Occupational allergy caused by cow dander: detection and identification of the allergenic fractions.

We describe two cases involving cow farmers, both males, one aged 28 and the other 45, who attended our center because his presented symptoms of rhinoconjunctivitis and asthma with 18 months and 4 year of evolution respectively, related to this laboral environment. The study included the following tests: skin tests (prick tests) to inhalant allergens (mites, pollens, moulds, dog and cat epithelium), foods, cow epithelium-dander, cow serum, beef and milk proteins. We determined the total seric IgE, specific IgE (RAST-CAP System) to cow meat and cow dander. Nasal provocation test with freeze-dried biological standardized extract of cow epithelium-dander were carried out. We observed the symptoms and realized control with a previous active computerized rhinomanometry. Cow dander proteins used for the provocation test were separated by means of SDS-PAGE or isoelectric focusing (IEF). The allergenic component were identified by immunoblotting with the patients' serum. The skin tests were positive to cow dander, and negative to the other allergens tested, including cow serum, cow milk and beef. The seric IgE were 383 and 477 kU/L, and the RAST was positive to cow dander, 20.10 and 36.4 kU/L (class 4). The provocation test were positive with a concentration of 500 SBU. We observed that the IgE of the two patients reacted with the same allergens: 3 major bands were identified with MW of 11, 15, 62.3 kDa. All these bands correspond to protein with acid pl.