Interleukin-6 and airflow limitation in chemical warfare patients with chronic obstructive pulmonary disease

Davood Attaran¹, Shahrzad M Lari¹, Mohammad Towhidi¹, Hassan Ghobadi Marallu², Hossein Ayatollahi¹, Mohammad Khajehdaluee¹, Mostafa Ghanei³, Reza Basiri^1
1Lung Disease and Tuberculosis Research Center, Mashhad University of Medical Science, ²Ardabil University of Medical Sciences, ³Research Center of Chemical Injuries, Baqiyatallah University of Medical Sciences, Tehran, Iran

Objectives: Chronic obstructive pulmonary disease (COPD) is one of the main late complications of sulfur mustard poisoning. The aim of this study was to evaluate serum levels of interleukin (IL)-6 in war veterans with pulmonary complications of sulfur mustard poisoning and their correlation with severity of airways disease.
Methods: Fifty consecutive patients with sulfur mustard poisoning and stable COPD, and of mean age 46.3 ± 9.18 years were enrolled in this study. Thirty healthy men were selected as controls and matched to cases by age and body mass index. Spirometry, arterial blood gas, six-minute walk test, BODE (body mass index, obstruction, dyspnea, and exercise capacity), and St George’s Respiratory Questionnaire about quality of life were evaluated. Serum IL-6 was measured in both patient and control groups.
Results: Fifty-four percent of patients had moderate COPD. Mean serum IL-6 levels were 15.01 ± standard deviation (SD) 0.61 pg/dL and 4.59 ± 3.40 pg/dL in the case and control groups, respectively (P = 0.03). There was a significant correlation between IL-6 levels and Global Initiative for Chronic Obstructive Lung Disease stage (r = 0.25, P = 0.04) and between IL-6 and BODE index (r = 0.38, P = 0.01). There was also a significant negative correlation between serum IL-6 and forced expiratory volume in one second (FEV₁, r = -0.36, P = 0.016).
Conclusion: Our findings suggest that serum IL-6 is increased in patients with sulfur mustard poisoning and COPD, and may have a direct association with airflow limitation.

Keywords: sulfur mustard, chronic obstructive pulmonary disease, interleukin-6, inflammation, chemical warfare