Antibody deficiencies with normal IgG in adults with Non-cystic fibrosis bronchiectasis or recurrent pneumonia: Cross-sectional study

Abstract

Background Inborn errors of immunity, mainly Predominantly Antibody deficiencies with normal IgG levels, are unrecognized in adults with lung diseases such as bronchiectasis or recurrent pneumonia. Objective To determine IgM, IgA, IgG2 subclass deficiencies, and Specific antibody deficiency (anti-pneumococcal polysaccharide antibodies) in adults with non-cystic fibrosis bronchiectasis or recurrent pneumonia. Methods Cross-sectional study. Consecutive patients with non-cystic fibrosis bronchiectasis or recurrent pneumonia were recruited in Cali, Colombia. IgG, IgA, IgM; IgE, IgG2 subclass, and IgG anti-pneumococcal serum levels were measured. Results Among the 110 participants enrolled, Antibody deficiencies with normal serum IgG levels were found in 11(10%) cases. IgA deficiency (3 cases), IgM deficiency (2 cases), and IgG2 deficiency (2 cases) were the most frequent primary immunodeficiencies. In addition, IgG2+IgA deficiency, Ataxia-telangiectasia, Hyper-IgE syndrome and Specific Antibody Deficiency(anti-polysaccharides) were found in one case each. Conclusions Predominantly antibody deficiencies with normal IgG levels are an important etiology of non-cystic fibrosis bronchiectasis and recurrent pneumonia in adults.