Background: Infections continue to be the leading aetiology of bronchiectasis in developing countries like India. Among non-infectious cases, the majority will have no identifiable cause despite extensive evaluation. Recently, immunodeficiency has been recognized as an important aetiology, but data on its prevalence remain rather sparse.
Objectives: The objective of this study is to evaluate the prevalence of humoral immunodeficiency in a cohort of adults with bilateral bronchiectasis with no apparent aetiology.
Methods: This is the single-site study from Christian Medical College (Vellore, India) of adults with HRCT-proven non-infectious bronchiectasis. Humoral immunity was assessed through quantitative analysis of immunoglobulins and IgG subclass levels.
Results: Among 158 cases, immunoglobulin deficiency was found in 15%. Low IgM was the most predominate finding (7%), followed by common variable immunodeficiency (3%) and low IgA (2.5%). In addition, IgG subclass deficiency was found in 5%. In 53% of cases, no specific aetiology could be identified.
Conclusion: Humoral immune deficiency is present in a significant proportion of patients with non-infectious bronchiectasis. Routine measurement of serum immunoglobulins should therefore be considered as part of the evaluation.
Keywords: Bronchiectasis; IgG subtypes; humoral immunity; immunodeficiency.