[Immunoglobulin G subclass deficiency in patients with asthma and chronic obstructive bronchitis].

In 99 patients with asthma or chronic obstructive bronchitis immunoglobulins and immunoglobulin-G subclasses were measured to characterize the frequency of humoral immune deficiencies. 26 patients had decreased serum levels in one or two IgG subclasses. So IgG-subclass deficiency is a common finding in patients with asthma and obstructive bronchitis. Treatment with corticosteroids seems to promote low IgG-subclass levels, but cannot fully explain alterations of IgG subclasses. Today IgG-subclass deficiencies are regarded as an important factor in the susceptibility to recurrent infections. We think, variation in IgG subclasses may have further effects on the noninfectious inflammatory processes of asthma and obstructive bronchitis.