Josef F Fowler Taryn A Eubank Kevin W. W Garey ^*

• University of Houston, Houston, United States

Background. Proton pump inhibitors (PPIs) are one of the most used drugs worldwide.While generally considered safe, usage of PPIs is associated with several adverse outcomes including acute infectious diseases. PPIs influence macrophage and neutrophil function although a systematic review has never been undertaken. The purpose of this systematic review was to determine potential mechanisms that PPI inhibition of macrophage and neutrophil function may increase infection risk in susceptible hosts.Methods. A database search using SCOPUS and PubMed was performed to identify studies that investigated the effects of PPIs on neutrophils or macrophage function.Results. Final screening yielded 21 English-language research articles that focused on the impacts of PPIs on the function of macrophages and neutrophils. PPI mechanistic effects included cytotoxic effects on polymorphonuclear neutrophils, inhibition of reactive oxygen species (ROS) and reactive nitrogen species, phagocytosis and phagosomal degradation, inhibition of chemotaxis and migration, altering Toll-like receptor signaling and p38 protein phosphorylation in immune cells, and altering neutrophil and macrophage gene expression.Discussion. The impact of PPIs on MΦs and neutrophils regarding their role in the immune response to bacterial pathogens was summarized. PPI effects on macrophage and neutrophils occurred due to the therapeutic mechanism of PPIs, the protonation of a sulfhydryl groups and the subsequent formation of a disulfide bond, and other pleiotropic manners. Given the common use of PPIs these results highlight the necessity to optimize PPI use and stewardship to curtail unnecessary drug use.