Interestingly, in contrast to the CD8+ T cell findings, although CD4+ T cells, CD56+ NK cells and NKT cells were analyzed simultaneously in the same sample, only the expression of TLR2/1 on the lung CD4+ T cells and the expression of TLR2 on the CD8+ NKT cells was significantly increased in the subjects with COPD (Figure 3, middle and right panels; data not shown for NKT cells). Here, CD4 is linked to chronic obstructive pulmonary disease.