Abstract
ISG-15 gene is affected directly by IFN-alpha which the later used widely as a therapy for several diseases. Studies showed MDD can be developed after IFN-alpha treatments which can affect patient's normal life style. This study aims to investigate polymorphism in ISG-15 gene in MDD patients compared to healthy volunteers Peripheral blood mononuclear cells (PBMCs) were collected from 200 volunteers. About 100 patients diagnosed with MDD and 100 healthy individuals used as control. DNA was extracted, and ISG-15 polymorphism was evaluated. Serum ISG-15 levels were evaluated between Healthy and MDD patients by ELISA. Levels of serum ISG-15 were significantly higher in MDD patients (P<0.0001). Homozygous genotype was higher in MDD patients compared with healthy control (P<0.031) and serum ISG-15 levels were higher as well than healthy control. In addition, allele (a) polymorphism is more frequent in MDD patients compared to healthy control (P<0.025). Our results found that serum ISG-15 levels are higher in MDD than healthy control. Homozygous genotype was higher in MDD patients compared with healthy control. Polymorphism in ISG-15 gene can be a risk factor in MDD patients.