Sinusoidal cells and liver immunology

Abstract

The liver is an organ with many facets, facilitating numerous physiological functions. This chapter concentrates on the role of the liver as an immune organ, with a special focus on the unique role of each cell type that builds the liver. The hepatic sinusoids are the interface between the blood (and thereby the rest of the body) and hepatocytes, and host several cell types intimately involved in immune processes. These cell types include “classical” immune cells such as Kupffer cells (resident liver macrophages), lymphocytes and dendritic cells, but also other sinusoidal cell types with key immune regulatory roles such as liver sinusoidal endothelial cells (LSEC) and hepatic stellate cells. Moreover, hepatocytes, though not sinusoidal per se, are also able to interact directly (via their abluminal villi) with circulating leucocytes through LSEC fenestrations thereby also influencing and responding to the liver sinusoidal immune environment. The purpose of this book chapter is to outline the role of all the above mentioned cells in the immunological milieu and discuss the implications of each cell type in human physiology.