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Genetics

Genetic Markers of Acute Pancreas Allograft Rejection

Acute rejection remains a major problem for pancreas transplant recipients and accounts for 30 percent of graft failures in the first year after transplantation, in spite of improved surgical techniques and advances in immuno suppression. There are no universally accepted clinical indicators of rejection for pancreas allografts. Biopsy proven rejection is the standard for diagnosis; however, pancreas biopsies may be technically difficult to perform and associated with risks to the recipient.

Recently, increased cytotoxic lymphocytic expression of perforin, granzyme B, and Fas ligand in peripheral blood lymphocytes (PBL) has been associated with renal allograft rejection and may be indicative of subclinical acute rejection. Because of the increased incidence of acute rejection and the difficulty in establishing a clinical diagnosis, a similar technique to evaluate early markers of acute rejection is uniquely important in pancreas transplantation. We hypothesize that by measuring expression levels of 3 genes, perform, granzyme B, and Fas ligand, using a newly developed molecular technique (real-time reverse transcriptase polymerase chain reaction [RT-PCR]), we can noninvasively detect acute allograft rejection at the time or prior to development of biopsy proven rejection. The ultimate goal is to develop a reliable, non-invasive method to detect acute rejection, thus allowing for earlier therapeutic intervention and better outcomes in solitary pancreas recipients.

Long-term, we aim to expand the use of this technology to identify other genetic markers for acute rejection and develop microarray chip technology to clinically monitor the immunological status of transplant recipients. Methodology: Over a 2-year period, 25 solitary pancreas transplant recipients will be entered into the study. At least 40 milliliters of blood will be obtained pretransplant and at time of surveillance biopsies or clinic visits (10 time points). Peripheral blood lymphocytes (PBL) will be separated for mRNA extraction.

State-of-the-art real-time RT-PCR (ABI PRISM 7700) will be used to quantify gene expression levels of perforin, granzyme B, and Fas ligand. T-tests will be used to examine differences in gene expression levels between those patients with and without biopsy proven acute reiection.