Elevated IL-17 and TGF-β Serum Levels: A Positive Correlation between T-helper 17 Cell-Related Pro-Inflammatory Responses with Major Depressive Disorder.
BACKGROUND
Depression is a mental disorder that highly associated with immune system. Therefore, this study compares the serum concentrations of IL-21, IL-17, and transforming growth factor β (TGF-β) between patients with major depressive disorder and healthy controls.


METHODS
Blood samples were collected from 41 patients with major depressive disorder and 40 healthy age-matched controls with no history of malignancies or autoimmune disorders. The subjects were interviewed face to face according to DSM-IV diagnostic criteria. Depression score was measured using completed Beck Depression Inventory in both groups. The serum concentrations of IL-21, IL-17, and TGF-β were assessed using ELISA.


RESULTS
The mean score of Beck Depression score in the patient and control groups was 35.4±5.5 and 11.1±2.3. IL-17 serum concentrations in the patients and the control group were 10.03±0.6 and 7.6±0.6 pg/mL, respectively (P=0.0002). TGF-β level in the patients group was significantly higher than compare to the control group; 336.7±20.19 vs. 174.8±27.20 pg/mL, (P<0.0001). However, the level of IL-21 was not statistically different between the two groups 84.30±4.57 vs. 84.12±4.15 pg/mL (P>0.05).


CONCLUSIONS
Considering pro-inflammatory cytokines, current results support the association of inflammatory response and depressive disorder. So, it seems that pro-inflammatory factors profile can be used as indicator in following of depression progress and its treatment impacts.
Department of Immunology and Microbiology, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.
Mohammad Hasan
MH
Davami
Department of Immunology and Microbiology, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.
Rasoul
R
Baharlou
Department of Immunology and Microbiology, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.
Abbas
A
Ahmadi Vasmehjani
Department of Psychiatry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
Ahmad
A
Ghanizadeh
Department of Psychiatry, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.
Mitra
M
Keshtkar
Department of Student Research Committee, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.
Iman
I
Dezhkam
Department of Immunology and Microbiology, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.
Mohammad Reza
MR
Atashzar
Inflammatory response; Interleukin-17; Major depressive disorder; Transforming growth factor-beta; interleukin-21