Chemokine Receptors CCR1, CCR3, CCR7 and Chemokines CX3CL1 and CCL5 are Significantly Up-Regulated and Very Reliable for Acute Rejection Diagnosis of Kidney Transplants

Background: The allo-immune response following organ transplantation constitutes one of the main determinants concerning both short- and long- term outcomes in renal graft recipients. Chemokines and their receptors play a diversified and important role, either homeostatic or inflammatory and direct different immune-competent cell types to the allograft. While deeply studied in the last two decades, controversy persists as a result of chemokines’ pleiotropic actions. We report our analysis of CCR1, CCR3, CCR7, CCL5 and CX3CL1 expression or synthesis by graft-infiltrating cells in human kidney transplants (KTx). At the same time, we tested their robustness in diagnosing acute rejection. Methods: Fine-needle aspiration biopsies (Fnab) were performed either on days 7 or 14 post-transplantation among stable KTx and on the day of acute rejection (AR) diagnosis. Fnab cytopreparations were studied by the enzymatic avidin-biotin complex staining for CCR1, CCR3, CCR7 and CX3CL1. From another subgroup of cases, Fnab samples were cultured for 48 hours and the supernatants were analysed for CCL5 by ELISA. Results: The group of AR cases showed a significantly up-regulated expression of CCR1, CCR3, CCR7 and CX3CL1 and a significantly higher synthesis of CCL5. The positive predictive values were respectively 92%, 97%, 85%, 76% and 78% and negative predictive values were by the same order, 100%, 73%, 100%, 98% and 83%. Conclusions: Our study permits us to advance that CCR1 and CCR3 play a significant and non-redundant role in acute rejection, and it is the first report of CCR3 association with rejection, probably related to CCL5. The presence inside the graft of significant up-regulation for CCR7 surmises that part of antigen presentation may be performed there without being restricted to secondary lymphoid sites. Our results with CX3CL1 confirm other reports.

Screening microRNA expression profile in patients with acute T cell mediated rejection after kidney transplantation

Objective:To explore the expression profile of miRNA in peripheral blood of patients with acute T cell mediated rejection after kidney transplantation.Method:4 patients with acute T cell mediated rejection(TCMR)after kidney transplantation were collected as experimental group.Meanwhile,4 patients under stable condition after kidney transplantation were collected as control group.The elbow blood was taken from two groups.The next generation sequencing was used to study miRNA libraries.Then,they were analyzed of variance by R language software.Results:14 miRNAs were differently expressed in the experimental group and control group,including 5 up-regulated miRNAs(P<0.05)and 9 down-regulated miRNAs(P<0.05).Conclusions:Peripheral blood miRNAs expression variations might be ideal biomarkers and reveal mechanisms for acute TCMR.

Predicting outcomes after kidney transplantation: Can Pareto’s rules help us to do so?

Kidney transplantation is the best option for kidney replacement therapy,even considering that most of the times the grafts do not survive as long as their recipients.In the Khalil et al's experience,published in this issue of the Journal,they analyze their second kidney graft survival and describe those significant predictors of early loss.This editorial comments on the results and put in perspective that most of the times,long-term graft survival could be inadvertently jeopardized if the immunosuppressive therapy is reduced or withdrawn for any reason,and that it could happen frequently if the transplant physician intends to innovate with the clinical care without proper evidence-based data.

Histopathological analysis of infiltrating T cell subsets in acute T cell-mediated rejection in the kidney transplant

AIM To compare the differential immune T cell subset com-position in patients with acute T cell-mediated rejection in the kidney transplant with subset composition in the absence of rejection, and to explore the association of their respective immune profiles with kidney transplant outcomes.METHODS A pilot cross-sectional histopathological analysis of the immune infiltrate was performed using immunohistochemistry in a cohort of 14 patients with acute T cellmediated rejection in the kidney transplant and 7 kidney transplant patients with no rejection subjected to biopsy to investigate acute kidney transplant dysfunction. All patients were recruited consecutively from 2012 to 2014 at the Singapore General Hospital. Association of the immune infiltrates with kidney transplant outcomes at up to 54 mo of follow up was also explored prospectively.RESULTS In a comparison to the absence of rejection, acute T cell-mediated rejection in the kidney transplant was characterised by numerical dominance of cytotoxic T lymphocytes over Foxp3^+ regulatory T cells, but did not reach statistical significance owing to the small sample size in our pilot study. There was no obvious difference in absolute numbers of infiltrating cytotoxic T lymphocytes, Foxp3^+ regulatory T cells and Th17 cells between the two patient groups when quantified separately. Our exploratory analysis on associations of T cell subset quantifications with kidney transplant outcomes revealed that the degree of Th17 cell infiltration was significantly associated with shorter time to doubling of creatinine and shorter time to transplant loss.CONCLUSION Although this was a small pilot study, results support our suspicion that in kidney transplant patients the immune balance in acute T cell-mediated rejection is tilted towards the pro-rejection forces and prompt larger and more sophisticated studies.

Relationship of Transforming Growth Factor-β1 and Arginase-1 Levels with Long-term Survival after Kidney Transplantation

In this study, we compared the serum levels of transforming growth factor-β1 （TGF-β1）, interleukin-10 （IL-10）, and arginase-1 in long-term survival kidney transplant recipients （LTSKTRs） with those in short-term survival kidney transplant recipients （STSKTRs）. We then evaluated the relationship between these levels and graft function. Blood samples were collected from 50 adult LTSKTRs and 20 STSKTRs （graft survival approximately 1-3 years post-transplantation）. All patients had stable kidney function. The samples were collected at our institution during the patients＇ follow-up examinations between March 2017 and September 2017. The plasma levels of TGF-β1, IL- 10, and arginase- 1 were analyzed using enzyme-linked immunosorbent assays （ELISA）. The levels of TGF-β1 and arginase-1 were significantly higher in the LTSKTRs than in the STSKTRs. The time elapsed since transplantation was positively correlated with the levels of TGF-β1 and arginase-1 in the LTSKTRs. The estimated glomerular filtration rate was positively correlated with the TGF-β1 level, and the serum creatinine level was negatively correlated with the TGF-β1 level. Higher serum levels of TGF-β1 and arginase-1 were found in LTSKTRs than in STSKTRs, and we found that TGF-β1 was positively correlated with long-term graft survival and function. Additionally, TGF-β1 and arginase-1 levels were positively correlated with the time elapsed since transplantation. On the basis of these findings, TGF-β1 and arginase- 1 may play important roles in determining long-term graft survival. Thus, we propose that TGF-β1 and arginase-1 may potentially be used as predictive markers for evaluating long-term graft survival.

Pre-and intraoperative predictors of acute kidney injury after liver transplantation

BACKGROUND Acute kidney injury(AKI)after liver transplantation(LT)is a frequent and multifactorial event related to increased morbidity and mortality.Risk factors for AKI after LT still need to be clarified.AIM To identify the predictors of acute kidney injury after liver transplantation.METHODS The frequency and pre-and intraoperative predictors of AKI within the first 7 d after LT were evaluated in adult liver transplant candidates in a single LT center in Croatia.AKI was defined according to the Kidney Disease:Improving Global Outcomes criteria.RESULTS Out of 205 patients(mean age 57±10 years;73.7%males,52.7%with alcoholrelated liver disease)93(45.36%)developed AKI,and the majority of them(58.06%)had stage 1.Only 5.38%of patients required renal replacement therapy after LT.The majority of patients(82.8%)developed AKI within the first two days after the procedure.Multivariate logistic regression identified pre-LT body mass index(OR=1.1,95%CI:1.05-1.24)and red blood cell transfusion(OR=1.66,95%CI:1.09-2.53)as independent predictors of early post-LT AKI occurrence.30-d survival after LT was significantly better for patients without AKI(P=0.01).CONCLUSION Early AKI after LT is a frequent event that negatively impacts short-term survival.The pathogenesis of AKI is multifactorial,but pre-LT BMI and intraoperative volume shifts are major contributors.

Imaging-based diagnosis of acute renal allograft rejection

Kidney transplantation is the best available treatment for patients with end stage renal disease. Despite the introduction of effective immunosuppressant drugs, episodes of acute allograft rejection still endanger graft survival. Since efficient treatment of acute rejection is available, rapid diagnosis of this reversible graft injury is essential. For diagnosis of rejection, invasive core needle biopsy of the graft is the "gold-standard". However, biopsy carries the risk of significant graft injury and is not immediately feasible in patients taking anticoagulants. Therefore, a non-invasive tool assessing the whole organ for specific and fast detection of acute allograft rejection is desirable. We herein review current imaging-based state of the art approaches for non-invasive diagnostics of acute renal transplant rejection. We especially focus on new positron emission tomography-based as well as targeted ultrasoundbased methods.

Combined liver and kidney transplantation in children and long-term outcome

Combined liver-kidney transplantation(CLKT)is a rarely performed complex surgical procedure in children and involves transplantation of kidney and either whole or part of liver donated by the same individual(usually a cadaver)to the same recipient during a single surgical procedure.Most common indications for CLKT in children are autosomal recessive polycystic kidney disease and primary hyperoxaluria type 1.Atypical haemolytic uremic syndrome,methylmalonic academia,and conditions where liver and renal failure co-exists may be indications for CLKT.CLKT is often preferred over sequential liver-kidney transplantation due to immunoprotective effects of transplanted liver on renal allograft;however,liver survival has no significant impact.Since CLKT is a major surgical procedure which involves multiple and complex anastomosis surgeries,acute complications are not uncommon.Bleeding,thrombosis,haemodynamic instability,infections,acute cellular rejections,renal and liver dysfunction are acute complications.The long-term outlook is promising with over 80%5-year survival rates among those children who survive the initial six-month postoperative period.

Clinical and pathological features of kidney transplant patients with concurrent polyomavirus nephropathy and rejection-associated endarteritis

AIM: To describe the clinicopathologic features of concurrent polyomavirus nephropathy(PVN) and endarteritis due to rejection in renal allografts.METHODS: We searched our electronic records database for cases with transplant kidney biopsies demonstrating features of both PVN and acute rejection(AR). PVN was defined by the presence of typical viral cytopathic effect on routine sections and positive polyomavirus SV40 large-T antigen immunohistochemistry. AR was identified by endarteritis(v1 by Banff criteria). All cases were subjected to chart review in order to determine clinical presentation, treatment course and outcomes. Outcomes were recorded with a length of follow-up of at least one year or time to nephrectomy. RESULTS: Of 94 renal allograft recipients who developed PVN over an 11-year period at our institution, we identified 7(7.4%) with viral cytopathic changes, SV40 large T antigen staining, and endarteritis in the same biopsy specimen, indicative of concurrent PVN and AR. Four arose after reduction of immunosuppression(IS)(for treatment of PVN in 3 and tuberculosis in 1), and 3 patients had no decrease of IS before developing simultaneous concurrent disease. Treatment consisted of reduced oral IS and leflunomide for PVN, and antirejection therapy. Three of 4 patients who developed endarteritis in the setting of reduced IS lost their grafts to rejection. All 3 patients with simultaneous PVN and endarteritis cleared viremia and were stable at 1 year of follow up. Patients with endarteritis and PVN arising in a background of reduced IS had more severe rejection and poorer outcome.CONCLUSION: Concurrent PVN and endarteritis may be more frequent than is currently appreciated and may occur with or without prior reduction of IS.

Diabetes mellitus is not associated with worse short term outcome in patients older than 65 years old post-liver transplantation

BACKGROUND Non-alcoholic fatty liver disease is a global health care challenge and a leading indication of liver transplantation(LT).Hence,more patients with diabetes mellitus(DM)are undergoing LT,especially,above the age of 65.AIM To evaluate the impact of DM on short-term outcomes post-LT in patients over the age of 65.METHODS We collected data of patients who underwent LT from January 2001 until December 2019 using our electronic medical record.We assessed the impact of DM on short-term outcomes,one-year,post-LT based on the following variables:Survival at one year;acute cellular rejection(ACR)rates;intensive care unit(ICU)and hospital length of stay;and readmissions.RESULTS Total of 148 patients who are 65 year or older underwent LT during the study period.The mean age is 68.5±3.3 years and 67.6%were male.The median Model for End-stage Liver Disease score at time of transplantation was 22(6-39),39%of patients had hepatocellular carcinoma and 77.7%underwent living donor LT.The one-year survival was similar between DM patients and others,91%.ACR occurred in 13.5%of patients(P=0.902).The median ICU stay is 4.5-day P=0.023.The rates of ICU and 90-d readmission were similar(P=0.821)and(P=0.194),respectively.CONCLUSION The short-term outcome of elderly diabetic patients undergoing LT is similar to others.The presence of DM in elderly LT candidates should not discourage physicians from transplant consideration in this cohort of patients.

Outcome of split liver transplantation vs living donor liver transplantation:A systematic review and meta-analysis

BACKGROUND The outcomes of liver transplantation(LT)from different grafts have been studied individually and in combination,but the reports were conflicting with some researchers finding no difference in both short-term and long-term outcomes between the deceased donor split LT(DD-SLT)and living donor LT(LDLT).AIM To compare the outcomes of DD-SLT and LDLT we performed this systematic review and meta-analysis.METHODS This systematic review was performed in compliance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines.The following databases were searched for articles comparing outcomes of DD-SLT and LDLT:PubMed;Google Scholar;Embase;Cochrane Central Register of Controlled Trials;the Cochrane Database of Systematic Reviews;and Reference Citation Analysis(https://www.referencecitationanalysis.com/).The search terms used were:“liver transplantation;”“liver transplant;”“split liver transplant;”“living donor liver transplant;”“partial liver transplant;”“partial liver graft;”“ex vivo splitting;”and“in vivo splitting.”RESULTS Ten studies were included for the data synthesis and meta-analysis.There were a total of 4836 patients.The overall survival rate at 1 year,3 years and 5 years was superior in patients that received LDLT compared to DD-SLT.At 1 year,the hazard ratios was 1.44(95%confidence interval:1.16-1.78;P=0.001).The graft survival rate at 3 years and 5 years was superior in the LDLT group(3 year hazard ratio:1.28;95%confidence interval:1.01-1.63;P=0.04).CONCLUSION This meta-analysis showed that LDLT has better graft survival and overall survival when compared to DD-SLT.

Outcome of Renal Transplantation at Ahmed Gasim Cardiac and Renal Transplant Centre in Sudan-2014

Background: Although not life-saving procedures like liver or heart transplantation, renal transplantation is the preferred treatment for many patients with end-stage renal disease because it improves patients’ quality of life, while other forms of renal replacement therapy (RRT) such as haemodialysis (HDX) shown to regain only 10% of the patient’s renal function [1]. Transplantation releases patients from the dietary and fluid restrictions and the physical constraints imposed by other forms of (RRT), patients become able to return to their normal activities. Patient’s 5-year survival is higher post transplant. Patients and methods: This is Descriptive, retro-prospective, cross sectional analytic and multicentre study done in Ahmed Gasim Cardiac and Renal Transplant Centre including 105 patients. After meeting the Inclusion Criteria and exclusion Criteria, then cases were selected and written in constructed questionnaire. The aim of the study was to evaluate the outcome of renal transplantation in Sudan. Results: 105 cases were used with male predominate and ratio male to female ratio 3:1, the main age of presentation between 31 - 45 years, most of the patients discharge uneventful with good outcome. During one-year follow-up following renal transplantation. Patient survival 95.2 % graft survival 82.4%. Overall morbidity shows 70.5%. Conclusion: this study showed that the one-year patient survival of 95.2%. Actuarial one-year graft survival of 92.4%. Renal transplantation complications can be reduced by meticulous preoperative workup including good cardiovascular assessment, tissue mismatch and BMI good postoperative follow up for early detection of graft rejection and long-term complications and finally patient education.

Role of novel biomarkers in kidney transplantation

Clinical application of biomarkers is an integral component of transplant care.Clinicians and scientists alike are in search of better biomarkers than the current serologic(serum creatinine,donor-specific antibodies),urine-derived(urinalysis,urine protein),and histologic ones we now use.The science behind recent biomarker discovery spans across multiple molecular biologic disciplines,including transcriptomics,proteomics,and metabolomics.Innovative methodology and integration of basic and clinical approaches have allowed researchers to unearth molecular phenomena preceding clinical disease.Biomarkers can be classified in several ways.In this review,we have classified them via their origin and outcome:Primarily immunologic,i.e.,representative of immune regulation and dysfunction and non-immunologic,pertaining to delayed graft function,cardiovascular events/mortality,infection,malignancy,posttransplant diabetes,graft,and patient survival.Novel biomarker uses to guide the diagnosis and management of transplant-related outcomes is a promising area of research.However,the use of biomarkers to predict outcomes after kidney transplantation is not well studied.In this review,we summarize the recent studies illustrating biomarker use and transplant outcomes.

Antibody induction therapy in adult kidney transplantation: A controversy continues

Antibody induction therapy is frequently used as an adjunct to the maintenance immunosuppression in adult kidney transplant recipients. Published data support antibody induction in patients with immunologic risk to reduce the incidence of acute rejection(AR) and graft loss from rejection. However, the choice of antibody remains controversial as the clinical studies were carried out on patients of different immunologic risk and in the context of varying maintenance regimens. Antibody selection should be guided by a comprehensive assessment of immunologic risk, patient comorbidities, financial burden as well as the maintenance immunosuppressives. Lymphocyte-depleting antibody(thymoglobulin, ATGAM or alemtuzumab) is usually recommended for those with high risk of rejection, although it increases the risk of infection and malignancy. For low risk patients, interleukin-2 receptor antibody(basiliximab or daclizumab) reduces the incidence of AR without much adverse effects, making its balance favorable in mostpatients. It should also be used in the high risk patients with other medical comorbidities that preclude usage of lymphocyte-depleting antibody safely. There are many patients with very low risk, who may be induced with intravenous steroids without any antibody, as long as combined potent immunosuppressives are kept as maintenance. In these patients, benefits with antibody induction may be too small to outweigh its adverse effects and financial cost. Rituximab can be used in desensitization protocols for ABO and/or HLA incompatible transplants. There are emerging data suggesting that alemtuzumab induction be more successful than other antibody for promoting less intensive maintenance protocols, such as steroid withdrawal, tacrolimus monotherapy or lower doses of tacrolimus and mycophenolic acid. However, the long-term efficacy and safety of these unconventional strategies remains unknown.

Proteomics for rejection diagnosis in renal transplant patients: Where are we now?

Rejection is one of the key factors that determine the long-term allograft function and survival in renal transplant patients. Reliable and timely diagnosis is important to treat rejection as early as possible. Allograft biopsies are not suitable for continuous monitoring of rejection. Thus, there is an unmet need for non-invasive methods to diagnose acute and chronic rejection. Proteomics in urine and blood samples has been explored for this purpose in 29 studies conducted since 2003. This review describes the different proteomic approaches and summarizes the results from the studies that examined proteomics for the rejection diagnoses. The potential limitations and open questions in establishing proteomic markers for rejection are discussed, including ongoing trials and future challenges to this topic.

Modern Immunosuppressive Therapy in Kidney Transplantation

Immunosuppressive therapy is a key component for successful kidney transplantation. It is commonly believed that more intensive immunosuppression is needed initially to prevent rejection episodes and less immunosuppression is subsequently maintained to minimize the overall risk of infection and malignancy. The selection of drugs should be guided by a comprehensive assessment of the immunologic risk, patient comorbidities, financial cost, drug efficacy and adverse effects. Lymphocyte-depleting antibody induction is recommended for patients with high immunologic risk, while IL-2R antibody can be used for low or moderate risk patients. Patients with very low risk may be induced with intravenous steroids without using an antibody. A maintenance regimen typically consists of a low-dose of steroid combined with two of the four class drugs: calcineurin inhibitor (tacrolimus or cyclosporine), antimetabolite (mycophenolate mofetil or enteric coated mycophenolate sodium), mTOR inhibitor (sirolimus or everolimus) and costimulation blocker (belatacept). Currently in the USA, the most popular maintenance is the combination of corticosteroid, mycophenolic acid and tacrolimus. Steroid minimization, or calcineurin inhibitor free or withdrawal should be limited to the highly selected patients with low immunological risk. Recently, the novel biological agent belatacept-based maintenance has demonstrated a significantly better renal function and improved cardiovascular and metabolic profile, which may provide hope for an ultimate survival benefit.

Biomarkers and a tailored approach for immune monitoring in kidney transplantation

A literature review on immune monitoring in kidney transplantation produced dozens of research articles and a multitude of promising biomarkers,all in the quest for the much sought after-but perennially elusive-"holy grail" of kidney biomarkers able to unequivocally predict acute transplant rejection vs non-rejection.Detection methodologies and study designs were many and varied.Hence the motivation for this editorial,which espouses the notion that in today's kidney transplantation milieu,the judicious use of disease classifiers tailored to specific patient immune risks may be more achievable and productive in the long run and confer a greater advantage for patient treatment than the pursuit of a single "omniscient" biomarker.In addition,we desire to direct attention toward greater scrutiny of biomarker publications and decisions to implement biomarkers in practice,standardization of methods in the development of biomarkers and consideration for adoption of "biomarker-driven" biopsies.We propose "biomarkerdriven" biopsies as an adjunctive to and/or alternative to random surveillance(protocol) biopsies or belated indication biopsies.The discovery of a single kidney transplantation biomarker would represent a major breakthrough in kidney transplantation practice,but until that occurs-if ever it does occur,other approaches offer substantial potential for unlocking prognostic,diagnostic and therapeutic options.We conclude our editorial with suggestions and recommendations for productively incorporating current biomarkers into diagnostic algorithms and for testing future biomarkers of acute rejection in kidney transplantation.

Impact of acute rejection episodes on long-term renal allograft survival

Objective To assess the impact of the number, and time of acute rejection (AR) and outcome of anti-rejection therapy on the long-term survival of renal allografts and the relative risk factors.Methods The Kaplan-Meier analysis and log-rank test were used to calculate the survival rates of patients and grafts in no acute rejection group (NAR, 895 patients), 1 rejection episode group (1AR, 183), 2 and more than 2 rejection episodes group (2AR, 17), acute rejection group [ AR (1 AR + 2AR), 200], early acute rejection group (within 90 days after transplantation, EAR, 125), late acute rejection group (91 days later, LAR, 58), completely AR reversed group (CAR, 105), and incompletely AR reversed group (IAR, 68), The relative risk factors were analyzed by the Cox proportional hazards regression.Results The 5- and 10-year survival rates of renal allografts were 75. 4% and 17.1% in AR and 93. 2% and 86. 5% in the NAR group ( P<0. 0001). The long-term graft survival was much lower in the 2AR group than in the NAR or 1 AR groups ( P <0. 0001 and P = 0. 002, respectively). It was similar in either the NAR or CAR groups ( P = 0. 31), but it was significantly lower ( P<0. 0001) in the IAR group. Multivariate Cox regression analysis revealed that the outcome of anti-rejection therapy is an important risk factor affecting the long-term survival of allografts.Conclusions AR is significantly associated with poor long-term survival of renal allografts. But the long-term graft survival of patients with one acute rejection but completely reversed is not significantly different from that of patients without acute rejection.

Changes in dendritic cells and dendritic cell subpopulations in peripheral blood of recipients during acute rejection after kidney transplantation

Background Advances in transplantation immunology show that the balance between dendritic cells （DCs） and their subsets can maintain stable immune status in the induction of tolerance after transplantation. The aim of this study was to investigate if DCs and DC subpopulations in recipient peripheral blood are effective diagnostic indicators of acute rejection following kidney transplantation. Methods Immunofluorescent flow cytometry was used to classify white blood cells （WBCs）, the levels of mononuclear cells and DCs （including the dominant subpopulations, plasmacytoid DC （pDC） and myeloid DC （mDC）） in peripheral blood at 0, 1, 7, and 28 days and 1 year after kidney transplantation in 33 patients. In addition, the blood levels of interleukin-10 （IL-10） and IL-12 were monitored before and after surgery. Fifteen healthy volunteers served as normal controls. Patients were undertaking hemodialysis owing to uremia before surgery. Results The total number of DCs, pDC, and mDC in peripheral blood and the pDC/mDC ratio were significantly lower in patients than controls （P 〈0.05）. Peripheral DCs suddenly decreased at the end of day 1, then gradually increased through day 28 but remained below normal levels. After 1 year, levels were higher than before surgery but lower than normal. The mDC levels were higher in patients with acute rejection before and 1 day after surgery （P 〈0.005）. There was no significant difference in IL-10 and IL-12 levels between patients with and without acute rejection. Conclusion The changes in DCs and DC subpopulations during the acute rejection period may serve as effective markers and referral indices for monitoring the immune state, and predicting rejection and reasonably adjusting immunosuppressants.

Early Immunosuppressive Exposure of Enteric-Coated-Mycophenolate Sodium Plus Tacrolimus Associated with Acute Rejection in Expanded Criteria Donor Kidney Transplantation

Background： lmmunosuppressive agents are still inefficient in preventing biopsy-proven acute rejection （BPAR） alter expanded criteria donor （ECD） kidney transplantation. The aim of this study was to investigate the relationships between early imrnunosuppressive exposure and the development of BPAR. Methods： We performed a retrospective study of 58 recipients of ECD kidney transplantation treated with enteric-coated-mycophenolate sodium, tacrolirnus （Tac）, and prednisone. The levels of mycophenolic acid-area under the curve （MPA-AUC）0-12h and Tac C0 were measured at the 1st week and the 1st month posttransplant, respectively. The correlation was assessed by multivariate logistic regression. Results： The occurrence rates of BPAR and antibody-mediated rejection were 24.1% and 10.3%, respectively. A low level of MPA-AUC0-12h at the 1st week posttransplant was found in BPAR recipients （38.42 ± 8.37 vs. 50.64 ± 13.22, P 〈 0.01）. In addition, the incidence of BPAR was significantly high （P 〈 0.05） when the MPA-AUC0-12h level was 〈30 mg·h-1·L-1 at the 1st week （ 15.0% vs. 44.4%） or the Tac C0 was 〈4 ng/ml at the 1 st month posttransplant （33.3% vs. 21.6%）. Multivariable logistic regression analysis showed that the MPA-AUC 0-12 h at the 1st week （OR： 0.842, 95% CI： 0.784-0.903） and the Tac C0 at the 1st month （OR： 0.904, 95% C7： 0.822-0.986） had significant inverse correlation with BPA R （ P 〈 0.05 ）. Conclusions： Low-level exposure of MPA and Tac C0 in the early weeks posttransplant reflects an increased acute rejection risk, which suggested that MPA-AUC0-12h 〈30 mg·h-1·L -1 and Tac C0 〈4 ng/ml should be avoided in the first few weeks alter transplantation.