Depression is a highly prevalent comorbidity in patients suffering from chronic obstructive pulmonary disease (COPD). Both, depression and COPD are believed to be associated with inflammation. The aim of our study was to verify hypothesis that altered inflammatory response causes depression in patients with chronic obstructive pulmonary disease.

Blood was collected from 45 patients of whom 18 had COPD, 18 were depressed and 9 had COPD with comorbid depression. Total of 27 age and sex matched healthy controls were also included in the study. IL-2, IL-8 and IL-17A concentrations were assayed by ELISA technique in sera of all subjects.

We observed significantly decreased concentration of IL-17A in a group of depressed patients (D) when compared with controls, 4.46 ± 0.573 pg/mL vs. 8.87 ± 1.182 pg/mL, respectively, P = 0.0005. Increased concentration of IL-2 in depressed patients (D) as compared with controls, 3.00 ± 0.223 pg/mL vs. 2.30 ± 0.176 pg/mL, respectively, P = 0.013 was also revealed. There was also increased concentration of IL-8 in COPD subjects if compared with controls and depression group, 4.55 ± 0.176 pg/mL vs. 3.71 ± .132 and 3.95 ± 0.118 pg/mL, respectively, P = 0.008.

The results from our study suggest that there is significant difference between depression and COPDs with respect to IL-8 concentration also a lower concentration of IL-17A was noticeable in depressed patients (P = 0.06). We need more data on depressed COPD patients to argue the role of inflammation on depression in COPD patients.