Allergen exposure leads to production of the specific IgE antibody and bronchospasm in atopic asthmatics. However, in adult cases with non-atopic asthma, the mechanism of asthma attack is still unknown. We observed that many adult asthmatics had fever and cold symptoms immediately before developing their first attack. Therefore, we measured the serum antibody titers against nine viruses (Influenza A and B, Adenovirus, RSV, Coxsackie B type 3, CMV, Parainfluenza type 1, 2, and 3), and analyzed their relationship with other clinical paremeters to elucidate the possible role of virus infection in inducing asthma attack. (1) No difference in antibody titers was observed between atopic and non-atopic asthmatics. (2) Steroid-dependent asthmatics had a higher antibody against CMV, and lower antibody against Coxsackie virus as compared with non-steroid dependent patients. (3) The anti-CMV antibody showed a significant correlation with the specific IgG antibody and lymphocyte blastogenesis to Candida antigen. (4) To examine the cross reactivity between Candida antigen and CMV, Candida antigen-specific-human monoclonal antibody was used but the result was negative. These findings suggest that the relationship between CMV and Candida is important in the pathogenesis of non-atopic adult asthmatics, although the mechanism is still unknown.