Average Tacrolimus Trough Level in the First Month After Transplantation May Predict Acute Rejection

Background

Although tacrolimus is one of the essential drugs used for the prevention of rejection in kidney recipients, target trough levels are not well established. In this study, we aimed to investigate the association between average tacrolimus trough levels (TTLs) of the first month after transplantation and biopsy-proven acute rejection (BPAR) during the first 12 months after transplant.

Acute Antibody-Mediated Rejection Following Heart Transplantation

Acute antibody-mediated rejection (AMR) in heart transplantation is often associated with hemodynamic compromise, and is associated with increased mortality and development of accelerated transplant coronary artery disease (TCAD). The diagnosis of AMR has historically been controversial and outcomes with aggressive immunosuppressive therapy including plasmapheresis and cyclophosphamide are poor. Advances in diagnostic techniques like the demonstration of immunopathologic evidence for antibody-mediated rejection by deposition of the complement split product C4d in tissue and detection of anti-HLA antibodies by flow cytometry will assist in further characterizing AMR. Immunosuppression targeting B-lymphocytes and use of m-TOR inhibitors to alter the predilection to develop TCAD and improve survival in AMR remains to be proven.     

Impact of Acute Rejection Episodes on Long-Term Graft Survival Following Simultaneous Kidney-Pancreas Transplantation

Although it is well established that acute rejection is one of the major risk factors for chronic graft loss following kidney transplantation, its effect on long-term graft survival following simultaneous kidney-pancreas transplants (SKPTs) is less well known. We analyzed a large cohort of SKPTs and cadaver kidney transplants reported to the United Network for Organ Sharing database during 1988-97, to determine the impact of acute rejection episodes on long-term kidney and pancreas graft survival. Only patients whose kidney and pancreas grafts had survived for at least 1 year were included. Other potential risk factors influencing long-term graft survival were included in the analysis. Of the 4251 SKPTs, 45% had no acute rejection, 36% had kidney only rejection, 3% had pancreas only rejection, and 16% had both kidney and pancreas rejection within the 1st year post transplant. The 5-year kidney and pancreas graft survival rates adjusted for other risk factors were 91% and 85%, respectively; for those with no acute rejection episodes, 88% and 84%, respectively; for those with kidney only rejection, 94% and 83%, respectively; for those with pancreas only rejection; and 86% and 78%, respectively, for those with both kidney and pancreas rejection. The relative risk (RR) of kidney graft failure was 1.32 when acute rejection involved the kidney graft only, while the RR was 1.53 when the rejection involved both organs. We conclude that acute rejection episodes have a negative impact on the long-term kidney graft survival in the SKPT population similar to that in the cadaver kidney transplant population. Patients who had acute rejection episodes of both kidney and pancreas have the worst long-term graft survival.     

Acute Rejection in Kidney Transplantation and Early Beginning of Tacrolimus

BackgroundAlthough tacrolimus is an effective immunosuppressive drug used for preventing biopsy proven acute rejection (BPAR) in kidney transplanted patients, its nephrotoxicity may compromise renal function and lead to delayed initiation because of its side effects. This study aimed to evaluate the safety of early initiation of tacrolimus in the occurrence of BPAR during the first 90 days post transplant.MethodsWe conducted a retrospective cohort study involving 315 patients who underwent kidney transplantation from 2015 to 2017. Comparisons were performed between 2 groups according to whether the start time of tacrolimus therapy was delayed or not delayed. Cox proportional hazards models were used to examine the association between variables and the occurrence of BPAR.ResultsThe incidence of BPAR was 14.9% (n = 47) and it was significantly higher in the delayed group (19.4% vs 6.4%; P = .002). Delayed initiation tacrolimus group was significantly associated with the risk of BPAR (hazard ratio: 2.95; P < .036). The overall mortality rate was 2.5% (n = 8) and there was no association between delayed initiation therapy and death (P = .56).ConclusionOur study confirmed that delayed initiation of tacrolimus in patients with delayed graft function is associated with a high risk of BPAR.     

Pulmonary Capillaritis as a Manifestation of Acute Humoral Allograft Rejection Following Infant Lung Transplantation

Pulmonary capillaritis has been described in adult lung transplant recipients, but has not been previously reported in pediatric recipients. We report a case of posttransplant pulmonary capillaritis in an 8-month-old infant, and demonstrate evidence of C4d deposition and B-lymphocytes in the allograft, donor anti-HLA antibodies in the serum and a clinical and immunohistochemical response to anti-CD20 monoclonal antibody (rituximab) therapy. These findings strongly support the hypothesis that pulmonary capillaritis may represent a form of acute humoral rejection in the lung allograft that is less common than, and clinically and histologically distinct from, typical acute cellular rejection.     

Severe Acute Cellular Rejection With High-Grade Lymphocytic Bronchiolitis Following Transition from Tacrolimus to Belatacept in a Lung Transplantation Recipient: A Case Report

This case report describes a lung transplantation recipient who developed severe acute cellular rejection with high-grade lymphocytic bronchiolitis after transition to a calcineurin-free regimen using belatacept. A 53-year-old man who had undergone lung transplantation 3 years prior developed progressive chronic kidney disease related to tacrolimus. He was transitioned off tacrolimus to belatacept to prevent the need for dialysis. He was admitted 2 months later with acute hypoxemic respiratory failure. Video-assisted thoracic surgery biopsy showed acute fibrinous and organizing pneumonia and A4B2 rejection. He subsequently developed chronic lung allograft dysfunction. This case illustrates the potential increased risk of acute rejection associated with belatacept maintenance immunosuppression.     

Transient Elastography in Acute Cellular Rejection Following Liver Transplantation: Systematic Review

Background

Transient elastography (TE) is a noninvasive technique that measures liver stiffness. When an inflammatory process is present, this is shown by elevated levels of stiffness. Acute cellular rejection (ACR) is a consequence of an inflammatory response directed at endothelial and bile epithelial cells, and it is diagnosed through liver biopsy. This is a systematic review of the viability of TE in ACR following liver transplantation.

他克莫司撤药诱发大鼠肝移植急性排斥反应的病理学观察与分析

目的建立大鼠肝移植急性排斥反应动物模型,观察大鼠肝移植术后他克莫司撤药诱发受体急性排斥反应的肝脏动态病理学变化,为临床肝移植术后他克莫司停药或者用药不规律所致急性排斥反应的预测和评估提供理论依据。方法通过Kamada二袖套法,建立雄性DA大鼠至Lewis大鼠的原位肝移植模型60例。受体大鼠术前1 d和术后7 d内饲喂治疗剂量的他克莫司,之后半量递减至停药。分别于术后7、14、21及28 d处死部分受体大鼠,获取肝组织标本,观察受体大鼠肝脏大体和镜下的动态病理学改变,并进行排斥活动指数评分,同时观察受体大鼠的术后生存时间。结果受体大鼠术后7 d内由于受他克莫司的保护,肝脏未出现典型的急性排斥反应表现,至术后14 d由于他克莫司的减量及撤出,迅速发生肝脏的急性排斥反应,术后14、21及28 d排斥活动指数评分分别为(3.7±0.9)分(、6.3±0.9)分和(8.1±0.7)分。受体术后生存时间为(20.85±0.71)d,中位生存期为21 d。结论通过围手术期短期饲喂治疗剂量他克莫司并逐渐减量至撤药诱发肝移植大鼠急性排斥反应模型术后的急性排斥反应,动态观察该实验条件下排斥反应发生的时限和严重程度,对临床肝移植术后类似情况下所发生的急性排斥反应具有一定的预测价值和严重程度评估价值。     

Tacrolimus Trough Levels,Rejection and Renal Impairment in Liver Transplantation: A Systematic Review and Meta‐Analysis

We hypothesized that current trough concentrations of tacrolimus after liver transplantation are set too high, considering that clinical consequences of rejection are not severe while side effects are increased. We systematically reviewed 64 studies (32 randomized controlled trials and 32 observational studies) to determine how lower tacrolimus trough concentrations than currently recommended affect acute rejection rates and renal impairment. Among randomized trials the mean of tacrolimus trough concentration during the first month was positively correlated with renal impairment within 1 year (r = 0.73; p = 0.003), but not with acute rejection, either defined using protocol biopsies (r =?0.37; p = 0.32) or not (r = 0.11; p = 0.49). A meta‐analysis of randomized trials directly comparing tacrolimus trough concentrations (five trials for acute rejection [n = 957] and two trials for renal impairment [n = 712]) showed that “reduced tacrolimus” trough concentrations (<10 ng/mL) within the first month after liver transplantation were associated with less renal impairment at 1 year (RR = 0.51 [0.38–0.69]), with no significant influence on acute rejection (RR = 0.92 [0.65–1.31]) compared to “conventional tacrolimus” trough levels (>10 ng/mL). Lower trough concentrations of tacrolimus (6–10 ng/mL during the first month) would be more appropriate after liver transplantation. Regulatory authorities and the pharmaceutical industry should allow changes of regulatory drug information.     

Composite Tissue Vasculopathy and Degeneration Following Multiple Episodes of Acute Rejection in Reconstructive Transplantation

Transplant vasculopathy has not been systematically investigated in composite tissue allotransplantation (CTA). The impact of multiple acute rejections (ARs) on long‐term graft outcomes in reconstructive transplantation remains unknown. This study in a rat hind‐limb allotransplantation model systematically analyzes vasculopathy and tissue‐specific pathological changes secondary to multiple AR episodes. LEW rats were transplanted with BN rat hind limbs and treated as follows: Group 1 (Iso): isografts. Group 2 (CsA): Cyclosporine (CsA) qd; Group 3 (mult AR): CsA and dexamethasone only when AR was observed. No AR was observed in Groups 1 and 2. Multiple AR were observed in Group 3, and each episode was completely reversed (clinically) with pulsed CsA + dexamethasone treatment. Group 3 animals demonstrated significant vascular lesions along with skin and muscle atrophy, upregulation of profibrotic gene expression and fibrosis when compared to Groups 1 and 2. In addition, allograft bone was sclerotic, weak and prone to malunion and nonunion. Interestingly, vasculopathy was a late finding, whereas muscle atrophy with macrophage infiltration was seen early, after only a few AR episodes. Taken together, multiple AR episodes lead to vasculopathy and tissue‐specific pathology in CTA. This is the first evidence of ‘composite tissue vasculopathy and degeneration (CTVD)’ in CTA.     

Bronchial Complications Following Lung Transplantation

Introduction

Bronchial complications owing to the airway anastomosis in lung transplantation are important causes of morbidity and mortality. They occur in up to 27% of cases as defined by stenosis, necrosis, and dehiscence. Treatment depends on the type of complication.

Objective

To report our experience to treat this complication.

Methods

Between 2000 and 2007, we performed 71 lung transplants of which 36 were bilateral. The total number of anastomoses was 107:52 to the right and 55 to the left. The telescoping technique was initially used (14 initial unilateral transplants), and after October, 2003 it was changed to an end-to-end anastomosis (57 transplants and 93 anastomoses).

Results

Eight patients developed bronchial complications including two that were bilateral. There were 4 stenosis, 3 dehiscences, and 3 necrosis complications (9.4%). The complication rate for telescoping anastomosis was 21.4%, and for the end-to-end technique, 7.5%. The treatment of the stenosis used metallic or plastic self-expandable stents. Two bronchial dehiscences resulted in case of bronchopleural fistulae, empyema, and death; the other patient experienced spontaneous resolution. Concerning bronchial necrosis, 1 patient developed fistulization to the pulmonary artery and massive hemoptysis, and the other with bilateral necrosis, a spontaneous resolution.

Conclusion

Our bronchial anastomosis complication rate was comparable with that in other reports. The rate for the telescoping technique was greater compared with the end-to-end technique. The treatment of bronchial stenosis with a self-expandable prosthesis showed good results.     

Minimal Acute Rejection after Lung Transplantation: A Risk for Bronchiolitis Obliterans Syndrome

Bronchiolitis obliterans syndrome (BOS) is a major cause of lung allograft dysfunction. Although previous studies have identified mild to severe rejection (grade>or=A2) as a risk factor for BOS, the role of minimal rejection (grade A1) remains unclear. To determine if A1 rejection by itself is a risk factor for BOS, we performed a retrospective cohort study on 228 adult lung transplant recipients over a 7-year period. Cohorts were defined by their most severe rejection episode (none, A1 only, and >or=A2) and analyzed for the subsequent development and progression of BOS using univariate and multivariate time-dependent Cox regression analysis. In the univariate model, the occurrence of isolated minimal rejection was a risk factor for all stages of BOS. Similarly, multivariate models that included HLA mismatch, cytomegalovirus pneumonitis, community acquired viral infection, underlying disease and type of transplant demonstrated that A1 rejection was a distinct risk factor for BOS. Furthermore, the associated risk with A1 rejection was slightly greater than the risk from >or=A2 and treatment of A1 rejection decreased the risk for subsequent BOS stage 1. We conclude that minimal rejection is associated with an increased risk for BOS development and progression that is comparable to A2 rejection.     

Role of Resistive Index Measurement in Diagnosis of Acute Rejection Episodes Following Successful Kidney Transplantation

Objective

This study was performed to evaluate the role of resistive index (RI) in the diagnosis of rejection episodes following successful kidney transplantation.

Materials and Methods

One hundred and one unrelated living first kidney allograft adult recipients (75 males and 26 females) of overall mean age of 39 years were enrolled and prospectively followed for 6 months. The measurement of RI by Doppler ultrasonography was performed in all patients on days 3 and 7 as well as at months 1, 3, and 6 in addition to when there was graft dysfunction. We determined serum creatinine and cyclosporine levels.

Results

Twenty-seven patients (26.7%) experienced 33 acute rejection episodes during the follow-up. There were significant differences between mean RI among patients with normal function vs rejection: 0.606 ± 0.065 vs 0.866 ± 0.083 (P < .05), respectively. Overall, elevated levels of cyclosporine, ischemic acute tubular necrosis (ATN), and renal artery thrombosis were observed in 8, 5, and 3 patients, respectively. No association was observed between these factors and RI.

Conclusions

RI was significantly higher in patients with acute rejection episodes. It had no association with ATN or cyclosporine toxicity. Hence, RI may be useful to diagnose acute renal allograft rejection following renal transplantation.     

Mycophenolic Acid 12-h Trough Level Monitoring in Renal Transplantation: Association with Acute Rejection and Toxicity

Studies of renal transplantation utilizing trough plasma level monitoring of mycophenolic acid (MPA) have shown inconsistent associations with toxicity and rejection. In this study, 5600 12-h trough MPA samples from 121 renal transplant recipients immunosuppressed with mycophenolate mofetil (MMF) and tacrolimus in a steroid sparing protocol (steroids for 7 days only) were sequentially analyzed. Higher MPA levels were associated with lower hemoglobin concentrations and anemia (hemoglobin <10 g/dL). Similarly, higher MPA levels were associated with lower total white cell counts and an increased incidence of leucopenia (total white cell count <4.0 x 10(9)/L). Hypoalbuminemia and renal impairment were also associated with hemotoxicity. MMF-associated diarrhea and viral infection were associated with higher MPA levels. Conversely, biopsy-proven acute rejection within the first month post-transplantation was associated with lower MPA levels. Anti-CD25 antibody induction was also associated with reduced rejection rates. No association was seen between MPA levels and platelet count, thrombocytopenia or bacterial infection. An MPA level of 1.60 mg/L early post-transplantation best discriminated patients with and without rejection, and an MPA level of 2.75 mg/L best discriminated patients with and without toxicity later post-transplantation.