[Clinical relevance of immunoglobulin subclasses in children with chronic pulmonary diseases].

In 52 children (age 4-19.5 years; 17 female, 35 male) with chronic chest symptoms IgG-Subclass levels were measured by radial immunodiffusion techniques. Thirteen children had proven bronchiectasis, 22 chronic bronchitis and 17 steroid dependent asthma bronchiale. Cystic fibrosis, alpha-1-antitrypsin deficiency, tuberculosis and chronic foreign bodies were excluded in each patient; all of them showed normal levels of total IgG. Four children (3 with bronchiectasis, one with steroid dependent asthma bronchiale) had a complete lack if IgG4. In two children with chronic bronchitis one showed fluctuating levels of IgG2 and IgG4 and another deficiency of IgG3. All patients with an isolated IgG4 deficiency were treated with immunoglobulins. Of 3 patients with bronchiectasis one improved, two remained unchanged as shown by positive sputum cultures and of chronic chest symptoms. One patient with steroid dependent asthma bronchiale markedly improved during immunoglobulin therapy. It is concluded, that early screening of IgG subclass deficiency is indicated in all children with chronic chest symptoms.