Methamphetamine Administration Targets Multiple Immune Subsets and Induces Phenotypic Alterations Suggestive of Immunosuppression

Methamphetamine (Meth) is a widely abused stimulant and its users are at increased risk for multiple infectious diseases. To determine the impact of meth on the immune system, we utilized a murine model that simulates the process of meth consumption in a typical addict. Our phenotypic analysis of leukocytes from this dose escalation model revealed that meth affected key immune subsets. Meth administration led to a decrease in abundance of natural killer (NK) cells and the remaining NK cells possessed a phenotype suggesting reduced responsiveness. Dendritic cells (DCs) and Gr-1^high monocytes/macrophages were also decreased in abundance while Gr-1^low monocytes/macrophages appear to show signs of perturbation. CD4 and CD8 T cell subsets were affected by methamphetamine, both showing a reduction in antigen-experienced subsets. CD4 T cells also exhibited signs of activation, with increased expression of CD150 on CD226-expressing cells and an expansion of KLRG1⁺, FoxP3⁻ cells. These results exhibit that meth has the ability to disrupt immune homeostasis and impact key subsets of leukocytes which may leave users more vulnerable to pathogens.