This study examined differences in cytokine gene expression in the peripheral blood lymphocytes of healthy never smokers and healthy smokers in response to lipopolysaccharide (LPS), an immune trigger, and dexamethasone (DEX), an immune suppressor. Blood was drawn from 48 healthy adults and lymphocytes were exposed to LPS, DEX, or both. Gene expression was analyzed and it was found that DEX significantly reduced the expression of pro-inflammatory cytokines IL-6, TNF-α, and IFN-γ in response to LPS, and this immunosuppressive effect was greater in never smokers than smokers for TNF-α and IFN-γ.