Pulmonary interstitial disease in Ig deficiency

Study objectives: To determine the frequency and type of interstitial lung disease (ILD) in consecutive subjects with symptomatic Ig deficiency. Patients: One hundred forty-eight consecutive subjects with repeated respiratory infections and Ig deficiency. Measurements: Ig classes and IgG subclasses (IgGSCs), the response to vaccination, pulmonary function tests, chest radiography, CT scan, Ga scan and, when possible, BAL and lung biopsy. Results: Twenty-nine of 148 subjects (19 men and 10 women aged 18 to 72 years) had evidence of ILD. In 20 subjects, no cause of ILD was apparent. The remaining nine cases were ostensibly due to identifiable causes. Twenty subjects had IgGSC deficiency, 8 subjects had common variable immunodeficiency, and 1 subject had combined IgM plus IgGSC deficiency. No isotype deficiency was consistently related to a specific ILD. After administration of IV Ig, eight subjects, all with IgGSC deficiency, improved clinically, physiologically, radiologically, and occasionally histologically, regardless of immunologic or radiologic features. In this selective sample, the prevalence of ILD in consecutive subjects with recurrent respiratory infections and Ig deficiency (29 of 148 subjects; 19.6%) was higher than in the general population (0.8%; p < 0.05). Conclusions: ILD in Ig deficiency is frequent and usually involves IgGSC deficiency.