Acute Cellular Rejection Group Research Articles

Usefulness of Diffusion-Weighted Imaging in Evaluating Acute Cellular Rejection and Monitoring Treatment Response in Liver Transplant Recipients.

Acute cellular rejection (ACR) is a significant immune issue among recipients following liver transplantation. Although diffusion-weighted magnetic resonance imaging (DWI) is widely used for diagnosing liver disease, it has not yet been utilized for monitoring ACR in patients after liver transplantation. Therefore, the aim of this study was to evaluate the efficacy of DWI in monitoring treatment response among recipients with ACR. This study enrolled 25 recipients with highly suspected ACR rejection, and all subjects underwent both biochemistry and DWI scans before and after treatment. A pathological biopsy was performed 4 to 24 h after the first MRI examination to confirm ACR and degree of rejection. All patients were followed up and underwent a repeated MRI scan when their liver function returned to the normal range. After data acquisition, the DWI data were post-processed to obtain the apparent diffusion coefficient (ADC) map on a voxel-by-voxel basis. Five regions of interest were identified on the liver parenchyma to measure the mean ADC values from each patient. Finally, the mean ADC values and biochemical markers were statistically compared between ACR and non-ACR groups. A receiver operating characteristic (ROC) curve was constructed to evaluate the performance of the ADC and biochemical data in detecting ACR, and correlation analysis was used to understand the relationship between the ADC values, biochemical markers, and the degree of rejection. The histopathologic results revealed that 20 recipients had ACR, including 10 mild, 9 moderate, and 1 severe rejection. The results demonstrated that the ACR patients had significantly lower hepatic ADC values than those in patients without ACR. After treatment, the hepatic ADC values in ACR patients significantly increased to levels similar to those in non-ACR patients with treatment. The ROC analysis showed that the sensitivity and specificity for detecting ACR were 80% and 95%, respectively. Furthermore, the correlation analysis revealed that the mean ADC value and alanine aminotransferase level had strong and moderate negative correlation with the degree of rejection, respectively (r = -0.72 and -0.47). The ADC values were useful for detecting hepatic ACR and monitoring treatment response after immunosuppressive therapy.

Center volume effect on acute cellular rejection and outcomes in pediatric lung transplant recipients

Acute cellular rejection (ACR) is common after lung transplant (LTx). We sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. The United Network for Organ Sharing (UNOS) Registry was queried for patients <18-years-of-age who underwent LTx 1987-2020. Cohorts were children who survived the first-year post transplant and were treated for ACR within that first year (ACR group) and those not treated for ACR (non-ACR). LTx center volume was defined as: high volume center (HVC) (>5LTxs/year), medium volume center (MVC) (>1≤5 LTxs/year), and low volume center (LVC) (≤1LTxs/year). 1320 patients were enrolled into the study; 269 (20.4%) did not experience ACR. The ACR cohort was older (median 14 [11-16] vs 13 [7-16] years, p<0.001), female (65.3% vs 57.3%, p=0.016), cystic fibrosis diagnosis (62.3% vs 45.5%, p<0.001), and higher lung allocation score (37.3 [34.6-47.8] vs 35.8 [33-42.6], p=0.029). The ACR cohort trended (p=0.06) towards lower survival at 5-year (37% vs 47%) and 10-year (25% vs 34%) post-LTx. Among children at HVCs, ACR occurred in 17% of recipients (n=98/574), compared to 18.5% (n=73/395) at MVCs and 27% (n=100/369) at LVCs. Children treated for ACR at HVCs had higher survival than LVCs at 5-years (52% vs 29%) and 10-years (36% vs 15%) (p<0.001) but similar survival to MVCs at 5-years (52% vs 43%) and 10-years (36% vs 24%) (p=0.081). No survival differences were detected in MVCs vs LVCs (p=0.14). ACR treated within the first post-LTx year influence survival of children. ACR incidence was lowest at higher volume centers whereas post-ACR treatment survival outcomes were also superior.

High Volume Centers Have Lower Incidence of Acute Cellular Rejection in Pediatric Lung Transplant Recipients and Better Survival After Treatment

Purpose Acute cellular rejection (ACR) is a common form of allograft rejection in pediatric recipients after lung transplant (LTx). ACR most commonly occurs during the 1st post-transplant year. This study sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. Methods The United Network for Organ Sharing (UNOS) Registry was queried for patients <18 years who underwent LTx in 1987-2020. Cohorts were patients who were treated for ACR during the 1st post-LTx year (ACR group) and who did not experience ACR (non-ACR). Survival of patients who had ACR was compared by LTx center volume defined as average of LTx/year: >5LTx/year (high), >1-≤5LTx/year (medium) and 1LTx/year (low). Results 1338 patients were included in our analysis with 271 (20.3%) identified as having ACR. Compared to non-ACR, the ACR cohort were older (median 14 [11-16] vs 13 [7-16] years, p<0.001), more commonly female (65.3% vs 57.3%, p=0.016), more commonly diagnosed with cystic fibrosis (62.3% vs 45.5%, p<0.001), and had a higher lung allocation score at LTx (37.3 [34.6-47.8] vs 35.8 [33-42.6], p=0.029). Kaplan-Meier survival of ACR vs non-ACR cohorts trended towards lower survival at 5-yr (37% vs 47%) & 10-yr (25% vs 34%) post-LTx, p=0.06. ACR occurred in 17% of patients at high (n=98/574), 18.5% (n=73/395) at medium, and 27% (n=100/369) at low volume centers. Patients treated for ACR at high volume centers had better post-transplant survival than low volume centers (p<0.001) but similar survival to those at medium volume centers (p=0.081; Figure). No significant difference in survival was observed in medium vs low volume centers (p=0.14). Conclusion ACR treated within the 1st post-LTx year influences survival of pediatric LTx recipients. ACR incidence was lowest at higher volume centers where post-ACR treatment survival outcomes were also superior. More analysis is needed to determine factors affecting differences in center outcomes regarding ACR. Acute cellular rejection (ACR) is a common form of allograft rejection in pediatric recipients after lung transplant (LTx). ACR most commonly occurs during the 1st post-transplant year. This study sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. The United Network for Organ Sharing (UNOS) Registry was queried for patients <18 years who underwent LTx in 1987-2020. Cohorts were patients who were treated for ACR during the 1st post-LTx year (ACR group) and who did not experience ACR (non-ACR). Survival of patients who had ACR was compared by LTx center volume defined as average of LTx/year: >5LTx/year (high), >1-≤5LTx/year (medium) and 1LTx/year (low). 1338 patients were included in our analysis with 271 (20.3%) identified as having ACR. Compared to non-ACR, the ACR cohort were older (median 14 [11-16] vs 13 [7-16] years, p<0.001), more commonly female (65.3% vs 57.3%, p=0.016), more commonly diagnosed with cystic fibrosis (62.3% vs 45.5%, p<0.001), and had a higher lung allocation score at LTx (37.3 [34.6-47.8] vs 35.8 [33-42.6], p=0.029). Kaplan-Meier survival of ACR vs non-ACR cohorts trended towards lower survival at 5-yr (37% vs 47%) & 10-yr (25% vs 34%) post-LTx, p=0.06. ACR occurred in 17% of patients at high (n=98/574), 18.5% (n=73/395) at medium, and 27% (n=100/369) at low volume centers. Patients treated for ACR at high volume centers had better post-transplant survival than low volume centers (p<0.001) but similar survival to those at medium volume centers (p=0.081; Figure). No significant difference in survival was observed in medium vs low volume centers (p=0.14). ACR treated within the 1st post-LTx year influences survival of pediatric LTx recipients. ACR incidence was lowest at higher volume centers where post-ACR treatment survival outcomes were also superior. More analysis is needed to determine factors affecting differences in center outcomes regarding ACR.

Novel left and right ventricular strain analysis to detect subclinical myocardial dysfunction in cardiac allograft rejection.

Early detection of acute cellular rejection (ACR) by echocardiography shows potential clinical benefit as ACR remains a significant contributor to morbidity and mortality. This retrospective, longitudinal study sought to investigate the use of novel left (LV) and right ventricular (RV) strain analysis to detect biopsy proven ACR. 46 heart transplant patients (Mean age 46 ± 16years) with biopsy proven ACR were grouped according to biopsy results: 1R-ACR (n = 36) and 2R-ACR (n = 10). Serial two-dimensional transthoracic echocardiography with strain analysis was performed. Echocardiographic parameters were serially measured: (1) rejection free period (0R-ACR); (2) pre-ACR period (pre-ACR); (3) during ACR (1R-ACR or 2R-ACR) and (4) post-ACR (Post-ACR). Significant reductions for LV Global Longitudinal Strain (LV GLS) and LV Early diastolic Strain rate (LV ESr) were observed between 0R-ACR and pre-ACR (LV GLS 0R-ACR: 17.3% vs Pre-2R ACR: 15.4%, p = 0.016; LV ESr 0R-ACR: 1.00/s vs Pre-2R ACR: 0.74/s, p = 0.007) with LV ESr demonstrating the highest sensitivity (92%) and specificity (81%) to predict ACR. LV ESr and the E/LV ESr ratio were significantly different (p = 0.0001; p = 0.016) during pre-1R ACR period vs 0R whereas LV GLS showed no significant differences for grade 1R-ACR. Diastolic mechanical dispersion showed significant increases in dispersion during ACR for the 1R-ACR group and early significant increases pre-2R ACR. Systolic and diastolic RV strain parameters showed a similar trend for both ACR groups. Systolic and diastolic strain parameters can detect myocardial dysfunction before biopsy confirmed 2R-ACR. Early diastolic strain rate parameters are most sensitive detecting subclinical myocardial dysfunction pre-ACR. Novel strain parameters are potentially useful clinical tool for prediction of early ACR in heart transplant.

Identification of High-Mobility Group Box 1 (HMGB1) Expression as a Potential Predictor of Rejection and Poor Prognosis After Liver Transplantation.

BackgroundAcute cellular rejection (ACR) frequently occurs after liver transplantation (LT) and can result in permanent damage of the liver allograft. Specific and sensitive biomarkers for predicting and monitoring ACR are vital for guiding post-transplantation care. In the present study, we aimed to investigate the function of high-mobility group box 1 (HMGB1) in predicting ACR and prognosis after LT.Material/MethodsA total of 113 LT recipients were enrolled in the study, including 62 patients in an ACR group and 51 patients in a non-rejection group. Using tissues from the 113 patients, HMGB1 expression was examined by immunohistochemistry, and the total score for HMGB1 expression was calculated by multiplying the percentage of immunoreactive cells score and the staining intensity score. We then analyzed the association between HMGB1 expression and clinical features. Finally, the function of HMGB1 in predicting the prognosis of LT was determined using Kaplan-Meier (K-M) survival and Cox multivariate analyses.ResultsImmunohistochemical staining results demonstrated that the expression of HMGB1 was significantly increased in the ACR group, compared with that in the non-rejection group (P<0.05). Clinical characteristic analysis revealed that high HMGB1 levels were related to ACR (P<0.05). Moreover, K-M survival analysis showed that patients with high HMGB1 expression displayed poorer prognosis (P<0.05). Cox multivariate analysis demonstrated that HMGB1 was an independent prognostic predictor for post-LT survival (odds ratio, 3.283; P=0.008).ConclusionsLT recipients’ HMGB1 levels may be a useful and noninvasive biomarker for the prediction of ACR and prognosis after LT.

Circulating miR-181a-5p as a new biomarker for acute cellular rejection in heart transplantation

Acute cellular rejection (ACR) is a major complication in heart transplantation (HTx). Endomyocardial biopsy is the reference method for early detection of ACR, but a new non-invasive approach is needed. Tentative candidates could be circulating microRNAs. This study aimed to discover and validate microRNAs in serum for ACR detection after HTx. This prospective, observational, single-center study included 121 HTx patients. ACR was graded according to International Society of Heart and Lung Transplantation classification (0R-3R). First, in the discovery phase, microRNA expression profile was carried out in serum samples from patients at pre-rejection, during, and post-rejection time (0RS1 → 2RS2` → 0RS3). Relative expression (2-∆Cq) of 179 microRNAs per sample was analyzed by reverse transcription quantitative polymerase chain reaction. Second, a microRNA with a significant rise and fall pattern during ACR was selected for the next validation phase, where it was analyzed (reverse transcription quantitative polymerase chain reaction) in serum samples from 2 groups of patients: the no-ACR group (0R grade) and the ACR group (≥2R grade). Finally, a sensitivity analysis (receiver operating characteristic curve) was done to assess microRNA accuracy for ACR detection in HTx. A total of 21 ACR episodes (0RS1 → 2RS2 → 0RS3) with their respective serum samples (n = 63) were included in the discovery phase. Among the 179 microRNAs analyzed, only miR-181a-5p met the rise and fall criteria. In the validation phase, miR-181a-5p relative expression (2-∆Cq) in the ACR group (n = 45) was significantly overexpressed (p < 0.0001) vs the no-ACR group (n = 45). miR-181a-5p showed an area under the curve of 0.804 (95% confidence interval: 0.707-0.880); sensitivity and specificity of 78% and 76%, respectively; and a negative predicted value of 98%. miR-185a-5p in serum is a candidate as a non-invasive ACR biomarker (area under the curve = 0.80 and negative predicted value = 98%). Thus, this biomarker could reduce the need for endomyocardial biopsies and the associated risks and costs of this invasive procedure.

Faster Time-to-Therapeutic Tacrolimus Level is Associated with Lower Risk of Cellular Rejection Early after Heart Transplantation

Faster time-to-therapeutic tacrolimus (TTT) levels is associated with lower rates of acute cellular rejection (ACR) in kidney and liver transplantation. Limited data have evaluated this relationship in heart transplant (HT) recipients. Single-center retrospective chart review of patients who received HT from January 1, 2014 to June 30, 2016. Multi-organ transplant recipients, re-transplants, and those who received induction therapy with either basiliximab or thymoglobulin were excluded. A therapeutic tacrolimus concentration was defined as a trough level between 8-15 ng/mL for two consecutive days. The primary outcome was the rates of 30-day ACR in patients who were < and ≥ the median TTT level. Serum creatinine values were also collected for the first 10 post-op days. From a database of 88 HT patients we evaluated 55 patients who did not receive induction therapy (median age=56 (49-65), 73% white, 71% had a VAD prior to HT). The median TTT level was 9 days; patients < the median (n=25) had similar characteristics as those ≥ the median (n=30). Rates of ACR were significantly lower in the < median group (8 v. 43%, p=0.005) (Figure), while serum creatinine values were similar between groups (p>0.05 for each day). Patients without ACR (n=40) had a median TTT level of 8 (6-9.5) days, compared to 10 (9-12) days in the ACR group (n=15) (p=0.01). A multivariate regression model found TTT ≥9 days to be significantly associated with early ACR after adjusting for age, gender, and VAD pre-HT (OR 9.84, 95% CI [1.86-52.90], p=0.007). Quickly achieving a TTT level reduces the risk of ACR early after HT without adversely affecting renal function.

Plasma Induced Transcriptional Analysis Assessment of Rejection in Pediatric Heart Transplantation

Graft rejection after heart transplantation (HT) is a key clinical issue. The diagnostic gold standard of cardiac catheterization with myocardial biopsies is an invasive procedure that may underdiagnose rejection. A possible novel noninvasive alternative is using plasma to perform transcriptional analysis (TA) to assess gene expression levels associated with rejection. Studies on TA in pediatric HT are lacking. This study aimed to investigate plasma induced TA as an assessment of acute cellular rejection (ACR) in pediatric HT. Plasma collected from 25 pediatric HT recipients at the time of catheterization was used to induce a transcriptional response, measured by Affymetrix U133+2.0 array, in commercially available peripheral blood mononuclear cells. Additional data collected included age, gender, time since transplant (TST), cardiac index (CI), right ventricular end diastolic pressure (RVEDP), wedge pressure (WP), echo ejection fraction (EF), and NT Pro BNP. Subjects with ACR (defined as grade ≥ 1R on biopsy) were compared to those with no rejection (NR). 10 patients had ACR and 15 had NR. There were no significant differences between ACR and NR in age (8.5 vs 9.3 years, p=0.76), gender (60% vs 53% male, p=0.74), TST (3.4 vs 3.7 years, p=0.75), CI (3.8 vs 3.2 L/min/m2, p=0.08), RVEDP (7.8 vs 7.3 mmHg, p=0.77), WP (11.6 vs 10.5 mmHg, p=0.39), EF (65% vs 66%, p=0.49), and NT Pro BNP (831 vs 1083 pg/mL, p=0.67), respectively. Between ACR and NR, TA revealed 494 unique probesets with a false discovery rate of ≤10% (Figure 1). Genes associated with T-cell activation and migration were upregulated in the ACR group. These included CX3CR1, TNFRSF13C, TNFAIP8, ITGA4, TRDC, IL6ST, IL23A, and CD84. TA produced signatures specific to ACR in pediatric HT recipients. The identified genes were consistent with current understanding of ACR. TA can shed insight into the mechanisms of rejection in pediatric HT recipients and should be investigated further as a noninvasive diagnostic tool.

Identification of HO-1 as a novel biomarker for graft acute cellular rejection and prognosis prediction after liver transplantation.

BackgroundLiver transplantation (LT) is the most effective treatment for patients with end-stage liver diseases, but acute rejection is still a major concern. However, the mechanisms underlying rejection remain unclear. Biomarkers are lacking for predicting rejection and long-term survival after LT.MethodsIsobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics was performed between acute cellular rejection (ACR) and non-rejection recipients. The molecular signature differences and potential biomarkers were identified by comprehensive bioinformatics. Heme oxygenase-1 (HO-1) expression and its association with clinical outcomes were investigated by tissue microarrays consisted of liver specimens from recipients with (n=80) and without ACR (n=57).ResultsA total of 287 differentially expressed proteins (DEPs) were identified. Pathway analysis revealed that T/B cell activation, integrin/inflammation signaling pathway, etc. were significantly correlated with ACR. Through comprehensive bioinformatics, HO-1 was identified as a candidate potential biomarker for ACR. In tissue microarray (TMA) analysis, HO-1 expression was significantly higher in ACR group than in non-rejection group (P<0.01). Preoperative Child-Pugh and Meld scores were significantly higher in recipients with high HO-1 expression (P<0.01). In a mean 5-year follow-up, recipients with high HO-1 expression were associated with a shorter overall survival (P<0.05). Further multivariate analyses indicated that HO-1 could be an independent adverse prognostic factor for post-transplant survival (P=0.005).ConclusionsA total of 287 DEPs were identified, providing a set of targets for further research. Recipients with high preoperative HO-1 expression were associated with ACR. HO-1 may be used as a potential biomarker for predicting the development of post-transplant allograft ACR and recipient’s survival.

Neutrophil-to-lymphocyte ratio predicts early acute cellular rejection in living donor liver transplantation.

PurposeThe aim of this study was to evaluate the predictive value of neutrophil-to-lymphocyte ratio (NLR) in acute cellular rejection (ACR) after living donor liver transplantation (LDLT).MethodsAll consecutive patients who underwent ABO-compatible (ABOc) LDLT from September 2014 to December 2017 were retrospectively reviewed. NLR was calculated on 3 occasions; (1) 4 weeks prior to liver transplantation (LT), (2) the day of LT, and (3) the day before liver biopsy.ResultsAmong 66 patients who underwent ABOc LDLT, ACR was identified in 15 patients (22.7%) on protocol liver biopsy performed routinely on the postoperative day 7. There was no significant difference in NLR at 4 weeks prior to LT and the day of LT between no-ACR and ACR group (2.98 ± 1.92 vs. 2.54 ± 1.15, P = 0.433; 17.9 ± 8.31 vs. 20.5 ± 13.4, P = 0.393). However, NLR was significantly lower in ACR group compared to non-ACR group just prior to liver biopsy (5.82 ± 3.42 vs. 18.4 ± 17.2, P = 0.035). NLR tends to decrease 3.5 days before the onset of ACR. The area under the receiver operating characteristic curve for optimal cut-off value of NLR was 6.49, with sensitivity and specificity of 80.4% and 73.3% respectively.ConclusionNLR has a potential as a noninvasive predictor of early ACR in ABOc LDLT.

Effectiveness of Perioperative Immunologic Markers Monitoring for Predicting Early Acute Cellular Rejection After Living Donor Liver Transplantation

BackgroundThe objective of this study was to determine whether perioperative immunologic markers monitoring could predict early acute cellular rejection (ACR) after living donor liver transplantation (LDLT). Materials and methodsFrom September 2010 to June 2013, a total of 172 patients underwent LDLT at our transplant center. Of them, 26 patients were excluded because of infection. We retrospectively reviewed the remaining 146 patients. CD4 lymphocyte activity, T cell subsets test, and serum cytokine panel were checked on the day before transplantation and at 20 days after transplantation. These patients were divided into 3 groups: 1. normal liver function test (LFT) group; 2. increased LFT without rejection group; and 3. early ACR group. We excluded the increased LFT without rejection group in order to rule out multiple factors influencing immunologic factors. ResultsCD4 lymphocyte activity (P = .004) was significantly increased while CD4+/CD25+/FOXP3+ cells (P < .001) and interleukin (IL)-17 (P = .002) levels were significantly decreased during the perioperative period. Pretransplant IL-6 (P = .014) and IL-17 (P = .029) levels in the early ACR group were significantly lower than those in the normal LFT group. The proportion of patients with increased IL-6 during perioperative period in the early ACR group was higher than that in the normal LFT group, although the difference was not statistically significant (P = .065). ConclusionOur results suggest that IL-6 and IL-17 levels are associated with early ACR in LDLT patients. However, whether monitoring perioperative immunologic markers could predict early ACR remains unclear. Further prospective studies are needed to reach a definite conclusion.

Exosome-derived galectin-9 may be a novel predictor of rejection and prognosis after liver transplantation.

Acute cellular rejection (ACR) remains a major concern after liver transplantation. Predicting and monitoring acute rejection by non-invasive methods are very important for guiding the use of immunosuppressive drugs. Many studies have shown that exosomes and their contents are potential biomarkers for various liver diseases. Here, we identify and validate the role of exosomes and galectin-9 in ACR after liver transplantation. Exosomes were isolated from three sets of paired patients, with and without ACR, and the proteins within the exosomes were isolated and identified. Candidate proteins were then validated using a tissue microarray containing resected liver samples from 73 ACR and 63 non-rejection patients. Finally, protein expression and clinical manifestations were included in Kaplan-Meier survival and Cox regression analyses. Circulating exosomes were isolated from ACR and non-rejection patients and characterized using transmission electron microscopy and western blotting for CD63/CD81. Western blotting experiments revealed higher levels of galectin-9 protein in circulating exosomes from ACR recipients. Immunohistochemical analysis of the tissue microarray showed that the expression of galectin-9 in resected liver was significantly higher in the ACR group than in the non-rejection group (P<0.05). Higher levels of galectin-9 expression in resected livers were associated with poorer prognosis (P<0.05). Exosome-derived galectin-9 may be a novel predictor of rejection and prognosis after liver transplantation.

ITRAQ-based quantitative proteomic analysis reveals potential early diagnostic markers in serum of acute cellular rejection after liver transplantation

Liver transplantation (LT) is the most effective treatment method for advanced stage liver disease but acute cellular rejection (ACR) seriously affects the prognosis of LT. To discover novel diagnostic biomarkers of ACR after LT, Isobaric Tags for Relative and Absolute Quantitation (iTRAQ)-based mass spectrometry was performed to characterize alterations of serum proteins among patients validated to be pathologically ACR or pathologically no-ACR after LT and healthy controls. As a result, 10 differentially expressed proteins were found out between the ACR group and the No-ACR group; 88 differentially expressed proteins were found out between the ACR group and the Healthy Control group; 39 differentially expressed proteins were found out between No-ACR group and Healthy Control group. After analysis and ELISA validation, the results showed that CFHR1, CFHR5 and CFH could be candidate protein biomarkers for the early diagnosis of ACR after LT.

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.

Speckle-Tracking Echocardiography for Monitoring Acute Rejection in Transplanted Heart

BackgroundThe diagnosis of acute cellular rejection (ACR) is a major objective in the management of heart transplant recipients. The aim of this study was to assess the utility of speckle-tracking derived parameters in identifying patients at risk of graft rejection. MethodsA prospective, single-center study was carried out involving 45 consecutive heart transplant patients who underwent a total of 220 routine endomyocardial biopsies (EMBs) with correlative echocardiographic examination. ResultsNo significant ACR (grade 0-1R) was seen in 190 biopsies (81.2% of the ACR-free group), and moderate ACR requiring specific treatment (grade 2R) was detected in 30 biopsies (13.6% of the ACR group). Grade 3R was not observed. All longitudinal left ventricular (LV) and right ventricular (RV) strain parameters were greater in the ACR-free group than in patients with ACR, while no differences were observed between radial and circumferential strain parameters. In our analysis, we selected RV free wall longitudinal strain (RV FW) ≤ 16.8% and 4-chamber longitudinal strain (4CH LS) ≤ 13.8%, which related to the presence of ACR requiring treatment. We assigned 1 point for each parameter (minimum 0, maximum 2 points) and derived a new echocardiographic index, the Strain Rejection Score (SRS). Our proposed approach—a combination of the 2 abovementioned indices—for screening patients at risk of ACR ≥ 2R, when expressed by a score 2 points, showed good specificity, strong negative predictive value, and the highest area under the curve. ConclusionsOur study demonstrated that combination of 4CH LS and RV FW as a new echocardiographic index, the Strain Rejection Score, can be useful as a noninvasive assessment of ACR during the first year of follow-up after heart transplant.

Down regulation of protective genes is associated with cellular and antibody-mediated rejection.

A total of 300 formalin-fixed and paraffin-embedded (FFPE) endomyocardial biopsies sampled from 63 heart allograft recipients were included in this study. Acute cellular rejection (ACR) and antibody-mediated rejection (AMR) were diagnosed by histological analysis and immunohistochemical C4d staining, respectively. Analysis of gene expression was performed by quantitative real-time polymerase chain reaction. The samples were grouped according to the ISHLT rejection classification, aiming the statistical analysis. There was a significant decrease in the HMOX1, AIF1, and CCL2 transcript over the post-transplantation period in non-rejection group (P<.001). Furthermore, the ADIPOR1, ADIPOR2, BCL2L1, and VEGFA protective genes were significantly downregulated in the ACR group (P<.05). ADIPOR2, BCL2L1, IL6, and NOS2 genes were also significantly downregulated in the AMR group than in the non-rejection group (P<.05). The downregulations of the protective genes contribute to the allograft rejection, and the archived FFPE samples are useful for the gene expression analysis aiming the allograft rejection surveillance.

Acute Cellular Rejection in ABO-Incompatible Renal Transplant Recipients Receiving Rituximab Is Associated with Delayed-Onset Neutropenia.

BACKGROUND Rituximab induces long-lasting B cell depletion in the peripheral blood and increases the levels of proinflammatory cytokines associated with regulatory B cell depletion. Previous reports showed that B cell-related cytokine release after administration of rituximab may induce acute cellular rejection (ACR) and delayed-onset neutropenia. The present study was conducted to investigate the correlation between acute rejection and delayed-onset neutropenia in ABO-incompatible renal transplant recipients who underwent administration of rituximab for 1 year after transplantation. MATERIAL AND METHODS From June 2006 to July 2015, 47 patients with chronic renal failure received ABO-incompatible renal transplant with rituximab induction at Osaka City University Hospital. All 47 patients underwent plasmapheresis due to removal of anti-A/B antibodies and administration of rituximab, and their transplants were carried out successfully. We investigated the correlation between ACR and delayed-onset neutropenia in ABO-incompatible renal transplant recipients who underwent administration of rituximab for 1 year after transplantation. RESULTS Fourteen patients (29.8%) experienced ACR (group A), and 33 recipients did not develop ACR (group B). The frequency of delayed-onset neutropenia was higher in group A than in group B (p=0.0503). Multivariate logistic regression analysis revealed that the frequency of ACR correlated significantly with the prevalence of delayed-onset neutropenia. CONCLUSIONS Our results indicated that ACR in ABO-incompatible renal transplant recipients receiving rituximab was associated with delayed-onset neutropenia.

Serial changes in longitudinal graft function and implications of acute cellular graft rejections during the first year after heart transplantation.

The aim of this prospective study was to use left ventricular global longitudinal strain (LV-GLS) as a non-invasive tool for the monitoring of graft function in relation to acute cellular rejection (ACR) during the first year after heart transplantation (HTX). The study population consisted of 36 patients undergoing HTX from November 2010 until October 2013. Patients were followed by comprehensive echocardiography and biopsies at 2 weeks and 1, 3, 6, and 12 months after HTX. ACRs were classified based on the ISHLT classification (0R-3R). Patients were divided into two groups according to the presence of one or more episodes of biopsy proven ≥grade 2R ACR during follow-up. We found that LV-GLS and tricuspid annular plane systolic excursion (TAPSE) were significantly related to ACR burden in a linear regression model. The absolute difference in LV-GLS between patients in the ACR group (-14.4%) and patients in the ACR-free group (-16.8%) was -2.4% (P < 0.01) 12 months after HTX. In the ACR group, patients' LV-GLS did not improve between 1 and 12 months, whereas an improvement of -2.9% was seen in the ACR-free group in this period (P < 0.01). The two groups appeared not to differ in terms of diastolic Doppler parameters or LV ejection fraction, but TAPSE was 15.3 ± 2.8 mm in the ACR-free group vs. 13.2 ± 2.1 mm ACR group, P < 0.05, 12 months after HTX. Gradual improvement of longitudinal LV and RV function was seen within the first year after HTX, but the degree of recovery was strongly influenced by ACR episodes.

Clinical significance of intragraft miR-122 and -155 expression after liver transplantation.

Recurrent hepatitis C (RHC) and acute cellular rejection (AR) remain critical problems following liver transplantation (LT) in hepatitis C virus (HCV) positive recipients because of the similar clinical features. Discrimination between these conditions can be problematic, and adjunctive biomarkers would be useful to discriminate these processes. The aim of our study was to investigate the possibility of the intragraft miR-122 and -155 expression as new biomarkers after LT. A total of 29 HCV positive recipients were enrolled in this study. Intragraft expressions of miR-122 and -155 were studied between RHC predominant (n = 17) and AR predominant cases (n = 12) using quantitative reverse transcription polymerase chain reaction. Furthermore, we investigated the correlations between these expression levels and clinical serum parameters. Intragraft miR-122 expression had a good correlation with serum alkaline phosphatase (P = 0.02), but it was not correlated with the serum HCV viral load. The expression levels of miR-122 in the AR group were significantly higher than those in the RHC group (P = 0.0006) and, inversely, the expression levels of miR-155 in the AR group were significantly lower than those in the RHC group (P = 0.01). Our study emphasizes a useful pattern of miR-122 and -155 as ancillary markers to discriminate AR predominant cases from RHC in HCV positive patients after LT.

The severity of acute cellular rejection defined by Banff classification is associated with kidney allograft outcomes.

It is unclear if the severity or the timing of acute cellular rejection (ACR) defined by Banff classification 2009 is associated with graft survival. Borderline changes, TCMR I (interstitial rejection), and TCMR II/III (vascular rejection) were defined as low, moderate, and high ACR severity, respectively. Approximately 270 patients who had at least one episode of ACR were enrolled, 270 biopsies were chosen which showed the highest ACR severity of each patient and were negative for donor-specific antibodies (DSA), C4d, and microcirculation changes (MC). Six months were used as the cutoff to define early and late ACR; 370 patients without biopsy posttransplantation were recruited in the control group. Up to 8-year posttransplantation, death-censored graft survival (DCGS) rates of control, borderline, TCMR I, and TCMR II/III groups were 97.6%, 93.3%, 79.6%, and 73.6% (log rank test, P<0.001); the control group had significantly higher DCGS rate than the three ACR groups (each pairwise comparison yields P<0.05). The DCGS rate of late ACR was significantly lower compared with early ACR (63.6% vs. 87.4%, P<0.001). Intimal arteritis (Banff v-lesion) was an independent histologic risk factor correlated with long-term graft loss regardless of the timing of ACR. The v-lesions with minimal or high-grade tubulitis displayed similar graft survival (72.7% vs. 72.9%, P=0.96). All types of ACR affect long-term graft survival. Vascular or late ACR predict poorer graft survival; the extent of tubulointerstitial inflammation (TI) is of no prognostic significance for vascular rejection.