A clinical evaluation of the Rast Procedure for IgE antibodies

Abstract

A large number of people in this country are afflicted with allergic disorders of varying degrees of severity. These disorders can range from mild hayfever to severe asthmatic conditions. Two chemical entities involved in the manifestation of these disorders are the antigens and the antibodies. The antigens, like pollen, stimulate the production of antibodies to form antigen-antibody complexes. The antibody primarily responsible for the allergic response is called Immunoglobulin E, IgE. The exact mechanism of action of the IgE is unknown at this time, but it is thought that it attaches itself to the cells in the body's connective tissue and stimulates the production of various chemical mediators. One of the prime chemical mediators is histamine which is the agent primarily responsible for the stuffy nose and congestion associated with allergies. The diagnosis of allergies is accomplished through the use of a clinical history and various diagnostic methods. Two diagnostic methods commonly used are skin and provocation testing. Both of these test types are time consuming , inconvenient, uncomfortable and in the case of provocation testing, potentially harmful . The Radioallergosorbent Test (RAST) and the Radioimmunosorbent Test (RIST) are two new analytical tools that show great promise in allergy diagnosis . Both techniques involve the measurement of allergen specific or total IgE by the use of 125I coupled to either an anti-IgE or IgE-125I respectively and the measurement of the resulting radioactivity. The evaluations conducted at YSU were done on twenty-four patients of a local allergist and seven volunteers from YSU and the Youngstown Hospital Association . The RAST was performed on all patients utilizing a combination of eight possible allergens and the RIST was performed on seven patients. The results of the RAST were compared with information received from the allergist which included clinical comments and skin test evaluations. Four of the eight allergens were used and two of the four had a regression analysis done on them . The YSU correlation results were compared with literature values. It was found that the RAST results compared very favorably. The RIST results were also compared with literature values. While the values arrived at by YSU varied widely, they were within normal ranges . A brief cost analysis showed that the RAST and RIST compared favorably with the costs of other laboratory tests and might be implemented in the series of tests possible in a clinical laboratory. As a result of this evaluation, the RAST and RIST can be seen to be a valuable diagnostic tool in allergy evaluations. The technique is not difficult or overly expensive and can serve as a valuable addition to the techniques available for the diagnosis of allergies.