[Immunological approach to asthmatic disease (author's transl)].

Research into the environmental factors in the aetiological diagnosis of asthma is a fundamental measure which must direct complementary test and therapy. Extrinsic asthma is mostly found in young people, with atopic antecedents. Immunological study is based on the clinical history and skin tests (IgE dosage, in vitro tests and provocation tests are difficult to apply in epidemiology due to their high cost). In children 3/4 of asthma cases are extrinsic. Differential diagnosis is especially a problem with rhinitis. There is only a small percentage of cases of non atopic extrinsic asthma which can bring other immunological mechanisms into play. So-called intrinsic asthma (late onset asthma, with continuous dyspnea, corticodependent) is mostly observed in adults. The age has an influence on the severity of the attacks, the curve of asthma with permanent dyspnea being a function increasing with age, whereas that of less severe asthma is a function decreasing with age. The role of extrinsic factors does not seem important in this category of asthmatics (10 to 25% according to the statistics). Immunofluorescence studies of the bronchial mucosa show up the possibility of local immunological reactions, whether specific or not (frequent presence of the C3 complement). This means that the immunologist can, in many cases of asthma, help the epidemiologist to define and to understand the physiological mechanisms of the disease.