Studies evaluating the effects of methamphetamine in animal models have shown that it can have negative impacts on the immune system (Harms, , 2012; Prakash et al., 2017; Salamanca, , 2015). Methamphetamine has been shown to inhibit processes of the innate immune system, including phagocytosis and antigen presentation. In phagocytosis, immune cells called phagocytes remove pathogens by ingesting them.‡ In antigen presentation, immune cells called macrophages “show” pathogen fragments to other immune cells to trigger a targeted response (Salamanca et al., 2015). More broadly, methamphetamine reduces the number of several important cells in the immune system, including dendritic cells, natural killer cells, monocytes and macrophages (Harms et al., 2012; Martinez, Mihu, Gácser, Santambrogio, & Nosanchuk, 2009; Prakash et al., 2017; Salamanca et al., 2015; Saito et al., 2008; Tallóczy et al., 2008).
Methamphetamine also affects the adaptive immune system. It alters the production of antibodies and reduces the ability of highly specialized cells, known as lymphocyte T-cells, to fight off pathogens.