Summary Sera from 119 patients with possible food allergies were tested against a panel of thirteen food allergens by the RAST technique. The results were compared with in vivo tests. 79% of foods causing symptoms gave a positive RAST to the specific food. Symptoms were grouped according to their time of appearance after taking the food; ‘immediate’ up to 1 hr and ‘non‐immediate’ more than 1 hr afterwards. Almost all those with ‘immediate’ symptoms were already aware of the foods causing them and there was a 100% correlation of the RAST result with these. Only a few of those with ‘non‐immediate’ symptoms were previously aware that these foods were responsible, and 64% of these gave a positive RAST. The majority of patients with a positive RAST result had total IgE in excess of 300 u/ml, had specific IgE antibodies against one or more common inhalant allergens, were under the age of 30 years and had a combination of asthma and eczema. We found the RAST method a useful and safe guide upon which to base a clinical investigation of food allergy, especially for patients whose symptoms appeared more than 1 hr after the food and in whom the relationship between their symptoms and food was not apparent. The RAST technique was surprisingly successful in identifying the foods which caused these ‘non‐immediate’ symptoms.

Serum albumin was found to be an important allergen in horse epithelia extracts. The albumin concentration varied considerably, depending on the raw material used for the preparation of the allergen extracts. In addition to serum albumin, two allergenic proteins were demonstrated in horse dandruff. The molecular weights of these allergens were calculated to be about 38,000 and 22,000, respectively. The pi of the latter was 4.2. Fifty sera from allergic patients were studied by means of the radioallergosorbent test (RAST) using horse epithelia extract, horse dandruff extract, a purified horse dandruff allergen and horse serum as test allergens. About 24% of the patient sera studied were found to contain IgE specific to horse serum proteins. IgE specific to horse dandruff proteins was found in about 62% of the patient sera, while the rest, about 14%, apparently contained IgE specific to both kinds of allergens.

Allergens from dog serum and extracts of dog hair, dandruff and skin scrapings were studied with respect to some physico-chemical and immunological properties. Serum albumin was found to be an important allergen present in high concentration in epithelia extracts. At least one additional serum protein was found to be a potent allergen.

IgE-antibody analysis is a major diagnostic procedure and a primary tool in allergological research. The determination of sensitization frequencies and antibody concentrations against allergens of defined sources provides critical information for the estimation of the relative importance of food and environment in clinical allergy. True quantitation is essential and requires assay designs providing allergen excess and mass unit calibration. Standardized and reproducible methods show geographic and culture dependent differences between patient populations and contribute to the quality of diagnosis and treatment of allergic disease.

Skin tests and estimation of specific IgE-antibodies by the RAST are evaluated as diagnostic procedures in bee sting hypersensitivity with the followiny extracts. (2) With bee venom results of skin tests and RAST correspond in 82%, with bee wholebody extracts in 68%. (3) Both with skin tests and the RAST with bee venom a good discrimination between patients with bee sting hypersensitivity and non-allergic controls is observed. Skin tests with bee venom are somewhat more sensitive than bee venom-RAST. (4) With the careful skin test procedure chosen, no adverse reactions were observed.