Predicting value of serum chemokine interleukin 8 for acute exacerbation of chronic obstructive pulmonary disease / 第二军医大学学报

ABSTRACT

Objective To explore the predictive value of serum chemokine interleukin (IL)-8 for acute exacerbation of chronic obstructive pulmonary disease (COPD). Methods A total of 112 COPD patients with acute exacerbation, who were initially diagnosed or did not receive standardized treatment in our hospital from Sep. 2015 to May 2016, were included in this study. According to serum level of IL-8, the patients were divided into high IL-8 group (<62 pg/mL) and low IL-8 group (≥62 pg/mL). The blood test results, serum levels of immunoglobulin E (IgE), IL-8, IL-6, tumor necrosis factor α (TNF-α), and superoxide dismutase (SOD), fractional exhaled nitric oxide (FeNO) and pulmonary function parameters were compared between the two groups. The interval time between beginning of follow-up and the first moderate to severe acute exacerbation and the times of acute exacerbation were recorded and compared between the two groups during one-year follow-up. Univariate analysis between serum IL-8 and variables was performed by Spearman correlation analysis. Cox regression was used to analyze the relative risk (RR) of acute exacerbation of the COPD patients in the two groups. Kaplan-Meier curve was used to analyze the proportion of the patients without acute exacerbation and hazard ratio (HR) during the follow-up in the two groups. Results The median levels of IL-8 were 170.00 (111.00, 472.00) pg/mL and 22.40 (7.90, 34.45) pg/mL in the high IL-8 group (n=47) and low IL-8 group (n=65), respectively. The proportion of allergic rhinitis cases and COPD assessment test (CAT) score were significantly higher in the high IL-8 group than those in the low IL-8 group (51.06% [24/47] vs 10.77% [7/65], P<0.01; 24.81±5.10 vs 19.38±4.27, P<0.01). The acute exacerbation times were significantly more in the high IL-8 group than those in the low IL-8 group (1.5 [1.0, 2.5] vs 1.0 [0.0, 1.5], P<0.01). Before inhaling bronchodilators, the high IL-8 group had significantly lower forced expiratory flow at 25%-75% of forced vital capacity (FEF25%-75%), FEF25%-75% as percentage of predicted, forced expiratory flow at 75% of forced vital capacity (FEF75%) and FEF75% as percentage of predicted versus the low IL-8 group ([0.73±0.55] L/min vs [1.26±1.15] L/min, [23.89±16.64]% vs [35.21±26.88]%, [0.32±0.19] L/min vs [0.57±0.53] L/min, and [25.32±13.27]% vs [39.97±29.42]%, all P<0.05). The serum IL-8 level was significantly negatively correlated with diffusion capacity for carbon monoxide as percentage of predicted (DLCO%Pred; r=-0.402 1, P=0.001 8), and the DLCO%Pred was significantly lower in the high IL-8 group than that in the low IL-8 group ([51.52±26.41]% vs [72.98±18.70]%, P=0.029). The cumulative risk of acute exacerbation was significantly higher in high IL-8 group than that in the low IL-8 group, with RR being 3.75 (95% confidence interval [CI] 1.200-11.716, P=0.029). The median interval time to the first acute exacerbation was significantly shorter in the high IL-8 group than that in the low IL-8 group (HR=3.066, 95% CI 1.053-8.927, P=0.039). Conclusion Serum IL-8 can be used as a predictive biomarker for acute exacerbation of COPD patients, which may involve allergic constitution, small airway function deterioration, and decreased diffuse capacity among these patients.