ACTIVATED SUBPOPULATIONS OF LYMPHOCYTES AND NATURAL-KILLER-CELLS IN NORMAL LIVER AND LIVER GRAFTS BEFORE TRANSPLANTATION

Aims/Background: The anatomic structure of the liver suggests that it is a place of intense trafficking between intra-hepatic and peripheral blood compartment leukocytes. Furthermore, the liver contains a large number of passenger leukocytes that may play a role in the appearance of donor-type microchimerism after transplantation. In this study, we aimed to define the principal lymphocyte sub-populations contained in donor peripheral blood and liver grafts and in normal liver removed d uring minimally invasive surgery. Methods. Liver biopsies were taken a t the time of vascular clampage during liver extraction from donors in a brain dead state (GI: n=14). Normal liver biopsies were removed dur ing minimaly invasive surgery (GII: n=10). Results: We observed eviden ce of the presence of lymphocytic activation associated with the two m ajor CD8(+) lymphocyte and natural killer (NK) cell populations in the two groups, with a significant increase in TCR gamma delta-bearing ly mphocyte receptors between normal liver and the liver graft. Conclusio ns: The presence of activated leukocytes in the graft could have a fun damental role in induction of peripheral tolerance. This activation co uld be the result of a basic immunological response linked to the inte raction of T cells and NK cells, and of secondary activation due to st ress and the conditions necessary for organ removal from donors in a b rain dead state.