Current smoking status is associated with reduced sputum immunoglobulin M and G expression in COPD

The relationship between smoking status and total immunoglobulin levels in patients with COPD is not fully understood. Decreased immunoglobulin levels have been observed in patients with COPD [1–4], a disease largely attributed to current or former smoking, and cigarette smokers [5, 6]. These studies focused predominately on serum (systemic) or salivary (upper respiratory tract) immunoglobulins. Levels of immunoglobulins in induced sputum, a more direct measure of airway immunoglobulins, are less well studied. Given the vital role immunoglobulins perform in microbial defence and tissue homeostasis, we assessed airway immunoglobulins in induced sputum of smokers and patients with COPD. Current smoking status in subjects with mild to moderate COPD was associated with reduced total induced sputum IgM and IgG. This reduction in immunoglobulins was independent of inhaled corticosteroid use. https://bit.ly/2FtBg1t