Abstract
OBJECTIVES: Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality around the world. Preliminary studies have evaluated the association between innate immunity including Toll-like receptors (TLRs) and airway samples of patients with COPD. The role of TLRs in peripheral blood neutrophils is poorly understood. Hence, this study aimed to investigate the role of TLR2 and TLR4 in peripheral blood neutrophils of COPD patients. METHODS: A total of 101 COPD cases and an equal number of healthy controls participated in this case-control study. Peripheral blood neutrophils were isolated from all participants and cultured for 24 hours through lipopolysaccharide (LPS) stimulation. The gene expressions of TLR2 and TLR4 were assessed by real-time polymerase chain reaction. The protein levels of interleukin (IL)-8 and matrix metalloproteinase (MMP)-9 were measured in neutrophils cell culture supernatants using enzyme-linked immunosorbent assay (ELISA). RESULTS: The levels of IL-8 and MMP-9 were significantly higher in patients with COPD compared to healthy controls. Similarly, the gene expression of TLR2 and TLR4 were increased in LPS stimulated peripheral blood neutrophils of patients with COPD. Smoke pack years was positively correlated with IL-8 levels and negatively correlated with forced expiratory volume in the first second % (r = -0.33; p = 0.023) and FEV1/forced vital capacity (FVC) (r = -0.27; p = 0.011). CONCLUSIONS: The increased expression of TLR2 and TLR4 suggests its role in disease pathogenesis of COPD. Smoke pack years was negatively associated with spirometric parameters in COPD patients. This may help to predict the smokers without COPD who risk developing the condition in the future.