556 Maternal Opioid Use Leads to Aberrant Maternal and Fetal Immunity

Abstract

OBJECTIVES/GOALS: Maternal opioid use disorder (OUD) is linked to poor fetal outcomes. While it has been established that opioids can cross from maternal to fetal circulation, the mechanisms underlying these adverse outcomes remain poorly defined. This study aims to uncover OUD-associated immunological changes in maternal and fetal circulation. METHODS/STUDY POPULATION: To study the effect of maternal OUD on the maternal immune system at delivery, we collected maternal blood samples at delivery from healthy pregnant women (controls) and pregnant women with a diagnosis of severe OUD. To study the impact of maternal OUD on newborn immunity, we also collected umbilical cord blood (UCB) at delivery. Flow cytometry was used to determine the frequency and phenotype of circulating immune cell subsets and responses to stimulation. Isolated monocytes were stimulated with bacterial/viral agonist cocktails, while T and NK cells were stimulated with PMA/ionomycin. The impact of maternal OUD on circulating immune mediators was determined by Luminex and on monocyte activation markers sCD14 and CRP by ELISA. RESULTS/ANTICIPATED RESULTS: In maternal circulation, OUD was associated with a significant decrease in markers of inflammation, cell proliferation, and activation. Frequencies of immune cell subsets were impacted by OUD, shown by an expansion of CD8+ EMRA T cells, marginal-zone B cells, mDCs, non-classical monocytes, and CD16low NK cells. While no differences were seen in T and NK cell responses to stimulation, monocytes and pDCs had significantly lower responses to bacterial and viral agonist stimulation. Analysis of UCB revealed increased levels of pro-apoptotic/T cell exhaustion mediators and pro-inflammatory cytokines, albeit decreased levels of several chemokines and growth factors. The UCB immune landscape is altered with maternal OUD, as demonstrated by a shift from naive to memory CD8+ T cells and a decrease in pDC frequency. DISCUSSION/SIGNIFICANCE: OUD dampens maternal peripheral immunity, possibly contributing to poor placental function or premature/delayed labor. Monocytes and pDCs lack antimicrobial functionality, suggesting increased infection susceptibility with OUD. Finally, these implications extend to the fetal compartment, shown by heightened immune activation in UCB.