Airway obstruction in adults with recurrent respiratory infections and IgG deficiency.

In 42 adults with recurrent respiratory infections (RRI) and common variable immunodeficiency or immunoglobulin G (IgG) subclass deficiency, the results of pulmonary function tests were related to factors apt to produce airway obstruction: serum concentration of IgG and IgG subclasses, various features of acute RRI (number/year, time from onset to diagnosis, episodes of pneumonia, etc) and type of chronic lung disease (smoking and nonsmoking related chronic bronchitis, episodic wheezing, and bronchiectasis). Compared with nonsmokers, usually less than 40 years of age, the patients above 40 had smoking-related chronic bronchitis and had obstruction (%FEV1/forced vital capacity [FVC] 55.3 +/- 8.1 vs 80.1 +/- 4.5), hyperinflation (residual volume 182.7 +/- 22.7 percent vs 109.7 +/- 8.8 percent of pred) hypoxemia (66.6 +/- 5.8 vs 83.4 +/- 4.2 mm Hg) and impaired carbon monoxide transfer (65.5 +/- 9.1 percent vs 93.3 +/- 5.8 percent). The features of acute or chronic RRI, the time from onset to diagnosis (< 10 yr in the entire group), the type of IgG deficiency or the serum concentration of the deficient protein did not correlate with substantial obstruction (FEV1/FVC < 70%). In conclusion, in adults with IgG deficiency and RRI for less than 10 yr, smokers with chronic bronchitis rather than nonsmokers develop substantial airway obstruction.