In our proposed hypothesis (2005), the leading role in the development attacks of breathlessness in patients with bronchial asthma given to hyperactivity of the bronchi. The specific immune response in the bronchi walls, realized for the destruction of tissue forms fungi of the genus Paecilomyces and limit their proliferation in lung tissue.Eosinophils play an important role of effector cells in the antibody-cell - mediated cytotoxicity (see appendix).