To clarify the pathogenesis of late onset intractable asthma (LOIA), 102 asthmatics were classified into early (<40y.o.) and late onset asthma (>40y.o.), or intractable and non-in-tractable asthma. Clinical and allergic examinations were evaluated in each asthma group. Sixty nine percent of the late onset asthmatics had perennial type attacks. IgG-as well as IgE-mediated allergic reactions were suggested by the findings of immediate skin reaction, IgE RIST and RAST score to Candida allergen and reactivity of basophils to anti-immunoglobulin antisera in LOIA. Neutrophils in bronchoalveolar lavage fluid increased significantly in LOIA as compared with the early onset intractable asthma (EOIA) groups (p<0.05). In the pulmonary function test, a striking fall of % V25 was observed in both EOIA ans LOIA. The chest X-ray film frequently revealed microndular shadows in LOIA. Marked morphological changes in the transbronchial lung biopsied specimens were observed in the late onset asthmatics. These findings suggest that a non-IgE reaction, neutrophil infiltration in the local allergic site and histolpgical changes of lung tissue lead to LOIA.
transbronchoscopic lung biopsy