Three children, two boys aged 16 and 11 years and a girl aged 16 years, with symptoms resembling asthma had been treated for years with inhaled corticosteroids and beta 2-sympathicomimetics without satisfactory results. It was found that the antibody production after vaccination with 23-valent pneumococcal vaccine was impaired. The symptoms diminished during maintenance treatment with antibiotics in two children and with intravenous immunoglobulins in one. In patients with recurrent respiratory problems, but no specific history of asthma, immunological investigation is warranted, especially in patients whose 'asthma' is accompanied by respiratory infections. When treated for their immunodeficiency these patients show remarkable improvement and the need for steroids often disappears.