The spectrum of lymphoid subsets preferentially recruited into the liver reflects that of resident populations.

Intrahepatic lymphocytes (IHL) differ phenotypically from cells found in the peripheral blood or in lymphoid organs. The liver contains T-cells that are also found in lymphoid organs but a higher proportion of these T-cells compared to those in lymphoid organs express activation or memory markers and very few naïve T-cells are present within the liver. Furthermore, subsets such as NK and NK T-cells, which are detected at comparably lower levels within the lymphoid organs are increased within the liver. To investigate whether a preferential recruitment of certain lymphoid subsets from the circulation contributes to the composition of intrahepatic lymphocytes, we compared their frequency in the liver with their organ tropisms. CFSE-labeled murine lymphoid cells were injected intravenously and their distribution within liver and spleen was analyzed after 24 h. Especially CD45RB(low) memory T-cells, NK and NK T-cells, which are also present at high proportions within IHL, became predominantly recruited into the liver. In contrast, subsets such as naïve CD62L(high) T-cells and B-cells, which are predominantly represented within the lymphoid organs, preferentially migrated into the spleen. These findings indicate that the pattern of migratory preferences reflects the representation of various subsets within the intrahepatic lymphocytes surprisingly well, suggesting that the composition of intrahepatic lymphocytes is largely shaped by the dynamics of entry and exit of cells into the organ.