Table 2.

Main characteristics of the studies on patients with chronic obstructive pulmonary disease

Author	Year	Country	COPD patient and Controls	Inflammatory marker and laboratory measurement
Higashimoto	2009	Japan	COPD was diagnosed when the post-bronchodilator FEV1/forced vital capacity (FVC) ratio was less than 70% (GOLD stages IeIV). A total of 96 patients with COPD were recruited from patients seen in the Department of Internal Medicine of the Wakayama Medical University Kihoku Hospital	Serum CRP was measured by immune nephelometry using the TBA-200FR NEO system, with a lower detection limit of < 0.030 mg/dl. Serum α1-antitrypsin (α1-AT) was also determined using immune nephelometry. Tumor necrosis factor (TNF)-α, interleukin (IL)-8, IL-6, TGF-β1, neutrophil elastase, matrix metalloproteinase (MMP)-9 and TIMP-1 concentrations were measured by ELISA
Chen	2012	China	12 patients with COPD were recruited in the study, where 6 were in the clinical stable condition and 6 in the acute exacerbation stage. Six healthy people were also enrolled as normal controls. Three smokers and three non-smokers were included in each group. COPD was diagnosed on the basis of clinical evaluation and pulmonary function tests showing airflow obstruction, according to the GOLD criteria (FEV1 < 80% predicted, FEV1/FVC < 70% and bronchodilation effect < 12%)	Serum IL-1 F6, IL-17B R, IL-17D, IL-19, Lymphotoxin beta, MMP-10 measuring inflammatory factors: A Custom Raybio® Human Inflammation Antibody Array kit
Attaran	2010	Iran	Between April and September 2008, 50 patients with COPD were recruited in the study who attended the pulmonary clinic of Ghaem hospital, Mashhad, Iran, were entered into that cross-sectional study	Serum IL-6 was measured by the Bender MedSystem Human IL-6 (BMS 213/2; Medical System Diagnostic GmbH, Austria, test sensitivity 1.4 pg/ml)