Application Of Immune Cell Functional Assay In Monitoring Immune Status In Renal Transplant Recipients

Background As the best renal replacement therapy for patients with chronic renal failure, renal transplantation has been carried out over half a century. Though transplantation technology has been basically overcome, the rejection after transplantation remains not only the biggest issue of transplant physicians and patients, but also main obstacle of long-term graft survival. Successful management of the transplant recipient currently required lifelong immunosuppression to avoid graft rejection. While graft survival has been dramatically improved, the patient was at increased risk of drug toxicity, opportunistic infections and cancer. In addition, basal immune reactivity to therapy, surgical trauma, anesthesia, and pharmacokinetic differences on drug metabolism had all been demonstrated to influence immunity, so it is necessary to monitor immune status of kidney transplant recipients. In order to accomplish proper immunosuppressant regimen and the balance between immunosuppression insufficiency and overdose, it becomes an important issue in transplant clinical work to assess the globe immune status of kidney transplant recipients. At present, Cylex ImmuKnow is the only assay approved by FDA to test cell mediated immunity of transplant recipients receiving immunosuppression therapy. It reflects cell mediated immunity directly and targets for immunosuppresion medication. The results can be obtained in 24 hours. Furthermore, the results can be quantified. So it is the promising for monitoring immune status and medication instruction. However, as a new immunology evaluation parameter, ImmuKnow still need to be validated and improved in wider extent and bigger sample size. It should be validated whether this assay fits Chinese nationality heredity backgrounds. Object To monitor dynamic immune status fluctuation in renal transplant recipients by using immune cell functional assay (ImmuKnow CD4+ T cell ATP assay); to analyze the correlation between immune cell function and acute rejection, acute kidney injury or rejection after transplantation; to evaluate the value of immune cell functional assay in monitoring immune status in renal recipients.Methods 20 apparent healthy Chinese and 131 adult renal transplant recipients who received transplantation in the First Affiliated Hospital of Zhejiang University during March 2010 to November 2010 were under investigation. The research also included renal recipients who suffered from rejection or infection during that time. Samples were divided into the following groups:health control group (HC), pretransplant group (Pre-Tx), stable group (Tx), infection group (infection), acute rejection group (AR), acute kidney injury group (AKI). Tx, AR and AKI group were biopsy verified, infection group was verified by chest X-ray examination or pathogenic test.2ml whole blood sample with sodium heparin anticoagulated vacutainer tubes was drawn from healthy adults and transplant patients (0d,2w, 1m,3m,6m and during infection or rejection) for ImmuKnow CD4+ T cell ATP assay. Simultaneously,2ml whole blood was drawn for lymphocyte subset assay (CD4/CD8), lml for testing blood Fk506 level,5ml for mixed lymphocytes reaction. The data was analyzed by SPSS 16.0. The mata analysis included T test, One-Way ANONA, Hochberg's GT2 and Logistic regression analysis.Results The ATP concentration of HC group was 401±153ng/ml and recipients before transplantation was 405±161 ng/ml, the median of Pre-Tx group was significantly lower than HC group (317 ng/ml to 404 ng/ml). The immune status of recipients reflecting by ImmuKnow ATP fluctuated after kidney transplantation. The ATP concentration during the first month after operation (603±176 ng/ml) was higher than that in 3 months (424±191) and 6 months (396±175) after transplantation. The immune status decreased to normal level at 6 months after transplantation. ATP concentration of AR group (539±217 ng/ml) and that of the other three groups (Tx group 332±155 ng/ml, Infection group 288±140 ng/ml, AKI group 336±125 ng/ml) were analyzed by One-Way ANONA Hochberg's GT2. ATP concentration of AR group was significantly higher than all other three groups P<(0.05). Correlation analysis was performed on the ATP concentration of recipients and MLR, CD4/CD8, Fk506 blood level respectively. The correlation coefficient was R2=0.0072 (n=128), R2=2E-06 (n=190), R2=0.004 (n=184) respectively.Conclusion 1. We use the new method of monitoring immune status, immune cell functional assay (ImmuKnow CD4+ T cell ATP assay) to investigate the dynamic immune status change in kidney transplant recipients. During the first month after transplantation, recipients'immune status was relatively strongger and at six months after transplantation it decreased to the level pretranlplantation.2. The ImmuKnow ATP concentration of recipients was in a rising trend when acute rejection occurred. ImmuKnow assay has a high predictive value 3. ImmuKnow ATP concentration was not correlated with CD4/CD8,MLR or Fk506 blood level.