Effects of Immunoglobulin Replacement on Asthma Exacerbation in Adult Asthmatics with IgG Subclass Deficiency

Purpose: Recurrent respiratory tract infection is a common manifestation of primary immunodeficiency disease, and respiratory viruses or bacteria are important triggers of asthma exacerbations. Asthma often coexists with humoral immunodeficiency in adults, and some asthmatics with immunoglobulin (Ig) G subclass deficiency (IgGSCD) suffer from recurrent exacerbations. Although some studies suggest a benefit from Ig replacement, others have failed to support its use. This study aimed to assess the effect of Ig replacement on asthma exacerbation caused by respiratory infection as well as the asthma control status of adult asthmatics with IgGSCD. Methods: This is a multi-center, open-label study of adult asthmatics with IgGSCD. All patients received monthly intravenous immunoglobulin (IVIG) for 6 months and were evaluated regarding asthma exacerbation related to infection, asthma control status, quality of life, and lung function before and after IVIG infusion. Results: A total of 30 patients were enrolled, and 24 completed the study. Most of the patients had a moderate degree of asthma severity with partly (52%) or uncontrolled (41 %) status at baseline. IVIG significantly reduced the proportion of patients with asthma exacerbations, lowered the number of respiratory infections, and improved asthma control status, compared to the baseline values (P<0.001). The mean asthma-specific quality of life and asthma control test scores were improved significantly (P= 0.009 and P= 0.053, respectively); however, there were no significant changes in lung function. Conclusions: IVIG reduced the frequency of asthma exacerbations and improved asthma control status in adult asthmatics with IgGSCD, suggesting that IVIG could be an effective treatment option in this population.