IGG DEFICIENCY IN ADULTS WITH RECURRENT RESPIRATORY-INFECTIONS

Total IgA, IgM, IgG, and IgG subclasses were measured in 136 consecuti ve adults with recurrent respiratory infections. Sinus and chest radio graphs were also obtained. IgG antibodies to H. influenzae and tetanus toxoid were determined in 27 immunodeficient subjects. Fifty-eight of the 136 were deficient in some immunoglobulin isotype, three in IgA, three in IgM, and 52 in total IgG or one or more IgG subclasses. The m ost common IgG deficiencies were single IgG subclass deficiencies, par ticularly IgG3 or IgG4, and a mild decrease in total IgG (between 450 and 650 mg/dL). In 21127 subjects with IgG deficiency, the response to booster immunization was blunted, even when IgG1 and IgG2 were normal . Thirty-eight patients were smokers, 3 7 being >40 years of age at th e onset of respiratory infections. Twenty patients were nonsmokers, 19 being <40 years of age at the onset. In conclusion, adults with recur rent respiratory infections frequently have some variant of IgG defici ency, often associated with a functional impairment of specific antibo dy response. Smoking may represent a risk factor for IgG deficiency in adults.