Increased Numbers of NK Cells, NKT-Like Cells, and NK Inhibitory Receptors in Peripheral Blood of Patients with Chronic Obstructive Pulmonary Disease

T cells and B cells participate in the pathogenesis of COPD. Currently, NK cells and NKT cells have gained increasing attention. In the present study, 19 COPD patients and 12 healthy nonsmokers (HNS) were recruited, and their pulmonary function was assessed. The frequencies of CD3(+) T, CD4(+) T, CD8(+) T, B, NK, and NKT-like cells were determined using flow cytometry. The frequencies of spontaneous and inducible IFN-γ (+) or CD107a(+) NK and NKT-like cells as well as activating or inhibitory receptors were also detected. The potential association of lymphocyte subsets with disease severity was further analyzed. Significantly decreased numbers of CD3(+) and CD4(+) T cells, and the CD4(+)/CD8(+) ratio, but increased numbers of CD3(−)CD56(+) NK and CD3(+)CD56(+) NKT-like cells were observed in COPD patients compared to HNS. The frequencies of inducible IFN-γ-secreting NK and NKT-like cells were less in COPD patients. The frequencies of CD158a and CD158b on NK cells and CD158b on NKT-like cells were greater. The frequency of CD158b(+) NK cells was negatively correlated with FEV(1)% prediction and FEV(1)/FVC. Our data indicate that COPD patients have immune dysfunction, and higher frequencies of inhibitory NK cells and NKT-like cells may participate in the pathogenesis of COPD.