[Usefulness of hypoallergenic rice (AFT-R 1) and analysis of the salt insoluble rice allergen molecule].

An involvement of rice allergy in development and exacerbation of recalcitrant atopic dermatitis (AD) has been suggested in some cases, and it has been also known that elimination diet of rice results in improvement of AD and reduction of the doses of steroid ointment and anti-allergic drugs used for the treatment. We prepared the hypoallergenic rice grain, AFT-R 1 (Allergen-free Technology Lab. Inc.-Rice 1), with alkali treatment from the rice material, Koshihikari, which is popular in Japan. Its usefulness was evaluated clinically and serologically. The serological study with IgE-ELISA showed that the major allergic protein were remarkably reduced to less than 1/6400 of them in the AFT-R 1. Then it was applied to the clinical trial, and evaluated as useful by the clinical effect in 14 (93%) out of 15 patients, who were diagnosed to have rice allergy by the elimination (in 15 case) and ingestion (in 12 cases) of the regular rice. The serum taken from the patient, whom the AFT-R 1 was evaluated as unuseful in the clinical trial, was shown to have IgE antibodies reactive to the remaining protein in AFT-R 1 by IgE-ELISA, and the 60 kd protein band was detected as an IgE-binding component of AFT-R 1 by IgE-immunoblotting with the same serum. This 60 kd rice protein was identified as ADP (UDP)-glucose-starch glycosyl transferase (EC: 2.4.1.21) by N-terminal amino acid analysis. These results indicated that AFT-R 1 is very useful as a substitute of rice in many AD patients with rice allergy, although IgE-binding component such as the 60 kd protein is remaining in one.