Blood lymphocyte subpopulations in extrinsic and intrinsic asthmatics

Blood leukocyte numbers and proportions of T lymphocyte subsets were studied in extrinsic asthmatics (EA), intrinsic asthmatics (IA), IA systemically treated with corticosteroids (IA + C), and in age-matched control subjects. The EA and IA showed an increased number of eosinophils. During corticosteroid therapy of IA, the eosinophil number remained elevated, whereas there was a slight decrease in the number of circulating lymphocytes. The proportion of T cells of the suppressor/cytotoxic phenotype carrying the Leu-2a antigen was significantly lower in the IA than in all other groups. In the IA + C group, the proportions of Leu-3a/3b and Leu-2a positive T lymphocytes returned to normal, although the patients still exhibited asthmatic symptoms. These findings suggest that cellular immunologic factors might be involved in the pathogenesis of intrinsic asthma.