To clarify the pathogenesis of intractable asthma, clinical features, allergic examinations, pulmonary functions and histological finding were evaluated in 27 intractable asthmatics compared with 33 non-intractable asthmatics. Almost all of the intractable asthmatics had chronic and perennial asthma attacks and also had highly frequent episodes of respiratory infection. IgG-as well as IgE-mediated allergic reactions were proved by the findings of skin reaction, IgE RAST score, precipitating antibody and reactivity of basophils to anti-immunoglobulin antisera in the intractable asthmatics but not in the non-intactable asthmatics. Neutrophils of BALF and peripheral blood increased markedly in the intractable asthmatics as compared with the non-intractable asthmatics. The fall of % V(25) on flow volume curve in the intractable asthmatics, indicated small air way obstruction. Micronodular shadows on the chest X-ray film were frequently seen in the intractable asthmatics. Many histological findings were shown on lung specimens obtained by TBLB in the intrac-table asthmatics. These findings indicate that multiple factors of allergic reaction mediated by IgG, migrated neutrophils and organic changes of lung tissue lead to severe and intractable asthma attack.
transbronchoscopic lung biopsy