Carvalho, SerafimSantos, MarleneLima, LuísMota-Pereira, JorgePimentel, PauloMaia, DulceCorreia, DianaGomes, SofiaCruz, AgostinhoMedeiros, Rui2017-01-202017-10-312016Carvalho, S., Santos, M., Lima, L., Mota-Pereira, J., Pimentel, P., Maia, D., Correia, D., Gomes, S., Cruz, A., & Medeiros, R. (2017). IL6-174G > C genetic polymorphism influences antidepressant treatment outcome. Nordic Journal of Psychiatry, 71(2), 158–162. https://doi.org/10.1080/08039488.2016.12426501502-4725http://hdl.handle.net/10400.22/9333Major depressive disorder is a condition associated with dysregulated cytokine levels; among these, IL6. Furthermore, genetic variations within cytokine genes have been proposed to predict antidepressant treatment outcome. This study aims to evaluate the role of IL6-174G > C and IL6R D358A A > C functional poly-morphisms in antidepressant treatment phenotypes, specifically remission, relapse, and treatment resistant depression (TRD). The referred polymorphisms were genotyped in 80 MDD patients followed at Hospital Magalh~aes Lemos, Portugal, within a period of 27 months. It was found that patients carrying IL6-174 GC genotype present a protection towards the development of TRD (OR ¼ 0.242; 95% CI ¼ 0.068–0.869; p ¼ .038), when compared with GG genotype. Additionally, carriers of IL6-174 CC genotype remit earlier than patients with IL6-174 GG/GC genotypes, with a median time to remission of 6 weeks for CC carriers and 15 weeks for GG or GC carriers (p ¼ .030, Log-rank test). No association was found between IL6R D358A genetic polymorphism and any of the treatment phenotypes evaluated. The IL6-174G > C polymorphism influences antidepressant treatment outcome in this sub-set of MDD patients, providing a putative mechanistic link for the dysregulated IL-6 levels described in the literature in patients with TRD.engIL6Genetic polymorphismsAntidepressantsTreatment resistant depressionjournal article10.1080/08039488.2016.1242650