Impact of AUD on T Cells Effects on T-Cell Numbers, Phenotype, and Activation

Impact of Alcohol Abuse on the Adaptive Immune System| 185 In the United States, alcohol use disorder (AUD) is the third-leading cause of preventable death. It is associated with increased susceptibility to bacterial pneumonia; viral infections, such as HIV and hepatitis C virus (HCV); and increased postoperative morbidity and mortality. This increased susceptibility is mediated in part by functional alterations in various cells of the immune system. The immune system is broadly divided into two branches: innate and adaptive immunity. The innate immune system represents the first line of host defense and is necessary for inducing the adaptive immune response. The adaptive immune system can be subdivided further into cellular and humoral immunity. The main components of cellular immunity are CD4 and CD8 T cells. CD4 T cells play a critical role in the activation and differentiation of macrophages, CD8 T cells, and B cells. CD8 T cells, on the other hand, are essential for eliminating cells infected with intracellular pathogens, as well as cancer cells. Humoral immunity is mediated by B cells, which produce antibodies to eliminate extracellular microorganisms and prevent spread of infections. This review will summarize the impact of chronic heavy drinking or AUD as well as of moderate alcohol consumption on adaptive immunity and discuss future areas of research in this rapidly evolving field.