Immune-endocrine interactions of the hypothalamus-pituitary-thyroid axis: integration, communication and homeostasis.

The immune and neuroendocrine systems are two essential physiological components of mammalian organisms. Although each is primarily committed to a set of tasks involved, on the one hand, in the protection from infection and disease, and on the other hand, in the regulation of metabolism and other physiological activities, there is also evidence indicating that active and dynamic collaborations exist between those systems in the execution of their designated functions. These interactions occur at many stages of embryonic and neonatal development, and they are a continual part of the normal homeostatic balance needed to maintain health. The present review discusses various historical and contemporary perspectives of immune-endocrine interactions involving the hypothalamus-pituitary-thyroid axis, and offers a hypothesis of how this aspect of the neuroendocrine system participates directly in the immune response to antigenic challenge, infection and disease.