Pancreatic passenger leukocytes in organs obtained from cadaver donors for allotransplantation

In previous studies we have demonstrated that human normal pancreata were populated by interstitial mononuclear cells constituted by dendritic cells (70%), macrophages (30%) and few B cells (less than 1%). Furthermore, the endocrine parenchyma and the centroacinar cells appeared negative for the detection of HLA-A,B,C molecules. In the present report, 15 pancreata from cadaver donors were studied by means of immunohistochemical methods. 5 out of 15 organs were found to contain a larger amount of interstitial hematic cells that were constituted mainly by macrophages and B cells, together with a small percentage of granulocytes and T cells. In such "infiltrated" pancreata both endocrine parenchyma and centroacinar cells displayed a positivity for HLA-A,B,C antigens. As HLA-class I antigens have importance in allo-recognition and rejection responses, our data suggest that pre-transplant biopsies may be useful for a better evaluation of the pancreatic tissue immunogenicity.