RÉSUMÉ
BACKGROUND: Involvement of the immune system is one of the issues raised in the pathophysiology of depression. BCL2 and BAX genes are related to immune system regulation. We investigated the BCL2 and BAX expression as a probable mechanism of immune system involvement in depression. MATERIALS AND METHODS: This case-control study was conducted on 28 patients with major depression (case) and 28 nondepressed individuals (control) within the age range of 18-55 years in the Isfahan University of Medical Sciences. Clinical interviews, based on the Diagnostic and Statistical Manual of Mental Disorders, were conducted to detect depression, and Beck's Depression Inventory was used to measure the severity of depression in the individuals. In addition, a real-time polymerase chain reaction was employed to compare the level of Bax and Bcl-2 gene expression in peripheral blood lymphocytes. The multivariate covariance analysis was used to explore the correlation between BCL2 and BAX gene expression and to control the effect of duration and severity of depression. RESULTS: The results showed that none of the variables including group membership, the duration of depression, and the severity of depression were not significantly correlated with the expression of BCL2 and BAX genes. Furthermore, there was no statistically significant relationship between the Bax and Bcl-2 genes expression in case and control groups (P > 0.05). CONCLUSION: Depression may have no impact on Bax and Bcl-2 gene expression in patients with major depression. Studies with larger sample size are recommended.