Although we also detected expression of multiple TLRs on lung CD4+ T cells, the near complete lack of their increased expression on this cell type in COPD, relative to age-matched smokers with preserved spirometry, implies either that the regulation or significance of TLR expression on CD4+ lung T cells, or the role of that subset itself, differs in COPD from that of lung CD8+ T cells. Here, CD4 is linked to chronic obstructive pulmonary disease.