Effects of perinatal SSRI therapy on immune serotonergic system 4755

Abstract Description Peripartum depression (PPD) is widely prevalent, affecting about 1 in 4 birthing people, and suicide is now the leading cause of postpartum death. Selective serotonin reuptake inhibitors (SSRIs) are the first-line treatment for PPD, yet their safety to use during pregnancy is debated. Depression is characterized by chronic inflammation and altered immune function, but how the unique immunological environment of pregnancy modulates these effects is unknown. Understanding how SSRI therapy modulates immune responses during pregnancy could improve risk assessments for complications like fetal rejection or heightened disease susceptibility. This study investigates how SSRIs impact the serotonergic system in immune cells and its relevance to clinical outcomes during pregnancy. Peripheral blood samples will be collected from pregnant individuals without PPD, with untreated PPD, and with SSRI-treated PPD during the first and third trimesters. High-dimensional mass cytometry will analyze immune cell populations and activity. We hypothesize that untreated PPD will present a pro-inflammatory immune profile with elevated pro-inflammatory cytokines, reduced regulatory T cells, and increased proportions Th1 and Th17 cells. In contrast, SSRI treatment is expected to alleviate this inflammation, returning immune cell populations and activity to levels seen in healthy controls. These findings will provide insights into the immune-related risks and benefits of SSRI therapy during pregnancy. Topic Categories Neuroimmunology (NEUR)