during artificial insemination as a result of exposure to BSA present in the growth medium.

A 33-year-old woman without a history of atopic diseases or drug allergies developed a severe anaphylactic reaction with asthma, vomiting, itching, generalized urticaria, and angioedema during artificial insemination with her husband's sperm. The sperm-processing medium contained Bovine serum albumin (BSA). Bovine serum albumin is present in the follicle-rinsing fluid and in the medium used for embryo culture. The authors point out that artificial insemination with fluid containing potential allergens can represent an unnecessary risk for atopic females, even in the absence of prior clinical symptoms of allergic diseases (15-18).

Other reactions

A 27-year-old woman with severe recurrent angioedema and urticaria since the age of 5 years was found to have high levels of circulating immune complexes in the peripheral blood. These immune complexes contained antibodies against Bovine serum albumin. Elimination of Bovine products from the diet resulted in the disappearance of immune complexes within 2 days. Reintroduction of Bovine products to the diet resulted in the reappearance of these immune complexes within 24 hours (19).

In an in vitro fertilization (IVF) program in which a medium containing Bovine serum albumin (Menezo's medium) was employed for rinsing follicles, 5 (15%) of 32 women involved in the IVF program developed a symptom complex compatible with serum sickness within 8-12 days after oocyte retrieval by echographic puncture. All the patients had specific IgG antibodies against BSA, and intradermal skin testing with BSA and Menezo's medium were positive. The presence of specific IgE against BSA in serum could not be demonstrated. The authors suggest that this is probably due to the presence of high levels of specific IgG antibodies, which can interfere in the RAST procedure (20).