466 The Combination of Left Ventricular Torsion and Global Strain Based on Two-Dimensional Speckle Tracking Echocardiography Could Detect Treatment-Requiring Rejection in Heart Transplant Recipients

detecting risk of rejection in cardiac transplant recipients. Clinical factors, other than cellular rejection, may be reflected in the results of this testing. A better understanding of these clinical factors is important in interpreting test results. We hypothesized that pre-transplant panel reactive antibody testing and racial mismatch between donor and recipient could affect GEP results. Methods and Materials: We studied 140 GEP test results performed in 52 post-cardiac transplant recipients at our center. Peripheral blood mononuclear cells were isolated and processed. Samples were subjected to Allomap® GEP testing. Some patients had a single test, and others had up to 9 tests performed at various time points. Results: The GEP test scores were evaluated using univariate and multivariate modeling. Since transplant rejection grade is known to increase GEP score, the data were stratified based on rejection grade. Current prednisone dose emerged as an independent predictor of the GEP score, consistent with previously published data. Intravenous or oral pulse steroid dosing within the previous 30 days also emerged as an independent predictor. Quantitative panel reactive antibody testing (p 0.05) and racial mismatch between the donor and recipient (p 0.05) were independent predictors of the GEP score. The age of the donor, the age of recipient, gender-mismatch between donor and recipient, and the use of cyclosporine-based immunosuppression versus tacrolimus-based immunosuppression were not independent predictors of GEP score. Conclusions: These data suggest that clinical factors affect immune activation, particularly pre-transplant panel reactive antibodies and donorrecipient differences. Furthermore, the data suggest that these effects persist on current immunosuppressant regimens and influence GEP test results. These clinical parameters should be taken into account when interpreting results of GEP testing.