[Critical study of methods for the diagnosis of allergic asthma]

Abstract

A search for an allergic cause in asthma is fundamental to the diagnosis. Typically it is based on: A clinical history. Specific cutaneous and inhaled provocation tests which can produce a possible reaction (early and delayed) which are of great pathophysiological and therapeutic interest. In vitro tests (which enable the different phases of the allergic reaction to be distinguished) to know the serum IgE antibody levels (total IgE, specific IgE and their fixation to cell receptors) cell tests on the degranulation of basophils and the dosage of chemical mediators: histamine, leukotrienes, prostaglandins, P.A.F. in the serum or in the bronchial alveolar lavage liquid, from the study of cells or tissue samples. In this regard the authors stress two recent techniques enabling direct access to bronchial tissue and the pulmonary parenchyma, which are bronchoalveolar lavage and bronchial biopsy, both are possible today by using a fibroscope. The broncho-alveolar lavage still remains in the research area, and is not always well tolerated in asthmatics. It already allows a better definition of the major allergic cytological and biochemical components in asthma (IgE, IgA, albumin, phospholipids, mast cells and eosinophils). Bronchial biopsies with ultra-structural studies, and above all immunopathology (by immunofluorescent techniques and peroxidase stains) enable groups of asthmatics to be uncovered who were considered as non-allergic by the unsuspected intervention of hypersensitivity mechanisms to IgE (the presence of cells carrying IgE); these biopsies enable the importance of inflammatory factors to be confirmed and equally to establish the prognosis in certain asthmatics by the degree of irreversibility of the lesions (fibronectin).(ABSTRACT TRUNCATED AT 250 WORDS)