Current smoking status is associated with reduced sputum immunoglobulin M and G expression in chronic obstructive pulmonary disease.

The relationship between smoking status and total immunoglobulin (Ig) levels in patients with chronic obstructive pulmonary disease (COPD) is not fully understood. Decreased Ig 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) Igs. Levels of Igs in induced sputum, a more direct measure of airway Igs, are less well studied. Given the vital role Igs perform in microbial defence and tissue homeostasis, we assessed airway Igs in induced sputum of smokers and patients with COPD. Footnotes This manuscript has recently been accepted for publication in the European Respiratory Journal . It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article. Conflict of interest: Mr. Cass has nothing to disclose. Conflict of interest: Dr. Yang has nothing to disclose. Conflict of interest: Dr. Xiao has nothing to disclose. Conflict of interest: Joshua McGrath has nothing to disclose. Conflict of interest: Mr. Fantauzzi has nothing to disclose. Conflict of interest: Ms. Thayaparan has nothing to disclose. Conflict of interest: Dr. Wang has nothing to disclose. Conflict of interest: Dr. Liang has nothing to disclose. Conflict of interest: Dr. Long has nothing to disclose. Conflict of interest: Dr. Stevenson reports other from Johnson & Johnson, outside the submitted work;. Conflict of interest: Dr. Chen has nothing to disclose. Conflict of interest: Dr. Stampfli reports grants from Canadian Institutes of Health Research , grants from RespiVert Ltd. part of Janssen Pharmaceuticals, during the conduct of the study; grants from RespiVert Ltd. part of Janssen Pharmaceuticals, personal fees from AstraZeneca, personal fees from Boehringer Ingelheim, outside the submitted work;.