Interleukin-1β (C-511T) Genetic Variant and Major Depressive Disorder: A Systematic Review

Major Depressive Disorder (MDD) has a multifactorial etiology and pathogenesis that significantly impacts an individual's quality of life. One of the possible correlations for its onset is the activation of inflammatory responses resulting in neurodegeneration and, consequently, the emergence of depressive symptoms. Interleukin-1β is a regulatory cytokine of the immune and nervous systems that acts on several processes, including mood regulation. This systematic review analyzed the IL1B (C-511T) (rs16944) variant's CC and CT genotype frequencies and their associations with MDD in different populations while also verifying the TT genotype's influence on response to antidepressant therapy. This review involved searching five databases, and articles were selected according to the PECOS inclusion criteria, resulting in eight articles. The findings highlight distinct clinical outcomes: the CC genotype was more frequently associated with greater MDD symptom severity, whereas the TT genotype was predominantly associated with antidepressant treatment response; thus, these associations should not be considered equivalent in terms of susceptibility to disease onset. However, despite these findings, other studies have found no significant association between this genetic variant and MDD. Therefore, further studies across different populations are needed to better understand the role of this polymorphism in the etiology of this disorder.