Severe Acute Cellular Rejection Research Articles

Validation of the usefulness of 2-dimensional strain parameters to exclude acute rejection after heart transplantation: a multicenter study

Introduction and objectivesTwo-dimensional speckle-tracking echocardiography has emerged as a promising alternative to endomyocardial biopsy to rule out acute cellular rejection after orthotopic heart transplantation (OHT) in single center studies. In an original cohort, 15.5% and 17% of cutoff points for left ventricular global longitudinal strain (LVGLS) and free-wall right ventricular longitudinal strain, respectively, achieved 100% negative predictive value to exclude moderate or severe acute cellular rejection (ACR ≥ 2R). Our objective was to demonstrate the usefulness of speckle-tracking and validate these cutoff points in an external cohort. MethodsA prospective, multicenter study that included patients who were monitored during their first year after OHT was conducted. Echocardiographic studies analyzed by local investigators were compared with simultaneous paired endomyocardial biopsies samples. ResultsA total of 501 endomyocardial biopsy-echocardiographic studies were included in 99 patients. ACR≥2R was present in 7.4% of samples. LVGLS and free-wall right ventricular longitudinal strain were significantly reduced during ACR≥2R on univariate analysis. On multivariate analysis, LVGLS was independently associated with the presence of ACR≥2R. The original cutoff points demonstrated a negative predictive value of 94.3% to exclude ACR≥2R. ConclusionsThis study maintained a strong negative predictive value to exclude ACR≥2R after OHT and LVGLS was independently associated with the presence of ACR≥2R. We propose the use of speckle-tracking, especially LVGLS, as part of the noninvasive diagnosis and management of ACR.

Association of More Intensive Induction With Less Acute Rejection Following Intestinal Transplantation: Results of 445 Consecutive Cases From a Single Center.

In intestinal transplantation, acute cellular rejection (ACR) remains a significant challenge to achieving long-term graft survival. It is still not clear which are the most important prognostic factors. We performed a Cox multivariable analysis of the hazard rates of developing any ACR, severe ACR, and cause-specific graft loss during the first 60 months posttransplant among 445 consecutive intestinal transplant recipients at our institution since 1994. Of particular interest was to determine the prognostic influence of induction type: rabbit antithymocyte globulin (rATG; 2 mg/kg × 5)/rituximab (150 mg/m × 1; begun in 2013), alemtuzumab (2001-2011), and less intensive forms. First ACR and severe ACR occurred in 61.3% (273/445) and 22.2% (99/445) of cases. The following 3 multivariable predictors were associated with significantly lower hazard rates of developing ACR and severe ACR: transplant type modified multivisceral or full multivisceral (P = 0.0009 and P < 0.000001), rATG/rituximab induction (P < 0.000001 and P < 0.01), and alemtuzumab induction (P = 0.004 and P = 0.07). For both ACR and severe ACR, the protective effects of rATG/rituximab and alemtuzumab were highly significant (P ≤ 0.000005 for ACR; P ≤ 0.01 for severe ACR) but only during the first 24 days posttransplant (when the ACR hazard rate was at its peak). The prognostic effects of rATG/rituximab and alemtuzumab on ACR/severe ACR disappeared beyond 24 days posttransplant (ie, nonproportional hazards). While significant protective effects of both rATG/rituximab and alemtuzumab existed during the first 6 months posttransplant for the hazard rate of graft loss-due-to-rejection (P = 0.01 and P = 0.003), rATG/rituximab was additionally associated with a consistently lower hazard rate of graft loss-due-to-infection (P = 0.003). All significant effects remained after controlling for the propensity-to-be-transplanted since 2013. More intensive induction was associated with a significant lowering of ACR risk, particularly during the early posttransplant period.

Severe Late-Onset Acute Cellular Rejection in a Pediatric Patient With Isolated Small Intestinal Transplant Rescued With Aggressive Immunosuppressive Approach: A Case Report

Small intestinal transplantation is performed for patients with intestinal failure who failed other surgical and medical treatment. It carries notable risks, including, but not limited to, acute and chronic cellular rejection and graft malfunction. Late severe acute intestinal allograft rejection is associated with increased risk of morbidity and mortality and, in the majority of cases, ends with total enterectomy. It usually results from subtherapeutic immunosuppression or nonadherence to medical treatment. We present the case of a 20-year-old patient who underwent isolated small bowel transplant for total intestinal Hirschsprung disease at age 7. Due to medication nonadherence, she developed severe late-onset acute cellular rejection manifested by high, bloody ostomy output and weight loss. Ileoscopy showed complete loss of normal intestinal anatomic landmarks and ulcerated mucosa. Graft biopsies showed ulceration and granulation tissue with severe architectural distortion consistent with severe intestinal graft rejection. She initially received intravenous corticosteroids and increased tacrolimus dose without significant improvement. Her immunosuppression was escalated to include infliximab and finally antithymocyte globulin. Graft enterectomy was considered repeatedly; however, clinical improvement was noted eventually with evidence of histologic improvement and salvage of the graft. The aggressive antirejection treatment was complicated by development of post-transplant lymphoproliferative disorder that resolved with reducing immunosuppression. Her graft function is currently maintained on tacrolimus, oral prednisone, and a periodic infliximab infusion. We conclude that a prompt and aggressive immunosuppressive approach significantly increases the chance of rescuing small bowel transplant rejection.

2235 Nivolumab-Induced Severe Allograft Rejection in Recurrent Post-Transplant Hepatocellular Carcinoma

INTRODUCTION: Hepatocellular carcinoma (HCC) is an established indication for liver transplantation (LT), but recurrent HCC post LT presents a unique therapeutic challenge. Nivolumab is an immune checkpoint inhibitor (ICPI) approved for treatment of HCC, but data on its safety following LT is limited. We present a case of Nivolumab-induced severe, steroid-resistant acute cellular rejection (ACR) in a patient with recurrent HCC post LT, treated successfully with thymoglobulin and plasmapheresis. CASE DESCRIPTION/METHODS: A 64-year-old male was noted to have evidence of locally advanced recurrent HCC on surveillance imaging two years post-LT. Systemic therapy using Sorafenib had to be discontinued due to severe proteinuria. Given limited therapeutic options and evidence of progressive disease, a decision was made to initiate Nivolumab. A week later, liver tests were elevated and continued to worsen significantly (peak values 3 weeks post infusion: ALT 424 U/L, AST 215 U/L, ALP 1074 IU/L, Br 16 mg/dL). Further infusions were discontinued. Liver biopsy revealed features of ACR with moderate portal inflammation, patchy bile duct injury and endotheliitis. Since ACR was resistant to high dose steroids, thymoglobulin was administered with some improvement. However, given persistent liver test elevation, we proceeded with plasmapheresis and after 5 sessions, marked improvement was noted and repeat biopsy showed resolution of ACR (Figure 1). DISCUSSION: Nivolumab, a monoclonal antibody that targets programmed cell death protein 1, was FDA approved in 2017 for the treatment of HCC in patients previously treated with Sorafenib. However, there is limited experience with its use in solid organ transplant recipients. The immunological mechanism of nivolumab induced ACR is unclear and there is no consensus on management. As with our patient, none of the reported cases responded to high-dose steroid therapy. Use of thymoglobulin and plasmapheresis has not been reported in this setting previously. Even though plasmapheresis would likely not impact nivolumab-induced T cell–mediated immune rejection, given its long half- life, we hypothesized that plasmapheresis could help by removing the medication from the circulation. Severe ACR with ICPI therapy could result in allograft failure, with limited therapeutic options. Factors that contribute to ACR and whether this may be impacted by length of time after LT remain unclear. There is a critical need for safe and effective systemic options for treatment of recurrent HCC post-LT.

2399 West Nile Encephalitis in a Post-Liver Transplant Patient

INTRODUCTION: West Nile Virus (WNV) is a neurotropic flavivirus that is transmitted from animals to humans by the bite of the Aedes, Anaphales, or Culex mosquito, with disease incidence peaking in the late summer and early fall. It is the leading cause of arboviral illness in the U.S. While many infected with WNV are asymptomatic, 25% of patients develop fever, and less than 1% of patients will develop neurologic symptoms. Age over 75-years old and immunosuppressed state are risk factors for developing neuroinvasive disease. CASE DESCRIPTION/METHODS: A 65-year old woman with a history of HCV cirrhosis complicated by HCC status post successful orthotopic liver transplantation (OLT) in 2016 compliant with tacrolimus and everolimus immunosuppression (ISP) presented with painless jaundice and acute transaminemia. Liver biopsy revealed severe acute cellular rejection (ACR), so steroids and thymoglobulin were started. Tacrolimus was increased and everolimus was changed to mycophenolate mofetil. Clinically, she appeared well and her LFTs responded to treatment. Suddenly, she developed fever to 103º associated with bilateral hand tremors. Infectious workup was obtained, and she was started on broad-spectrum antibiotics. Initially, symptoms were attributed to changes in ISP and treatment of ACR. However, she developed progressively worsening dyskinesia and encephalopathy eventually requiring intubation. Given initial negative infectious workup, lumbar puncture was obtained; see Table 1. HSV, VZV, and Lyme PCR as well as VDRL in the CSF were negative. Given clinical symptoms, positive WNV IgM in the CSF, and MRI Brain concerning for WNV neuroinvasive disease, patient was treated with IVIG for 5 days. WNV IgG became positive as well on repeat lumbar puncture 2 weeks later. Patient’s encephalopathy improved, and she was able to be extubated. DISCUSSION: There may be a delay in diagnosis and treatment of WNV encephalitis in post-liver transplant patients as neurologic symptoms may be attributed to ISP or as in this patient, to the treatment of acute cellular rejection. West Nile encephalitis must remain on the differential diagnosis when neurologic symptoms are present in a post-liver transplant patient, especially in endemic areas during the summer and fall months. A change in this patient’s ISP for the treatment of ACR may have caused the development of a more severe, neuroinvasive response to WNV infection and ISP management in such patients should be studied further.

P4.19: Incidence and severity of acute cellular rejection in the recipients of small bowel transplantation in Taiwan

P4.19: Incidence and severity of acute cellular rejection in the recipients of small bowel transplantation in Taiwan

P1.57: Severe Late Onset Acute Cellular Rejection in a Pediatric Patient with isolated small intestinal transplant rescued with aggressive immunosuppressive approach

Introduction: Small intestinal transplantation has been the standard treatment modality for pediatric patient with intestinal failure who failed other surgical and medical treatment. At its current stage, it carries its own risks including but not limited to acute and chronic cellular rejection, graft malfunctions, development of PTLD, viral and bacterial infections. Acute cellular rejection of the intestinal graft is an important and major complication secondary to its rich lymphatic supply. It is usually results from sub therapeutic immunosuppression or non-adherence to medical management. The current management includes modifying the immunosuppression to achieve therapeutic level. Late severe acute intestinal allograft rejection is associated with increased risks of sepsis, bleeding and in the majority of cases with graft loss that ends up in graft enterectomy. We present a case of a 20 year old patient who underwent isolated small bowel transplant for complete intestinal Hirschsprung Disease at age 7 years old, but due to medication non-adherence developed severe late-onset acute cellular rejection manifested by large ostomy OP, fever, weight loss. Underwent ileoscopy on presentation that showed complete loss of normal anatomical intestinal landmarks, bleeding, and ulcerated mucosa. Graft biopsies showed ulceration and granulation tissue with severe architectural distortion, and rare residual consistent with severe intestinal graft rejection. She initially received pulse doses of Intravenous corticosteroids and increased dose of tacrolimus without significant improvement. Her immunosuppression plan was escalated to include infliximab and finally had Antithymocyte globulin (ATG). Graft enterectomy option was entertained frequently during the treatment course; however clinical improvement was noted with evidence of histological improvement and salvage of the graft. The aggressive anti-rejection treatment was complicated with the development of monomorphic, plasmacytoma (PTLD) that was managed with modifying her immunosuppression. Now her graft function is maintained on tacrolimus, oral prednisone, and routine Remicade infusion. Conclusion: 1-Small bowel graft rejection is associated with increased morbidity and mortality, increased risks of sepsis, bleeding and graft loss. 2-We believe that prompt and aggressive immunosuppressive approach significantly increases the chance of rescuing small bowel transplant rejection.

Mixed Rejection: More Important Than Thought after Heart Transplantation

Purpose Mixed rejection is defined as the simultaneous presence of antibody-mediated rejection (AMR) and acute cellular rejection (ACR). Mild forms of AMR and ACR are often found together, but moderate to severe (≥2R) ACR and AMR (≥1) is far less prevalent. We sought to assess whether patients with moderate to severe ACR and AMR together have a greater mortality and/or incidence of cardiac allograft vasculopathy (CAV). Methods Between 1999 and 2012, we identified 13 heart transplant patients who developed first-year simultaneous ACR (≥2R) and AMR (≥1). Control groups including patients with either ACR (n=43) or AMR (n=40) alone. Endpoints included subsequent 5-year survival, subsequent 5-year freedom from non-fatal major adverse cardiac events (NF-MACE: myocardial infarction, new congestive heart failure, percutaneous coronary intervention, implantable cardioverter defibrillator/pacemaker implant, and stroke), and subsequent freedom from cardiac allograft vasculopathy as defined by ≥ 30% stenosis by angiography. Results Patients with mixed rejection compared to ACR and AMR alone had a significantly reduced subsequent 5-year survival (46.2% vs 69.8% and 80.0% respectfully%, p=0.010). Causes of death in the mixed rejection group (n=7) included rejection (3), multi-organ failure (1), trauma (1) and unknown causes (2). There was no significant difference in subsequent 5-year freedom from CAV or NF-MACE. Conclusion Patients with first-year mixed rejection have a significant mortality risk at 5-years. More aggressive immune therapy to treat both cellular and humoral activation pathways may be needed in this group. Larger patient numbers with mixed rejection are needed to confirm these findings. Mixed rejection is defined as the simultaneous presence of antibody-mediated rejection (AMR) and acute cellular rejection (ACR). Mild forms of AMR and ACR are often found together, but moderate to severe (≥2R) ACR and AMR (≥1) is far less prevalent. We sought to assess whether patients with moderate to severe ACR and AMR together have a greater mortality and/or incidence of cardiac allograft vasculopathy (CAV). Between 1999 and 2012, we identified 13 heart transplant patients who developed first-year simultaneous ACR (≥2R) and AMR (≥1). Control groups including patients with either ACR (n=43) or AMR (n=40) alone. Endpoints included subsequent 5-year survival, subsequent 5-year freedom from non-fatal major adverse cardiac events (NF-MACE: myocardial infarction, new congestive heart failure, percutaneous coronary intervention, implantable cardioverter defibrillator/pacemaker implant, and stroke), and subsequent freedom from cardiac allograft vasculopathy as defined by ≥ 30% stenosis by angiography. Patients with mixed rejection compared to ACR and AMR alone had a significantly reduced subsequent 5-year survival (46.2% vs 69.8% and 80.0% respectfully%, p=0.010). Causes of death in the mixed rejection group (n=7) included rejection (3), multi-organ failure (1), trauma (1) and unknown causes (2). There was no significant difference in subsequent 5-year freedom from CAV or NF-MACE. Patients with first-year mixed rejection have a significant mortality risk at 5-years. More aggressive immune therapy to treat both cellular and humoral activation pathways may be needed in this group. Larger patient numbers with mixed rejection are needed to confirm these findings.

Clinical Outcomes of Perioperative Desensitization in Orthotopic Heart Transplant Recipients

Purpose Transplantation of sensitized recipients is associated with suboptimal post-transplant outcomes. This study assessed the effects of a perioperative desensitization strategy in virtual crossmatch (VXM)-positive orthotopic heart transplant (OHT) recipients compared to a historical cohort of VXM-negative OHT recipients. Methods This single-center, retrospective study included OHT recipients from 2010-2018. VXM-positive patients received perioperative plasmapheresis, intravenous immunoglobulin (IVIg), and antithymocyte globulin (rATG). VXM-negative historical controls received either high-dose steroids or alemtuzumab induction. Maintenance immunosuppression consisted of tacrolimus, mycophenolate, and a steroid taper. The primary endpoint was graft survival at 12 months. Secondary endpoints included freedom from acute rejection and freedom from severe (i.e., grade ≥ 2) acute cellular rejection or antibody-mediated rejection at 12 months. Results Of 91 patients included, 7 received desensitization. Baseline demographics, disease etiology, and comorbid conditions were similar between groups. VXM-positive recipients received a median of 5.1 (4.8-5.3) mg/kg of rATG, 0.9 (0-1.2) g/kg of IVIg, and 6 (3-7) plasmapheresis sessions. Maintenance immunosuppression was similar at all time points. There was one graft loss, which occurred in the VXM-negative cohort at 70 days post-OHT. The median time to rejection was 44.5 (16.5-93.5) days in the VXM-negative group versus 46.5 (10-83) days in the VXM-positive group (p=0.76). There were no differences in any other rejection outcomes. Six VXM-positive recipients cleared donor-specific antibodies (DSA) by day 21 and all cleared DSA by day 60 (Figure 1). Conclusion These data suggest that transplantation of VXM-positive OHT recipients receiving perioperative desensitization is feasible without excess graft loss or acute rejection at 12 months. The rapid clearance and lack of DSA recurrence is promising for long-term outcomes.

Risk evaluation using gene expression screening to monitor for acute cellular rejection in heart transplant recipients.

Gene expression profiling (GEP) was developed for non-invasive surveillance of acute cellular rejection. Despite its widespread use, there has been a paucity in outcome data for patients managed with GEP outside of clinical trials. The Outcomes AlloMap Registry (OAR) is an observational, prospective, multicenter study including patients aged ≥ 15 years and ≥ 55 days post-cardiac transplant. Primary outcome was death and a composite outcome of hemodynamically significant rejection, graft dysfunction, retransplantation, or death. Secondary outcomes included readmission rates and development of coronary allograft vasculopathy and malignancies. The study included 1,504 patients, who were predominantly Caucasian (69%), male (74%), and aged 54.1 ± 12.9 years. The prevalence of moderate to severe acute cellular rejection (≥2R) was 2.0% from 2 to 6 months and 2.2% after 6 months. In the OAR there was no association between higher GEP scores and coronary allograft vasculopathy (p = 0.25), cancer (p = 0.16), or non-cytomegalovirus infection (p = 0.10). Survival at 1, 2, and 5 years post-transplant was 99%, 98%, and 94%, respectively. The composite outcome occurred in 103 patients during the follow-up period. GEP scores in dual-organ recipients (heart-kidney and heart-liver) were comparable to heart-alone recipients. This registry comprises the largest contemporary cohort of patients undergoing GEP for surveillance. Among patients selected for GEP surveillance, survival is excellent, and rates of acute rejection, graft dysfunction, readmission, and death are low.

Paneth and Intestinal Stem Cells are Differentially Affected during Worsening of Acute Cellular Rejection in Small Bowel Transplantation compared to Intestinal Ischemia Reperfusion Injury and Graft versus Host Disease

Instituto de Estudios Inmunológicos y Fisiopatológicos, UNLP-CONICET, La Plata, Argentina. Introduction Acute cellular rejection (ACR) is one of the leading causes of graft loss after small bowel transplantation (SBTx). Although crypt epithelial cell apoptosis is used as histopathological criteria for ACR diagnosis, it is not clear which of epithelial lineages are the target of ACR. It was shown that the number of enteroendocrine progenitor cells in intestinal crypts was reduced during mild ACR, however, no results on other cell types of the crypt have been depicted so far. The aim of our work was to elucidate integrity and functionality of Paneth and stem cells during different degrees of ACR, in comparison with other clinical conditions such as graft vs. host disease (GVHD) and ischemia reperfusion injury (IRI). Material and Methods 44 patients of SBTx and controls treated in our center between 2006 and 2016 were included in the study. Rejection diagnosis was established by an experienced pathologist according to the recommendations of the pathology workshop of the VIII Small Bowel Transplantation Symposium. We compared small biopsies from SBTx patients with no, mild, moderate or severe ACR by immunohistochemistry and quantitative PCR (n=10 per group as average) for different cell markers (Lgr5, lysozyme, defensin5, IL22R, Ki67). Other conditions such as different degree of intestinal GVHD and IRI were included as separate groups. Comparisons among groups of data were performed with the Kruskal-Wallis test and the Dunn`s post-test when more than two groups were analyzed, whereas the Mann-Whitney U test was chosen to compare data from two groups. Results and Discussion Using differential immunofluorescence counting of different markers we observed that numbers of Paneth and stem cells remain constant in all ACR groups, whereas the transit-amplifying zone is the region that concentrates most of the apoptotic bodies during ACR (p<0.05). We detected unchanged level of antimicrobial peptides in Paneth cells and similar numbers of Ki-67+IL-22R+ stem cells revealing cell functionality in moderate ACR samples. Oppositely, in GVHD of moderate to severe, as well as IRI, Paneth cell number and markers were diminished (p<0.05), indicating differential mechanism that operate to trigger epithelial cell apoptosis in different situations. Conclusion Paneth and stem cells are not primary target cells during ACR. IL-22R + Ki-67+ stem cells might be an interesting target cell population for protection and regeneration of the epithelial monolayer during/after a severe ACR in ITx patients.

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

BackgroundTransient 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. MethodsThe Cochrane Library, Embase, and Medline PubMed databases were searched and updated to November 2016. The MESH terms used were “Liver Transplantation,” “Graft Rejection,” “Elasticity Imaging Techniques” (PubMed), and “Elastography” (Cochrane and Embase). ResultsSeventy studies were retrieved and selected using the PICO (patient, intervention, comparison or control, outcome) criteria. Three prospective studies were selected to meta-analysis and evaluation. A total of 33 patients with ACR were assessed with TE. One study showed a cutoff point of >7.9 kPa to define graft damage and <5.3 kPa to exclude graft damage (receiver operating characteristic 0.93; P < .001). Another study showed elevated levels of liver stiffness in ACR patients. However, in this study, no cutoff point for ACR was suggested. The final prospective study included 27 patients with ACR at liver biopsy. Cutoff points were defined as TE > 8.5 kPa, moderate to severe ACR, with a specificity of 100% and receiver operating characteristic curve of 0.924. The measurement of TE < 4.2 kPa excludes the possibility of any ACR (P = .02). ConclusionsTE may be an important tool for the severity of ACR in patients following liver transplantation. Further studies should be performed to better define the cutoff points and applicability of the exam.

The endoscopic surveillance of the transplanted small intestine: a single center experience and a proposal for a grading score

Objective: Microscopic examination of endoscopic biopsies forms the basis of acute cellular rejection (ACR) monitoring after intestinal transplantation (ITx). The endoscopy findings during acute rejection (AR) are known but a grading system for its severity is lacking. We designed and implemented a five-stage grading score based on acknowledged endoscopic features of AR, to allow a faster preliminary diagnosis of AR and intra- and interpatient comparisons.Methods: Two investigators reviewed and graded the endoscopy reports after 28 ITx using a novel score and correlated the results with pathology findings.Results: We reviewed 512 ileoscopies: 370 examinations (74%) were normal (G0), 59 had mild alterations (erythema, edematous villi-G1) and 36 showed moderate changes (erosions, blunted villi-G2); 17 ileoscopies revealed advanced changes (ulcerations, villus loss-G3). In 18 endoscopies the changes were severe (mucosal loss-G4). Inter-reviewer agreement was very good (kappa = 0.81). Biopsies from 86 endoscopy sessions (17%) indicated ACR with 63 cases having moderate or severe ACR. For mild ACR the sensitivity of the score was 29% and the specificity was 86% whereas the positive (PPV) and negative predictive values (NPVs) were 14% and 93% respectively. During advanced ACR the sensitivity and specificity were 92% and 86%, respectively whereas the PPV and NPV were 49% and 98% respectively.Conclusions: Endoscopy alone has a limited ability to reliably diagnose intestinal ACR. We suggest a novel grading score summarizing ACR findings and allowing comparisons between intestinal graft endoscopies.

Paneth and intestinal stem cells preserve their functional integrity during worsening of acute cellular rejection in small bowel transplantation.

Graft survival after small bowel transplantation remains impaired due to acute cellular rejection (ACR), the leading cause of graft loss. Although it was shown that the number of enteroendocrine progenitor cells in intestinal crypts was reduced during mild ACR, no results of Paneth and intestinal stem cells localized at the crypt bottom have been shown so far. Therefore, we wanted to elucidate integrity and functionality of the Paneth and stem cells during different degrees of ACR, and to assess whether these cells are the primary targets of the rejection process. We compared biopsies from ITx patients with no, mild, or moderate ACR by immunohistochemistry and quantitative PCR. Our results show that numbers of Paneth and stem cells remain constant in all study groups, whereas the transit-amplifying zone is the most impaired zone during ACR. We detected an unchanged level of antimicrobial peptides in Paneth cells and similar numbers of Ki-67+ IL-22R+ stem cells revealing cell functionality in moderate ACR samples. We conclude that Paneth and stem cells are not primary target cells during ACR. IL-22R+ Ki-67+ stem cells might be an interesting target cell population for protection and regeneration of the epithelial monolayer during/after a severe ACR in ITx patients.

Outcomes and Readmissions after Intestinal/Multivisceral Transplantation

Introduction: Intestinal (IT) and multivisceral (MVT) transplants are surgeries after which is not unusual to require multiple readmissions. Methods: Eleven intestinal transplants were performed in adults at Duke University Hospital during a 5year period and were followed until December 31,2016. Three were IT; the rest were MVT (small bowel, liver and pancreas). Six patients went into transplant on parenteral nutrition (PN) for short gut syndrome (SGS). One of them had desmoid tumors and served as a domino liver donor. The rest had cirrhosis and extensive portomesenteric thrombosis. Nine patients got induction with antithymocyte globulin (ATG); two with basiliximab. Results: All of the patients were discharged except for one who expired 31 days after transplant. The mean length of stay (LOS) was 40.4 days - 24.3 days for IT and 47.2 days for MVT. Thirty percent of the patients were discharged on PN and 60% on tube feeds. A LOS of 45 days or longer was associated with need of PN at discharge (p 0.011). Eight patients had acute cellular rejection (ACR). Two of them (IT) were severe; the rest were mild/moderate. The first readmission was within the first month of discharge in all patients except for one. The number of readmissions per patient was between 4 and 43 (total 131; mean 13.1; median 10.5). The LOS was between 1 and 69 days (mean 7.6 days). The total number of admissions within a year of transplant was 80 for all patients. Average LOS 58 days. The readmissions were: non-elective (111), elective (20), non serious (103), serious (28) (bacteremia, CMV viremia/enteritis, severe ACR, non-elective intra-abdominal surgery and abscesses, PRES, death). Admissions were also categorized per cause (table 2). Three patients died; two had IT. Causes of death were: aortic bleed from mycotic aneurysm; disseminated aspergillosis; severe ACR, MAC infection. Time between transplant and death was 31, 162, 471 days respectively.FigureFigureFigureConclusions: The majority of readmissions were in the first year after transplant. The majority were non-elective and non-life-threatening. Most common causes were infections and gastrointestinal symptoms. Beyond the first year of transplant, the number of readmissions and LOS of each one declined, with most patients either not having any or a single brief hospitalization. In comparison with the standard of care alternative therapy being PN, long term complications and need for hospitalization beyond the first year are similar.

Depletion Resistant Effector Memory T Cells Mediate Thymoglobulin Refractory Allograft Rejection in Human Intestinal Transplant Recipients

A: Intestinal transplantation (ITx) patients are disproportionally riddled with immune complications in comparison to less immunogeneic transplanted organs. Despite advances, severe acute cellular rejection (ACR) remains a critical source of morbidity and mortality. The gold standard treatment of severe ACR is with Thymoglobulin (Thy) T cell depletion therapy. The response rate to depletion is conventionally monitored by CD3 levels in peripheral blood. However, a significant number of ACR patients fail to clinically respond to Thy. This study aimed to determine the mechanisms underlying Thy resistant allograft rejection. B: A cohort of 21 out of a total 207 ITx patients, with histologically confirmed severe Grade III ACR was identified from the Georgetown Transplant Institute Tissue Bank Study. Immunomonitoring was accomplished by immunohistochemistry (IHC) and polychromatic flow cytometry (PFC). Clinical non-responders were defined as patients in rejection refractory to treatment or re-rejection within 90 days. C: Serial histological analysis of peripheral blood was performed on 12 clinical responders and 9 non-responders. Surprisingly, peripheral CD3 populations appeared uniformly depleted in both responders and non-responders (3.58% vs. 2.33%, p=0.488). This indicated that monitoring CD3 in peripheral blood is not reliable. We hypothesized that Thy-resistant allograft rejection is modulated by depletion resistant T cells in the allograft itself. Longitudinal IHC analysis of rejecting allografts confirmed that the degree of allograft T cell depletion correlated with clinical responsiveness. Specifically, 70% T cell depletion was found in responders to Thy treatment versus only 40% in non-responders (p<0.03). Next, to precisely characterize the depletion resistant cell phenotypes in the allograft, patients with ongoing severe ACR were prospectively immunomonitored with PFC. The vast majority of depletion resistant CD4+and CD8+ cell populations demonstrated more than 90% presence of CD45RO4+ effector memory T cells (TEM) phenotype, which have been implicated in other solid organ transplant rejections. D: This study demonstrates that T cell depletion immunomonitoring in the allograft is clinically superior to peripheral blood during treatment of ACR with Thy in human ITx patients. Phenotype analysis suggests that TEMs are critical effector cells in Thy depletion resistant ACR, which may have implications for the design of novel clinical treatment strategies. Karen Creswell, PhD.

Vedolizumab for the Treatment of Refractory Severe Rejection in Intestinal Transplantation

Introduction: Acute cellular rejection (ACR) is a continuous challenge in intestinal transplantation despite the advent of potent immunosuppressive drugs. Most of the traditional drugs used to treat ACR destroy specific cell lines with important systemic side effects. Migration of the activated recipient lymphocytes (T Cells) to the mucosal surface can trigger ACR in intestinal transplant. It has been demonstrated in a murine model of intestinal transplantation that during ACR allografts are infiltrate by large numbers of α4β7 T cells and the treatment with a blocking antibody specific for β7 significantly reduces the cellular infiltrate and inhibits ACR.[1] Vedolizumab is a humanized monoclonal antibody that binds specifically to the α4β7 integrin, inhibiting T lymphocytes from binding to adhesion molecules (MAdCAM-1), which are expressed mainly in the small bowel and colon. Consequently, vedolizumab can be considered a specific intestinal immunosuppressant, making it especially attractive in intestinal transplantion. Vedolizumab could provide specific down-modulation of the mucosal inflammatory response that is characteristic of IBD and allograft intestinal rejection, thereby allowing re-establishment of homeostasis in the intestinal immune system. Methods: Our group is reporting, to the best of our knowledge, the first report of using Vedolizumab for the treatment of severe ACR in intestinal transplantation. Results: 25 years old, female, with history of Crohn’s disease received an intestinal and colon transplant. After 6 months of follow up patient started missing clinical appointments and presenting undetectable immunosuppressant levels. Eleven months after the transplant patient presented to the ER critically ill. Scope with biopsy was performed showing severely inflamed mucosa, absence of villi, diffuse bleeding and ulcers. All the viral studies were negative. Alemtuzumab 30 mg X 2, Rituximab and steroids were given. After 2 weeks without improvement of symptoms another endoscopic evaluation was performed. Areas of moderate to severe erythematous mucosa without villi, severe friability and active bleeding was found. Patient was over-immunosuppressed and we opted to treat with Vedolizumab (x3). After 10 days from the first dose, a new scope was performed showing regeneration of villi, improved friability and no active bleeding. New scopes showed continuosly improvement of the mucosa followed by resolution of symptoms. PN was weaned and patient was discharged without parenteral support. Conclusions: Vedolizumab was successfully used to rescue a patient with severe rejection after failure of other therapies. It acts specifically in the intestinal mucosa with a much safer side-effect profile. More studies are necessary but it may become an excellent choice to treat or prevent rejection in intestinal transplantation. Reference: 1. Kellersmann R, et al. Monoclonal antibody against beta7 integrins, but not beta7 deficiency, attenuates intestinal allograft rejection in mice. Transplantation 2002 Nov 15;74(9):1327–34

Severe acute cellular rejection after intestinal transplantation is associated with poor patient and graft survival.

Severe acute cellular rejection (ACR) occurs frequently after intestinal transplantation (ITx). To evaluate the outcomes and the risk factors for graft failure and mortality in patients with severe ACR after ITx. Retrospective study evaluating all ITx recipients who developed severe ACR between 01/2000 and 07/2014. Demographic and histologic data were reviewed. 20/126 (15.9%) ITx recipients developed severe ACR. Of these 20 episodes, 13 were in adults (median age: 47.1). The median (IQR) time from ITx to severe ACR was 206.5 (849) days. All patients received intravenous methylprednisolone and increased doses of tacrolimus. Sixteen (80%) patients did not respond to initial treatment and required thymoglobulin administration. Moreover, 11 (55%) patients required additional immunosuppressive medications. Six (30%) patients required graft enterectomy. Complications related to ACR treatment were the following: 10 (50%) patients developed bacterial infections, four (20%) patients developed cytomegalovirus infection and four (20%) patients developed post-transplant lymphoproliferative disease. At the end of follow-up, only 3/20 (15%) were alive with a functional allograft. The median patient survival time after diagnosis of severe ACR was 400days (95% CI: 234.0-2613.0). Severe ACR episodes are associated with high rates of graft loss and complications related to treatment.

Noninvasive monitoring of acute and chronic rejection in heart transplantation.

Recent years have seen advances in the early detection of cardiac graft rejection. We review the possibilities offered by tissue Doppler imaging and speckle tracking echocardiography, cardiac magnetic resonance, cardiac computed tomography, single positron emission tomography, gene expression profiling, and quantitation of donor-derived cell-free DNA, and microRNAs. Noninvasive monitoring of acute and chronic rejection after cardiac transplantation is an unmet need and remains a challenge. Imaging techniques and peripheral blood biomarkers are the most commonly used approaches, and in recent years there has been great progress. Gene expression profiling seems to be useful for ruling out the presence of a moderate to severe acute cellular rejection in stable, low-risk patients. Newer monitoring tools, like donor-derived cell-free DNA or microRNA, seem to be promising for individualizing immunosuppressive therapies and better understanding the mechanisms of rejection.

Association of the Number of HLA-DR Mismatches With Early Post-transplant Acute Cellular Rejection Among Heart Transplantation Recipients: A Cohort Study in Japanese Population

BackgroundAlthough many risk factors are reported about graft rejection after heart transplantation (HTx), the effect of HLA mismatch (MM) still remains unknown, especially in the Japanese population. The aim of the present study was to investigate the influence of HLA MM on graft rejection among HTx recipients in Japan. MethodsWe retrospectively investigated the association of the number of HLA MM including class I (A, B) and class II (DR) (for each locus MM: 0 to 2, total MM: 0 to 6) and the incidence of moderate to severe acute cellular rejection (ACR) confirmed by endomyocardial biopsy (International Society for Heart and Lung Transplantation grade ≥ 3A/2R) within 1 year after HTx. ResultsBetween 2007 and 2014, we had 49 HTx cases in our institute. After excluding those with insufficient data and positive donor-specific antigen, finally 35 patients were enrolled. Moderate to severe ACR was observed in 16 (45.7%) patients. The number of HLA-DR MM was significantly associated with the development of ACR (ACR+: 1.50 ± 0.63, ACR−: 1.11 ± 0.46, P = .029). From univariate analysis, DR MM = 2 was the only independent risk factor for ACR episodes (P = .017). The frequency of ACR within 1 year was significantly higher in those with DR MM = 2 (DR MM = 0 to 1: 0.3 ± 0.47, DR MM = 2: 1.17 ± 1.34 times, P = .007). ConclusionsThe number of HLA-DR MMs was associated with the development and recurrence of ACR episodes among HTx recipients within 1 year after transplantation in Japanese population.