Various antigens such as mite and fungi have been known to provoke bronchoconstriction in patients with bronchial asthma. The allergic mechanisms of asthmatic attack induced by these antigens were analyzed to clarify the role of cellular immunity in the pathogenesis of bronchial asthma. Mite and Candida antigens were applied to lymphocyte blastogenesis in asthmatic patients. Both lymphocytes in bronchoalveolar lavage fluid (BALF) and in peripheral blood of asthmatic patients responded significantly to mite and Candida antiten. Furthermore, BALF lymphocytes of patients with non-atopic and intractable asthma showed higher responses against Candida antigen than those of patients with atopic and non-intractable asthma, while peripheral blood lymphocytes showed a higher response against mite antigen in patients with atopic and non-intractable asthma. These findings indicate that lymphocytes in lugns sensitized with Candida antigen might play an important role in the pathogenesis of non-atopic and intractable asthma.