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After the occurrence of acute rejection following solid organ transplantation, high-dose glucocorticoid (steroid) pulse therapy is commonly used. However, high-dose steroid pulse therapy is ineffective for some patients, leading to steroid resistant acute rejection, which may easily result in graft loss and severely affect patient prognosis. It is currently believed that both cell-mediated rejection and antibody-mediated rejection are involved in the occurrence and development of steroid resistant acute rejection. The diagnosis and treatment of steroid resistant acute rejection after kidney transplantation have become relatively mature, while the focus on steroid resistant acute rejection after liver transplantation has been relatively low in the past in China, and a unified standardized treatment plan has not yet been formed. Therefore, this article reviews the pathogenesis, diagnosis, and treatment of steroid resistant acute rejection after liver transplantation, in order to provide a reference for the diagnosis and treatment of steroid resistant acute rejection after liver transplantation. [ABSTRACT FROM AUTHOR]

Rejection in kidney transplantation are significant barriers affecting the survival of recipients and transplant kidneys. To further standardize the clinical diagnosis and treatment of rejection in kidney transplant recipients in China, the Branch of Organ Transplantation of Chinese Medical Association and Branch of Organ Transplantation Physician of Chinese Medical Doctor Association organized kidney transplant experts, transplant immunologists and other experts. Based on the " Technical specification for clinical diagnosis and treatment of renal transplant rejection (2019 edition)" issued by Branch of Organ Transplantation of Chinese Medical Association, and referring to recent domestic and international research findings, expert consensus, guidelines, and mature clinical experience, combined with the current clinical situation of rejection diagnosis and treatment in kidney transplant recipients in China, the "Guidelines for clinical diagnosis and treatment of rejection in kidney transplant recipients in China" have been formulated. The content covers the clinical standard diagnosis and treatment of kidney transplant hyperacute rejection, acute rejection (acute T cell-mediated rejection, acute antibody-mediated rejection), and chronic rejection (chronic active T cell-mediated rejection, chronic active antibody-mediated rejection), aiming to provide theoretical and clinical practice references for the clinical diagnosis and treatment of rejection in Chinese kidney transplant recipients, with the goal of improving and promoting the quality of kidney transplantation. [ABSTRACT FROM AUTHOR]

All chronic and treatment-resistant acute rejections are "difficult-to-treat" and lead to progressive loss of graft function in kidney transplant recipients (KTR), as no effective treatment exists for such rejections to date. We review our experience with a novel strategy to treat such rejections by adding everolimus as a "rescue" to conventional triple maintenance therapy with prednisolone, mycophenolate mofetil and calcineurin inhibitor. We retrospectively analysed data in 28 KTR who received everolimus-based quadruple therapy at our institution for biopsy-proven chronic active T cell-mediated or antibody-mediated rejection (n = 19) or treatment-resistant acute rejections (n = 9) between 2011–2017. The primary outcome was 5-year death-censored graft survival. Main secondary outcomes were response to treatment defined by stable or improved graft function, 5-year patient survival and discontinuation rate of treatment. The Kaplan–Meier estimate for 5-year death-censored graft survival was 79% in all patients, 90% for patients with chronic active T cell-mediated rejections, 78% for chronic active antibody-mediated rejection and 67% for acute rejections. Response to treatment was achieved in 43% and 5-year patient survival was 94%. Treatment was stopped in 12 (43%) patients due to adverse events. Everolimus-based maintenance quadruple therapy, despite high rate of everolimus discontinuation due to adverse events, may be a valid approach in a subset of kidney transplant recipients with such difficult-to-treat rejections, which otherwise would lead to a high rate of graft loss. [ABSTRACT FROM AUTHOR]

Despite the growing interest in the role of regulatory B cells (Bregs) in autoimmunity, their distinct role and function in kidney transplant outcomes remain elusive. Here, we retrospectively analyzed the proportion of Bregs, transitional Bregs (tBregs) and memory Bregs (mBregs) and their capacity to produce IL-10 in non-rejected (NR) versus rejected (RJ) kidney transplant recipients. In the NR group, we observed a significant increase in the proportion of mBregs (CD19+CD24hiCD27+) but no difference in tBregs (CD19+CD24hiCD38+), as compared to the RJ group. We also observed a significant increase in IL-10-producing mBregs (CD19+CD24hiCD27+IL-10+) in the NR group. As our group and others have previously reported a potential role of the human leukocyte antigen G (HLA-G) in human renal allograft survival, notably through IL-10, we then investigated possible crosstalk between HLA-G and IL-10+ mBregs. Our ex vivo data suggest a role of HLA-G in enhancing IL-10+ mBreg expansion upon stimulation, which further decreased CD3+ T cell proliferation capability. Using RNA-sequencing (RNA-seq), we identified potential key signaling pathways involved in HLA-G-driven IL-10+ mBreg expansion, such as the MAPK, TNF and chemokine signaling pathways. Together, our study highlights a novel HLA-G-mediated IL-10-producing mBreg pathway that may serve as a therapeutic target to improve kidney allograft survival. [ABSTRACT FROM AUTHOR]

Early diagnosis of acute rejection is of significance for the protection of renal allograft function. Pathological puncture biopsy is the gold standard for the diagnosis of acute rejection of renal allografts. Nevertheless, it may provoke multiple complications, such as bleeding, infection and renal parenchymal injury, which limit its widespread application. In recent years, the sensitivity of contrast-enhanced ultrasound in the diagnosis of acute rejection has been constantly improved. Ultrasound-targeted microbubble technique has further enhanced the diagnostic specificity of contrast-enhanced ultrasound, making it possible to replace pathological puncture biopsy. Besides, in the field of acute rejection treatment, microbubble ultrasonic cavitation may promote local delivery of immunosuppressants by inducing sonoporation and exhibit anti-rejection effect. In this article, the application of contrast-enhanced ultrasound in the diagnosis and treatment of acute rejection after kidney transplantation was reviewed, aiming to provide reference for widespread application of contrast-enhanced ultrasound in kidney transplantation. [ABSTRACT FROM AUTHOR]

Outcomes after liver transplantation have continuously improved over the past decades, but long-term survival rates are still lower than in the general population. The liver has distinct immunological functions linked to its unique anatomical configuration and to its harbouring of a large number of cells with fundamental immunological roles. The transplanted liver can modulate the immunological system of the recipient to promote tolerance, thus offering the potential for less aggressive immunosuppression. The selection and adjustment of immunosuppressive drugs should be individualised to optimally control alloreactivity while mitigating toxicities. Routine laboratory tests are not accurate enough to make a confident diagnosis of allograft rejection. Although several promising biomarkers are being investigated, none of them is sufficiently validated for routine use; hence, liver biopsy remains necessary to guide clinical decisions. Recently, there has been an exponential increase in the use of immune checkpoint inhibitors due to the unquestionable oncological benefits they provide for many patients with advanced-stage tumours. It is expected that their use will also increase in liver transplant recipients and that this might affect the incidence of allograft rejection. Currently, the evidence regarding the efficacy and safety of immune checkpoint inhibitors in liver transplant recipients is limited and cases of severe allograft rejection have been reported. In this review, we discuss the clinical relevance of alloimmune disease, the role of minimisation/withdrawal of immunosuppression, and provide practical guidance for using checkpoint inhibitors in liver transplant recipients. [ABSTRACT FROM AUTHOR]

The impact of T cell-mediated rejection (TCMR) after liver transplantation (LT) on the alterations in the gut microbiota (GM) and associated intestinal environment represented by fecal organic acids (OAs) require further elucidation. A rat allogeneic LT model was prepared without immunosuppressants or antibiotics, and a syngeneic model was used as a control. Qualitative and quantitative analyses of fecal samples at fixed time points were performed. Correlation analyses were also performed between liver function and GMs and OA levels. In the allogeneic TCMR group, the number of predominant obligate anaerobes decreased as liver function declined. Clostridioides difficile, Enterobacteriaceae, Enterococcus, Streptococcus, and Staphylococcus were significantly increased. Regarding fecal OA concentration, short-chain fatty acid (SCFA) concentrations were depleted as liver function declined. In contrast, in the syngeneic group, GM and OAs exhibited only slight, transient, and reversible disturbances. In addition, alanine aminotransferase and total bilirubin were positively correlated with the number of Enterobacteriaceae and Enterococcus, and negatively correlated with the fecal concentration of SCFAs. The allogeneic TCMR model demonstrated distinct dysbiosis and depletion of fecal OAs as TCMR progressed after LT. The degree of graft injury was closely related to the number of specific bacterial strains and the concentrations of fecal SCFAs. [ABSTRACT FROM AUTHOR]

The continuous evolution of metabolomics over the past two decades has stimulated the search for metabolic biomarkers of many diseases. Metabolomic data measured from urinary samples can provide rich information of the biological events triggered by organ rejection in pediatric kidney transplant recipients. With additional validation, metabolic markers can be used to build clinically useful diagnostic tools. However, there are many methodological steps ranging from data processing to modeling that can influence the performance of the resulting metabolomic classifiers. In this study we focus on the comparison of various classification methods that can handle the complex structure of metabolomic data, including regularized classifiers, partial least squares discriminant analysis, and nonlinear classification models. We also examine the effectiveness of a physiological normalization technique widely used in the clinical and biochemical literature but not extensively analyzed and compared in urine metabolomic studies. While the main objective of this work is to interrogate metabolomic data of pediatric kidney transplant recipients to improve the diagnosis of T cell‐mediated rejection (TCMR), we also analyze three independent datasets from other disease conditions to investigate the generalizability of our findings. [ABSTRACT FROM AUTHOR]

Over the past 70 years, kidney transplantation has become not only the most mature but also the highest-success-rate surgery among all organ transplantation surgeries. However, the long-term survival of kidney transplant recipients is still challenged by such key factors as ischemia-reperfusion injury related to kidney transplantation, rejection, chronic renal allograft dysfunction, renal allograft fibrosis, immunosuppressive therapy, infections and others. Relevant fundamental and clinical studies have emerged endlessly. At the same time, the research related to kidney transplantation also becomes a new hot spot accordingly in the context of the normalization of novel coronavirus pneumonia. This article reviewed the cutting-edge hot spots in relation to the fundamental and clinical aspects of kidney transplantation together with relevant new techniques and new visions. The studies included in this article focused on the reports published by Chinese teams that are more applicable to the current situation of kidney transplantation in China, for the purpose of providing new thoughts and strategies for the diagnosis and treatment of kidney transplantation related issues in China. [ABSTRACT FROM AUTHOR]

Management of long-term immunosuppression following liver transplantation (LT) remains empirical. Surveillance liver biopsies in combination with transcriptional profiling could overcome this challenge by identifying recipients with active alloimmune-mediated liver damage despite normal liver tests, but this approach lacks applicability. Our aim was to investigate the utility of non-invasive tools for the stratification of stable long-term survivors of LT, according to their immunological risk and need for immunosuppression. We conducted a cross-sectional multicentre study of 190 adult LT recipients assessed to determine their eligibility to participate in an immunosuppression withdrawal trial. Patients had stable liver allograft function and had been transplanted for non-autoimmune non-replicative viral liver disease >3 years before inclusion. We performed histological, immunogenetic and serological studies and measured the intrahepatic transcript levels of an 11-gene classifier highly specific for T cell-mediated rejection (TCMR). In this cohort, 35.8% of patients harboured clinically silent fibro-inflammatory liver lesions (13.7% had mild damage and 22.1% had moderate-to-severe damage). The severity of liver allograft damage was positively associated with TCMR-related transcripts, class II donor-specific antibodies (DSAs), ALT, AST, and liver stiffness measurement (LSM), and negatively correlated with serum creatinine and tacrolimus trough levels. Liver biopsies were stratified according to their TCMR transcript levels using a cut-off derived from biopsies with clinically significant TCMR. Two multivariable prediction models, integrating ALT+LSM or ALT+class II DSAs, had a high discriminative capacity for classifying patients with or without alloimmune damage. The latter model performed well in an independent cohort of 156 liver biopsies obtained from paediatric liver recipients with similar inclusion/exclusion criteria. ALT, class II DSAs and LSM are valuable tools to non-invasively identify stable LT recipients without significant underlying alloimmunity who could benefit from minimisation of immunosuppression. A large proportion of liver transplant patients with normal liver tests have inflammatory liver lesions, which in 17% of cases are molecularly indistinguishable from those seen at the time of rejection. ALT, class II donor-specific antibodies and liver stiffness are useful in identifying patients with this form of subclinical rejection. We propose these markers as a useful tool to help clinicians determine if the immunosuppression administered is adequate. [Display omitted] • 22% of stable liver recipients harbour moderate-to-severe subclinical immune allograft damage. • Subclinical damage is linked to allograft immunogenicity and degree of immunosuppression. • Recipients with active underlying alloimmunity can be identified using non-invasive markers. [ABSTRACT FROM AUTHOR]

Background This study aims to examine the association of LIM zinc finger domain containing 1 (LIMS1) genotype with allograft rejection in an independent kidney transplant cohort. Methods We genotyped 841 kidney transplant recipients for the LIMS1 rs893403 variant by Sanger sequencing followed by polymerase chain reaction confirmation of the deletion. Recipients who were homozygous for the LIMS1 rs893403 genotype GG were compared with the AA/AG genotypes. The primary outcome was T cell–mediated or antibody-mediated rejection (TCMR or ABMR, respectively) and secondary outcome was allograft loss. Results After a median follow-up of 11.4 years, the rate of TCMR was higher in recipients with the GG genotype (n  = 200) compared with the AA/AG genotypes (n  = 641) [25 (12.5%) versus 35 (5.5%); P = 0.001] while ABMR did not differ by genotype [18 (9.0%) versus 62 (9.7%)]. Recipients with the GG genotype had 2.4 times higher risk of TCMR than those who did not have this genotype [adjusted hazard ratio2.43 (95% confidence interval 1.44–4.12); P = 0.001]. A total of 189 (22.5%) recipients lost their allografts during follow-up. Kaplan–Meier estimates of 5-year (94.3% versus 94.4%; P = 0.99) and 10-year graft survival rates (86.9% versus 83.4%; P = 0.31) did not differ significantly in the GG versus AA/AG groups. Conclusions Our study demonstrates that recipient LIMS1 risk genotype is associated with an increased risk of TCMR after kidney transplantation, confirming the role of the LIMS1 locus in allograft rejection. These findings may have clinical implications for the prediction and clinical management of kidney transplant rejection by pretransplant genetic testing of recipients and donors for LIMS1 risk genotype. [ABSTRACT FROM AUTHOR]

The Banff conference on allograft pathology (Banff conference) and the establishment of Banff classification on allograft pathology (Banff classification) are milestones in the development of international allograft pathology. At present, all organ transplantation centers around the world routinely perform pathological diagnosis by biopsy of the transplant kidney according to Banff classification. Subsequently, the consensus process and update mode of Banff classification for transplant kidney was quickly extended to transplant heart, lung, liver, pancreas, and small intestine, etc. The Banff conference has not only become a thematic meeting that includes the pathology study and discussion of various transplant organs, but also gradually developed unified diagnostic standard for the biopsy of each transplant organ, which better promoted the accurate diagnosis and treatment of complications after organ transplantation. This article summarized the history of international allograft pathology research, the Banff conference and Banff classification in promoting organ transplantation, which aimed to provide a reference for the smooth development of clinical organ transplantation. [ABSTRACT FROM AUTHOR]

Summary: Preformed donor‐reactive T cells are relatively resistant to standard immunosuppression and account for an increased incidence of T cell‐mediated rejection (TCMR) and inferior kidney allograft outcomes. We analyzed 150 living donor kidney transplant recipients (KTRs) of a first kidney allograft. Ninety‐eight ABO‐compatible (ABOc) and 52 ABO‐incompatible (ABOi) KTRs were included. Samples were collected at 6 time points, before rituximab, before immunoadsorption and pretransplantation, at +1, +2, and +3 months posttransplantation, and donor‐reactive T cells were measured by interferon‐γ ELISPOT assay. Twenty of 98 ABOc (20%) and 12 of 52 ABOi KTRs (23%) showed positive pretransplant ELISPOT. Eight of 20 ABOc‐KTRs (40%) with positive pretransplant ELISPOT showed TCMR, whereas 17 of 78 ABOc‐KTRs (22%) with negative pretransplant ELISPOT did (P = 0.148). Seven of 12 ABOi KTRs (57%) with positive pretransplant ELISPOT showed TCMR, whereas only 3 of 40 ABOi KTRs (8%) with negative pretransplant ELISPOT did (P < 0.001). Interestingly, 6 of 7 ABOi KTRs with positive pretransplant ELISPOT that persists after ABO desensitization developed TCMR. Among 118 KTRs with negative pretransplant ELISPOT, 10 of 72 ABOc‐KTRs (14%), but 0 of 46 ABOi KTRs, developed positive posttransplant ELISPOT (P = 0.006). Preformed donor‐reactive T cells that persist despite ABO desensitization identify KTRs at highest risk of TCMR. Less de‐novo donor‐reactive T cells after ABO desensitization may account for less TCMR. Both, the use of rituximab and early initiation of calcineurin inhibitor‐based maintenance immunosuppression may contribute to these findings. [ABSTRACT FROM AUTHOR]

Background The emergence of molecular systems offers opportunities for improving the assessment of rejection in heart transplant biopsy specimens. The present study developed a microarray-based system for assessing heart transplant endomyocardial biopsy (EMB) specimens. Methods We analyzed 331 protocol or for-cause EMB specimens from 221 subjects in 3 centers (Edmonton, Bologna, and Paris). Unsupervised principal component analysis (PCA) and archetype analysis used rejection-associated transcripts (RATs) shown in kidney transplants to be associated with antibody-mediated rejection (ABMR) or T cell–mediated rejection (TCMR), or both. To compare EMB specimens to kidney biopsy specimens, rejection status in both was simplified to TCMR, ABMR, or no rejection. Results The pattern of RAT expression was similar in EMB and kidney specimens, permitting use of RATs to assign scores and group (“cluster”) membership to each EMB, independent of histology. Three clusters emerged in EMB specimens, similar to kidney specimens: TCMR, ABMR, and no rejection. This permitted each EMB specimen to be given 3 scores and assigned to 1 cluster by its highest score. There was significant agreement between molecular phenotype—archetype scores or clusters—and both histologic diagnoses and donor-specific antibody. Area under curve estimates for predicting histologic TCMR, ABMR, and no rejection by molecular assessment were lower in EMB specimens than in kidney specimens, reflecting more uncertainty in EMB specimens, particularly in histologic diagnosis of TCMR. Conclusions Rejection-associated transcripts can be used to estimate the probability of TCMR and ABMR in heart transplant specimens, providing a new dimension to improve the accuracy of diagnoses and an independent system for recalibrating the histology guidelines. [ABSTRACT FROM AUTHOR]

Ushigome H, Okamoto M, Koshino K, Nobori S, Okajima H, Masuzawa N, Urasaki K, Yoshimura N. Findings of graft biopsy specimens within 90 days after ABO blood group incompatible living donor kidney transplantation compared with ABO-identical and non-identical transplantation. Clin Transplant 2010: 24 (Suppl. 22): 16–21. © 2010 John Wiley & Sons A/S. As immunosuppressive therapy has advanced, we have markedly improved the outcome of ABO blood group incompatible living donor kidney transplantation. Consequently, graft survival at early phase after ABO-incompatible transplantation has been favorable than ABO-compatible transplantation in Japan. But in these days, it has been assumed that transplant glomerulopathy within one yr after ABO-incompatible kidney transplantation might be significantly precipitated. That may be because of chronic, active antibody-mediated rejection (AMR). We performed kidney graft biopsies at the early phase within 90 d after living donor kidney transplantation that involved the episode and protocol biopsies and studied findings of graft biopsy specimens when compared with ABO incompatible and compatible involving non-identical and identical transplantations. In ABO-incompatible transplant cases, the ratio occurring glomerulitis, especially severe injury of g 2–3, was significantly higher than that of identical and non-identical transplant cases (p < 0.01). There was no significant difference in t score, i score, ptc score and v score between three transplant groups. The cases occurring AMR were concordant with the cases recognized with severe glomerulitis. AMR was difficult to be diagnosed by C4d analysis in ABO-incompatible transplant cases. Glomerular injury score, g score, may be considered as more significant and the injury should be cured thoroughly. [ABSTRACT FROM AUTHOR]

In this clinical validation study, we developed and validated a urinary Q-Score generated from the quantitative test QSant, formerly known as QiSant, for the detection of biopsy-confirmed acute rejection in kidney transplants. Using a cohort of 223 distinct urine samples collected from three independent sites and from both adult and pediatric renal transplant patients, we examined the diagnostic utility of the urinary Q-Score for detection of acute rejection in renal allografts. Statistical models based upon the measurements of the six QSant biomarkers (cell-free DNA, methylated-cell-free DNA, clusterin, CXCL10, creatinine, and total protein) generated a renal transplant Q-Score that reliably differentiated stable allografts from acute rejections in both adult and pediatric renal transplant patients. The composite Q-Score was able to detect both T cell-mediated rejection and antibody-mediated rejection patients and differentiate them from stable non-rejecting patients with a receiver–operator characteristic curve area under the curve of 99.8% and an accuracy of 98.2%. Q-Scores < 32 indicated the absence of active rejection and Q-Scores ≥ 32 indicated an increased risk of active rejection. At the Q-Score cutoff of 32, the overall sensitivity was 95.8% and specificity was 99.3%. At a prevalence of 25%, positive and negative predictive values for active rejection were 98.0% and 98.6%, respectively. The Q-Score also detected subclinical rejection in patients without an elevated serum creatinine level but identified by a protocol biopsy. This study confirms that QSant is an accurate and quantitative measurement suitable for routine monitoring of renal allograft status. [ABSTRACT FROM AUTHOR]

Suppressor of cytokine signaling (SOCS) proteins have acknowledged roles in regulation of immune responses. Moreover, their role in the evolution of allograft rejection is being elucidated. In the current investigation, we measured transcript levels of SOCS1-4 in the peripheral blood of a group of renal transplant recipients including both rejected and non-rejected allografts. Expression analyses showed that relative expression of SOCS2 was significantly higher in transplant-rejected male patients compared to non-rejected group. However, such significant difference was not detected between female subjects. Expression of SOCS2 was significantly higher in T-cell-mediated rejection group compared with non-rejected individuals with creatinine rise (Relative expression difference [95% CrI] =6.74 [0.94, 12.65], P = 0.043). Conversely, SOCS4 expression was significantly lower in T-cell-mediated rejection group compared with non-rejected individuals with creatinine rise (Relative expression difference [95% CrI] = −0.35 [−0.63, −0.1], P = 0.008). Patterns of correlations between expression levels of SOCS genes were different in non-rejected group. The obtained results indicate the role SOCS genes in development of allograft rejection. • Expression analyses showed that relative expression of SOCS2 was significantly higher in transplant-rejected male patients. • Such significant difference was not detected between female subjects. • Expression of SOCS2 was significantly higher in T-cell-mediated rejection group compared with non-rejected individuals. • SOCS4 expression was significantly lower in T-cell-mediated rejection group compared with non-rejected individuals with creatinine rise. • Patterns of correlations between expression levels of SOCS genes were different in non-rejected group. [ABSTRACT FROM AUTHOR]

The presence of B-cell clusters in allogenic T cell-mediated rejection (TCMR) of kidney allografts is linked to more severe disease entities. In this study we characterized B-cell infiltrates in patients with TCMR and examined the role of serum CXCL-13 in these patients and experimentally. CXCL-13 serum levels were analyzed in 73 kidney allograft recipients at the time of allograft biopsy. In addition, four patients were evaluated for CXCL13 levels during the first week after transplantation. ELISA was done to measure CXCL-13 serum levels. For further mechanistic understanding, a translational allogenic kidney transplant (ktx) mouse model for TCMR was studied in BalbC recipients of fully mismatched transplants with C57BL/6 donor kidneys. CXCL-13 serum levels were measured longitudinally, CD20 and CD3 composition and CXCL13 mRNA in tissue were examined by flow cytometry and kidneys were examined by histology and immunohistochemistry. We found significantly higher serum levels of the B-cell chemoattractant CXCL13 in patients with TCMR compared to controls and patients with borderline TCMR. Moreover, in patients with acute rejection within the first week after ktx, a >5-fold CXCL13 increase was measured and correlated with B-cell infiltrates in the biopsies. In line with the clinical findings, TCMR in mice correlated with increased systemic serum-CXCL13 levels. Moreover, renal allografts had significantly higher CXCL13 mRNA expression than isogenic controls and showed interstitial CD20+ B-cell clusters and CD3+ cell infiltrates accumulating in the vicinity of renal vessels. CXCL13 blood levels correlate with B-cell involvement in TCMR and might help to identify patients at risk of a more severe clinical course of rejection. [ABSTRACT FROM AUTHOR]