Chapter 19 - Intracellular Sensors and Cellular Metabolism in Allogeneic Hematopoietic Stem Cell Transplantation

Abstract

Living cells utilize several mechanisms to “sense” and “respond” to changes in external and internal environment that elicit or modulate inflammation and immunity. Immune responses are induced by moieties with certain molecular patterns from either endogenous or exogenous sources or through metabolic perturbation (Iwasaki and Medzhitov, 2010; Beutler, 2009; Akira et al., 2006) [1–3]. The inducers that are sensed and lead to a functional immune response have been variously characterized as “danger” or “damage” or “nonself” from promiscuous but biologically distinct molecular patterns (Medzhito, 2007) [4]. They include damaged tissues, chemicals, metabolites, non–self-antigens from microbes, and allogeneic tissues (Seong and Matzinger, 2004) [5]. In this chapter, the general biology and specific role of “sensors” and the perturbation of metabolic pathways in immune cells will be discussed, as well as their impact on allogeneic hematopoietic cell transplantation and graft versus host disease. The first part of the chapter is focused on the sensors while the second is on the metabolic alterations.