Localization of T and B lymphocytes in histologically normal adult human donor liver

Donor liver suitable for successful transplantation often has one or more of a range of mild abnormalities including inflammation. Passenger leukocytes documented in donor liver are thought to result from inflammatory stimuli in response to ischemic, drug or alcohol related damage. The aim was to identify donor livers, which were free of any evidence of damage, and to determine if, and where, leukocytes were present in these pristine livers.

Eight of eighteen donor livers, examined by hematoxylin and eosin staining, were found to be free of any evidence of pathological damage. Sections from these livers were stained with antibodies against CD3 (T cell marker), CD20 (B cell marker) and CD45 (common leukocyte antigen).

Each of these livers were found to have significant numbers of T lymphocytes, located mainly in the portal tracts but also scattered throughout the parenchyma. A similar distribution of B cells was detected but at much lower levels.

The presence of lymphocytes in the human liver is usually considered a hallmark of pathology. The demonstration of significant lymphocyte populations in pristine liver, particularly in the parenchyma, supports the hypothesis that the human liver harbors tissue-resident lymphocytes.