2016 ACVIM Forum Research Abstract Program

This study describes for the first time an association between an increased subpopulation of PMNs, namely the LDGs, and an inflammatory disease in horses. LDGs appear to be mostly constituted of mature cells in both healthy and heaves-affected horses. The significance of these findings remains to be ascertained. Equine Protozoal Myeloencephalitis (EPM) is arguably the most common and costly equine neurologic diseases in the United States. The national seroprevalence is >50%, but only 0.5-1% of all horses develops disease during their lifetimes. Some EPM affected horses have decreased immune responses. A cell-mediated immune response appears to be protective for development of EPM after infection with S. neurona in mouse models. Therefore, in addition to specific anti-protozoal medications, levamisole has been proposed as an adjunctive therapy to upregulate the immune response in EPM affected horses. Studies have been performed in other species to address whether levamisole alters immune function in vitro or in vivo, but there are very limited studies in equids. We hypothesized that We hypothesized that levamisole can upregulate a cell mediated macrophage (M1) dendritic cell (DC1) CD4 Thelper 1 (Th1) CD8 Tc1 immune response in vitro.