Lymphocyte Homing to the Liver

The liver has a large population of resident lymphocytes that survey the liver under normal conditions but can be rapidly expanded through recruitment and proliferation in response to various insults. The tissue-specific homing molecules for tissues such as intestine and skin are well characterized, but liver-specific homing molecules are still not known. The molecules that have been implicated in liver homing are also selectins, integrins, and chemokines, as in other tissues, however, the unique flow conditions, architecture, and specialized cell populations allow different molecules to play prominent roles in various microenvironments within the liver. In this review, we take a closer look at adhesion molecules (selectins, α4β7, α4β1, αLβ2, and vascular adhesion protein-1) and “inflammatory” chemokine receptors (CXCR3, CCR5, and CXCR6) under various inflammatory conditions and compartments within the liver. Their prominent roles in accumulating lymphocytes to inflamed liver suggest its importance as possible therapeutic targets for human liver diseases.