CYTOKINE GENE-EXPRESSION IN PANCREATIC-ISLET GRAFTS IN THE RAT

We examined the production of cytokine message in allogeneic and synge neic rat pancreatic islet grafts using specific primers and polymerase chain reaction, Freshly isolated islet preparations contained transcr ipts for interleukin (IL)-1 alpha, IL-6, IL-10, and interferon-gamma ( IFN-gamma) but not for IL-2, IL-1 alpha in allogeneic grafts showed in creased and consistently high expression from 1 to 7 days after transp lantation, but the level in syngeneic grafts fell quickly to pretransp lant levels. IL-2 and IFN-gamma transcripts were found in allogeneic g rafts at 1, 3, 5, and 7 days after transplantation with a peak at day 5, but these cytokines were almost absent from syngeneic grafts, The p eak of IL-6 expression was 1 day after transplantation in both syngene ic and allogeneic grafts, and then the level fell quickly, IL-10 was p roduced at approximately the same high level at all time points in bot h syngeneic and allogeneic grafts, The results show that freshly isola ted islet preparations contain IL-1 alpha, IL-6, IL-10, and IFN-gamma transcripts at the time of transplantation. The initial production of cytokines in islet grafts, especially IL-1, may explain phenomena such as graft nonfunction, rapid rejection, and lack of response to immuno suppression.