Background: Chronic obstructive pulmonary disease (COPD) is a major noncommunicable respiratory disease with diverse pulmonary and external pulmonary clinical manifestations. This disease is one of the leading causes of mortality in the world, and about 1% of the adult population suffers from COPD. Objectives: The aim of this study was to assess the effect of Montelukast on the serum level of inflammatory factors in patients with chronic obstructive pulmonary disease (COPD). Methods: In a randomized placebo-controlled trial, 74 patients with COPD with stable conditions were followed for two months after a random assignment to the placebo and montelukast (10 mg/d) groups. All patients continued their treatment protocol irrespective of their group to evaluate the effects of the addition of montelukast on serum levels of common inflammatory factors, such as Tumor Necrosis Factor alpha (TNF-α), C-reactive protein (CRP), and Interleukin 18 (IL-18) in COPD patients. SPSS 18 software was used for data analysis. Results of quantitative data were reported as mean ± standard deviation or median (interquartile range) and qualitative data as frequency (percentage). If the data distribution was normal, the paired t-test was used to compare the mean before and after and using an independent t-test to compare the mean changes between the two groups. The Mann-Whitney U test and Wilcoxon signed-rank test were also used if the data were not assumed to be normal. A P < 0.05 was considered as the level of significance. Results: At baseline, there were no significant differences in laboratory studies between the two groups. After two months of intervention, there was no evidence of decreased TNF-α and CRP in the montelukast group. IL-18 levels were not significantly different at the end of the study between the two groups (P = 0.23), but it had a decreasing trend in the montelukast group (from 20.25 ± 5.98 ng/ml to 16.19 ± 4.17 ng/ml, P < 0.001). Conclusions: Montelukast complementary therapy in COPD patients only improve the serum IL-18 levels and has not a reducing effect on the level of TNF-α and CRP evidenced by keeping their trend from baseline to the end of the study.

Objective Smoking is one significant global health care problems, that not only affects the users but also endangers the health of people inhaling the smoke (passive smoking/secondhand smoke). The serum level of IL-18, an important regulator of inherent and acquired immune response, is affected by cigarette smoking. The aim of this study was to evaluate the effect of secondhand smoke (SHS) exposure on IL-18 serum level in non-smoker adults. Methods In a case-control study, using easy sampling method, 76 non-smokers who were exposed to cigarette smoke for at least 1 h daily during the past year were considered as exposure group, while 76 of their companions without exposure to cigarette smoke (after matching age) were considered as non-exposure group. Serum IL-18 levels were measured for all participants and finally compared between the two groups using Chi-square test. P value < 0.05 was considered to be statistically significant. Results The exposure and non-exposure groups included 58 (76.3%) and 25 (32.9%) males, respectively ( P < 0.001). The mean ± SD of age for the exposure and non-exposure groups was 35.42 ± 10.37 and 38.47 ± 12.49 years, respectively ( P = 0.102). There was no significant difference between the mean serum levels of IL-18 in the exposure (54.81 ± 57.03 ng/ml) and non-exposure (41.49 ± 42.14 ng/ml) groups ( P = 0.104). Conclusion The exposure to secondhand smoke has no significant effect on serum level of IL-18 in exposed adult individuals. However, more studies with larger sample sizes on different populations are required to confirm these results.