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BACKGROUND: Acute lung allograft dysfunction (ALAD) is an imprecise syndrome denoting concern for the onset of chronic lung allograft dysfunction (CLAD). Mechanistic biomarkers are needed that stratify risk of ALAD progression to CLAD. We hypothesized that single cell investigation of bronchoalveolar lavage (BAL) cells at the time of ALAD would identify immune cells linked to progressive graft dysfunction. METHODS: We prospectively collected BAL from consenting lung transplant recipients for single cell RNA sequencing. ALAD was defined by a ≥10% decrease in FEV1 not caused by infection or acute rejection and samples were matched to BAL from recipients with stable lung function. We examined cell compositional and transcriptional differences across control, ALAD with decline, and ALAD with recovery groups. We also assessed cell-cell communication. RESULTS: BAL was assessed for 17 ALAD cases with subsequent decline (ALAD declined), 13 ALAD cases that resolved (ALAD recovered), and 15 cases with stable lung function. We observed broad differences in frequencies of the 26 unique cell populations across groups (p = 0.02). A CD8 T cell (p = 0.04) and a macrophage cluster (p = 0.01) best identified ALAD declined from the ALAD recovered and stable groups. This macrophage cluster was distinguished by an anti-inflammatory signature and the CD8 T cell cluster resembled a Tissue Resident Memory subset. Anti-inflammatory macrophages signaled to activated CD8 T cells via class I HLA, fibronectin, and galectin pathways (p

Cardiac allograft vasculopathy (CAV) causes late graft failure and mortality after heart transplantation. Donor-specific antibodies (DSAs) lead to chronic endothelial cell injury, inflammation, and arterial intimal thickening. In this study, GeoMx digital spatial profiling was used to analyze arterial areas of interest (AOIs) from CAV+DSA+ rejected cardiac allografts (N = 3; 22 AOIs total). AOIs were categorized based on CAV neointimal thickening and underwent whole transcriptome and protein profiling. By comparing our transcriptomic data with that of healthy control vessels of rapid autopsy myocardial tissue, we pinpointed specific pathways and transcripts indicative of heightened inflammatory profiles in CAV lesions. Moreover, we identified protein and transcriptomic signatures distinguishing CAV lesions exhibiting low and high neointimal lesions. AOIs with low neointima showed increased markers for activated inflammatory infiltrates, endothelial cell activation transcripts, and gene modules involved in metalloproteinase activation and TP53 regulation of caspases. Inflammatory and apoptotic proteins correlated with inflammatory modules in low neointima AOIs. High neointima AOIs exhibited elevated TGFβ-regulated transcripts and modules enriched for platelet activation/aggregation. Proteins associated with growth factors/survival correlated with modules enriched for proliferation/repair in high neointima AOIs. Our findings reveal novel insight into immunological mechanisms mediating CAV pathogenesis.

MRI plays an important role in the evaluation of kidney allografts for vascular complications as well as parenchymal insults. Transplant renal artery stenosis, the most common vascular complication of kidney transplant, can be evaluated by MRA using gadolinium and nongadolinium contrast agents as well as by unenhanced MRA techniques. Parenchymal injury occurs through a variety of pathways, including graft rejection, acute tubular injury, BK polyomavirus infection, drug-induced interstitial nephritis, and pyelonephritis. Investigational MRI techniques have sought to differentiate among these causes of dysfunction as well as to assess the degree of interstitial fibrosis or tubular atrophy (IFTA)-the common end pathway for all of these processes-which is currently evaluated by invasively obtained core biopsies. Some of these MRI sequences have shown promise in not only assessing the cause of parenchymal injury but also assessing IFTA noninvasively. This review describes current clinically used MRI techniques and previews promising investigational MRI techniques for assessing complications of kidney grafts.

There is a need to reconsider the acceptance of organs from donors considered suboptimal, in the absence of data. Toxoplasma antibody-positive donors (TPD) constitute one such group. The objective of our study was to compare graft survival in deceased donor renal transplant (Tx) recipients, stratified by Toxoplasma IgG status, using the Organ Procurement and Transplantation Network (OPTN) database. A log-linear event history regression model for graft failure categorized by Toxoplasma IgG status, adjusting for confounders was applied to first kidney-only Tx recipients from 2018 to 2022. Of the 51,422 Tx, 4,317 (8.4%) were from TPD. Acute rejection and graft failure (5% each) were similar between groups. Crude graft failure was 7.3 failures per 100 person-years for TPD recipients compared to 6.5 failures per 100 person-years for the Toxoplasma-negative group (p 0.008). The crude failure rate ratio was 1.14 with an adjusted hazard rate ratio of 1.04 (95% CI: 0.94, 1.15, p 0.39). In renal Tx recipients, TPD graft recipients have comparable survival to Tx from Toxoplasma-negative recipients. While caution and close monitoring of recipients post-Tx for surveillance of disseminated toxoplasmosis are still warranted, our study suggests that patients can be successfully managed using TPD organs.

BackgroundRemote ischemic conditioning (RIC) has the potential to benefit graft function following kidney transplantation by reducing ischemia-reperfusion injury; however, the current clinical evidence is inconclusive. This meta-analysis with trial sequential analysis (TSA) aimed to determine whether RIC improves graft function after kidney transplantation.MethodsA comprehensive search was conducted on PubMed, Cochrane Library, and EMBASE databases until June 20, 2023, to identify all randomized controlled trials that examined the impact of RIC on graft function after kidney transplantation. The primary outcome was the incidence of delayed graft function (DGF) post-kidney transplantation. The secondary outcomes included the incidence of acute rejection, graft loss, 3- and 12-month estimated glomerular filtration rates (eGFR), and the length of hospital stay. Subgroup analyses were conducted based on RIC procedures (preconditioning, perconditioning, or postconditioning), implementation sites (upper or lower extremity), and graft source (living or deceased donor).ResultsOur meta-analysis included eight trials involving 1038 patients. Compared with the control, RIC did not significantly reduce the incidence of DGF (8.8% vs. 15.3%; risk ratio = 0.76, 95% confidence interval [CI], 0.48-1.21, P = 0.25, I2 = 16%), and TSA results showed that the required information size was not reached. However, the RIC group had a significantly increased eGFR at 3 months after transplantation (mean difference = 2.74 ml/min/1.73 m2, 95% CI: 1.44-4.05 ml/min/1.73 m2, P

Background: Tacrolimus is a potent calcineurin inhibitor (CNI) that is principally used as a first-line immunosuppressant for the prophylaxis of allograft rejection in liver transplantation (LT) patients. In clinical practice, prescribing the optimal tacrolimus dosage is complicated by its narrow therapeutic index and high pharmacokinetic variability. Thus, performing therapeutic drug monitoring (TDM) of only tacrolimus may not provide optimal drug levels. However, other influential clinical factors affecting tacrolimus levels, such as hemoglobin (Hb), hematocrit, and total bilirubin (TBIL), should be considered while adjusting tacrolimus levels. This case report aims to introduce clinicians and their teams to taking the pharmacokinetic prediction equation into consideration for a better understanding of tacrolimus dosage adjustment during the early postoperative LT. Case presentation: In this case report, an 18-year-old male patient of Thai ethnicity was admitted for orthotropic liver transplantation, and tacrolimus was prescribed as a cornerstone immunosuppressive agent. In the immediate postoperative period, which is the most challenging period in liver transplantation, the population pharmacokinetics predictive equation was clinically used to assist in dosage adjustment of tacrolimus by considering the significant clinical factors in this case. Hemoglobin and total bilirubin levels were deemed significant clinical factors affecting the oral clearance (CL/F) of tacrolimus. First, a decrease in the Hb concentration increases the free drug concentration and therefore increases the CL/F of tacrolimus. Second, an elevated TBIL decreases the biliary excretion of tacrolimus, resulting in a decrease in the CL/F of tacrolimus. Thus, dose optimization of tacrolimus would be accurate when taking the pharmacokinetic prediction equation into consideration. Moreover, the results may contribute to a better understanding of tacrolimus pharmacokinetic variability in each transplant patient during the immediate postoperative course. Conclusions: Hemoglobin and total bilirubin were significant clinical factors influencing the oral clearance of tacrolimus early after liver transplantation. A decrease in the hemoglobin concentration would increase the free drug concentration and therefore increase the oral clearance of tacrolimus. An elevated total bilirubin decreases the biliary excretion of tacrolimus, resulting in a decrease in the oral clearance of tacrolimus. [ABSTRACT FROM AUTHOR]

AbstractGraft rejection and Graft-versus-host disease (GVHD) are some of the significant factors resulting in morbidity and mortality following allogeneic hematopoietic cell transplantation. Prophylaxis for GVHD using T-cell depleting agents is helpful in reducing the transplant-related mortality and graft rejection. Both tATG and fATG exhibit varied amounts of antibody specificities and perform distinct immunomodulatory effects, regardless of their capacity to deplete T-lymphocytes. We conducted this single-center, retrospective study at our center to compare both formulations. Twenty-six patients were included in the study, 13 in each cohort. The median age at diagnosis of β-thalassemia was 5 months (range, 3–12 months) in the tATG group and 6 months (range, 3–9 months) in the f-ATG group, respectively. Acute GVHD was observed in 1 (7.7) and 2(15.4) in the tATG and fATG group, respectively. No cases of chronic GVHD were observed in either group. There was no difference in the mixed chimerism observed at 6 months in both groups, tATG (n = 5, 38.5%) and fATG (n = 6, 46.15). There was 1 (7.6) rejection at day +72 observed in the tATG group, whereas no rejection was observed in the fATG group. At a mean follow-up duration of 288 days since transplant, there were no deaths in either of the groups. In conclusion, both ATG preparations showed equivalent effectiveness in preventing rejections and GVHD. However, further larger studies are required to establish the long-term efficacy and safety of both formulations in ASCT. [ABSTRACT FROM AUTHOR]

Current monitoring after heart transplantation (HT) employs repeated invasive endomyocardial biopsies (EMB). Although positive EMB confirms rejection, EMB fails to predict impending, subclinical, or EMB-negative rejection events. While non-human leukocyte antigen (non-HLA) antibodies have emerged as important risk factors for antibody-mediated rejection after HT, their use in clinical risk stratification has been limited. A systematic review of the role of non-HLA antibodies in rejection pathologies has the potential to guide efforts to overcome deficiencies of EMB in rejection monitoring. Databases were searched to include studies on non-HLA antibodies in HT recipients. Data collected included the number of patients, type of rejection, non-HLA antigen studied, association of non-HLA antibodies with rejection, and evidence for synergistic interaction between non-HLA antibodies and donor-specific anti-human leukocyte antigen antibody (HLA-DSA) responses. A total of 56 studies met the inclusion criteria. Strength of evidence for each non-HLA antibody was evaluated based on the number of articles and patients in support versus against their role in mediating rejection. Importantly, despite previous intense focus on the role of anti-major histocompatibility complex class I chain-related gene A (MICA) and anti-angiotensin II type I receptor antibodies (AT1R) in HT rejection, evidence for their involvement was equivocal. Conversely, the strength of evidence for other non-HLA antibodies supports that differing rejection pathologies are driven by differing non-HLA antibodies. This systematic review underscores the importance of identifying peri-HT non-HLA antibodies. Current evidence supports the role of non-HLA antibodies in all forms of HT rejection. Further investigations are required to define the mechanisms of action of non-HLA antibodies in HT rejection. [ABSTRACT FROM AUTHOR]

Molecular testing with gene-expression profiling (GEP) and donor-derived cell-free DNA (dd-cfDNA) is increasingly used in the surveillance for acute cellular rejection (ACR) after heart transplant. However, the performance of dual testing over each test individually has not been established. Further, the impact of dual noninvasive surveillance on clinical decision-making has not been widely investigated. We evaluated 2,077 subjects from the Surveillance HeartCare Outcomes Registry registry who were enrolled between 2018 and 2021 and had verified biopsy data and were categorized as dual negative, GEP positive/dd-cfDNA negative, GEP negative/dd-cfDNA positive, or dual positive. The incidence of ACR and follow-up testing rates for each group were evaluated. Positive likelihood ratios (LRs+) were calculated, and biopsy rates over time were analyzed. The incidence of ACR was 1.5% for dual negative, 1.9% for GEP positive/dd-cfDNA negative, 4.3% for GEP negative/dd-cfDNA positive, and 9.2% for dual-positive groups. Follow-up biopsies were performed after 8.8% for dual negative, 14.2% for GEP positive/dd-cfDNA negative, 22.8% for GEP negative/dd-cfDNA positive, and 35.4% for dual-positive results. The LR+ for ACR was 1.37, 2.91, and 3.90 for GEP positive, dd-cfDNA positive, and dual-positive testing, respectively. From 2018 to 2021, biopsies performed between 2 and 12-months post-transplant declined from 5.9 to 5.3 biopsies/patient, and second-year biopsy rates declined from 1.5 to 0.9 biopsies/patient. At 2 years, survival was 94.9%, and only 2.7% had graft dysfunction. Dual molecular testing demonstrated improved performance for ACR surveillance compared to single molecular testing. The use of dual noninvasive testing was associated with lower biopsy rates over time, excellent survival, and low incidence of graft dysfunction. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Haploidentical hematopoietic stem cell transplant (HSCT) is a curative treatment especially for countries where bone marrow registries are nonexistent. We present our experience with haploidentical HSCT in pediatric patients. Methods: Retrospective data collected and analyzed for patients ≤18 years, from January 2017 to December 2022. Results: The cohort consisted of 20 patients with median age at transplant of 61.5 (IQR: 124) months. Fourteen (70%) were malignant and 6 (30%) were benign diseases. Donors were father in majority (9/20; 45%). Stem cell source was peripheral blood 8, marrow 8, and combined 4. c‐specific antibodies were positive in 6 (30%). Median CD34 cell dose infused: 9.35 × 106/kg. Median engraftment time: 15 (IQR: 17) days. Acute and chronic graft‐versus‐host disease (GVHD) occurred in 12/20 (60%) and 5/20 (25%), respectively. Complications included infection/sepsis (14/20; 70%), cytomegalovirus reactivation (14/20; 70%), sinusoidal obstruction syndrome (1/20; 5%), primary graft failure (PGF) (6/20; 30%), and secondary graft failure (4/20; 20%). PGF was more common in benign conditions (p = 0.003) and less prevalent in cases with aGVHD (p = 0.007). aGVHD was more common in malignant conditions (p = 0.007). Overall survival (OS), relapse‐free survival (RFS), and treatment‐related mortality (TRM) were 40%, 50%, and 35%, respectively. Median time of survival and relapse were 8 (IQR: 15) and 9 (IQR: 13) months, respectively. Conclusion: OS was comparable to that of other low–middle‐income countries. GVHD was a major challenge, along with sepsis and CMV infection. Half of the leukemias relapsed. Graft failure was a major concern in nonmalignant diseases. [ABSTRACT FROM AUTHOR]

Background: Tocilizumab prevents the clinical worsening of chronic active antibody-mediated rejection (CAAMR) in kidney transplant recipients. Following a global shortage of the intravenous pharmaceutical form in 2022, patients were switched from monthly intravenous administration of 8 mg/kg to weekly subcutaneous injection of 162 mg, raising the question of bioequivalence between these schemes of administration. Aims: We aimed to compare the areas under the curve (AUC) of tocilizumab in virtual simulations of populations treated with the two administration schemes and to identify the covariates that could contribute to pharmacokinetic variability of tocilizumab in kidney transplant patients with CAAMR who received tocilizumab as salvage treatment. Methods: This retrospective monocentric study included 43 kidney transplant patients (202 tocilizumab concentrations) with CAAMR treated with intravenous or subcutaneous tocilizumab between December 2020 and January 2023. We developed a population pharmacokinetic model using nonlinear mixed effects modeling and identified the covariates that could contribute to tocilizumab AUC variability. Monte Carlo simulations were then performed to assess the subcutaneous and intravenous tocilizumab AUC for 0–28 days (M1), 56–84 days (M3), 140–168 days (M6), and 308–336 days (M12). Bioequivalence was defined by SC/IV AUC geometric mean ratios (GMRs) between 0.80 and 1.25. Results: A two-compartment model with parallel linear and nonlinear elimination best described the concentration–time data. Significant covariates for tocilizumab clearance were body weight, urinary albumin-to-creatinine ratio (ACR), and inflammation status [C-reactive protein (CRP) ≥ 5 mg/L]. The GMR values and their 90% confidence intervals at M3, M6, and M12 were within the 0.8–1.25 margin for equivalence. Conversely, the 90% prediction intervals of the GMR were much wider than the 90% confidence intervals and did not fall within 0.8 and 1.25. Conclusions: From month 3 of treatment, the subcutaneous and intravenous tocilizumab administration schemes provided average bioequivalent pharmacokinetic exposure at the population level but not at the individual level. Body weight, inflammation, ACR, and administration scheme should be considered to personalize the dose of tocilizumab for patients with CAAMR. Further studies are required to determine the target of tocilizumab exposure in kidney transplant patients with CAAMR. [ABSTRACT FROM AUTHOR]

In human leukocyte antigen (HLA)-mismatched allogeneic stem cell transplantation settings, donor-specific anti-HLA antibodies (DSAs) can independently lead to graft failure, including both primary graft rejection and primary poor graft function. Although several strategies, such as plasma exchange, intravenous immunoglobulin, rituximab, and bortezomib, have been used for DSA desensitization, the effectiveness of desensitization and transplantation outcomes in some patients remain unsatisfactory. In this review, we summarized recent research on the prevalence of anti-HLA antibodies and the underlying mechanism of DSAs in the pathogenesis of graft failure. We mainly focused on desensitization strategies for DSAs, especially novel methods that are being investigated in the preclinical stage and those with promising outcomes after preliminary clinical application. [ABSTRACT FROM AUTHOR]

Objective: To review the efficacy and safety of eculizumab for prevention and treatment of antibody-mediated rejection (AMR) in lung transplant recipients (LTRs). Data Sources: A literature search of PubMed and the Cochrane Controlled Trials Register (2007 to mid-October 2023) was performed using the following search terms: eculizumab, complement inhibitor, solid organ transplant, lung transplant, and AMR. Study Selection and Data Extraction: All relevant English-language studies were reviewed and considered. Data Synthesis: Eculizumab, a monoclonal antibody that binds complement protein C5 to inhibit its cleavage and subsequent generation of the membrane attack complex, is currently approved to treat paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, generalized myasthenia and neuromyelitis optica spectrum disorder. Given the role of antibodies directed against donor antigens that are produced by allospecific B-cells and plasma cells in AMR, eculizumab is being investigated for use within this indication. Three case reports have described the successful use of eculizumab for the prevention and treatment of AMR in LTRs. Given this lack of robust data, evidence for the use of eculizumab in other solid organ transplant recipients is of increased value. Early experiences from a single center's use of eculizumab in LTRs are also described. Relevance to Patient Care and Clinical Practice: Lung transplant is a recognized treatment for end-stage lung disease, though complications posttransplant can be associated with significant morbidity and mortality. While prevention and management of AMR remains a substantial challenge without comprehensive guidance from societal guidelines, recently published literature may be helpful to guide clinical practice using alternative treatment options. However, this remains an area of great clinical importance, given the impact of AMR on long-term allograft function. Conclusions: Optimizing use of current therapies, as well as identifying and advancing novel therapeutic modalities such as eculizumab, are vital for the improvement of AMR prevention and treatment in LTRs to extend long-term allograft function and survival. [ABSTRACT FROM AUTHOR]

Antibody-mediated rejection (AMR) is a major cause of graft failure limiting long-term graft survival after kidney transplantation. Current diagnostic strategy to detect AMR is suboptimal and requires further improvement. Previously suggested treatment regimens for AMR could not demonstrate efficacy, however novel therapeutic agents are currently under investigation. Donor-derived cell-free DNA (dd-cfDNA) is a novel noninvasive biomarker for allograft injury, that has been mainly studied in the context of rejection. Its short-half-life in circulation and injury-dependent release are its key advantages that contribute to its superior diagnostic accuracy, compared to traditional biomarkers. Moreover, previous studies showed that dd-cfDNA-release is well-linked to histological and molecular features of AMR, and thus able to reflect real-time injury. Further observations suggest that dd-cfDNA can be used as a suitable screening tool for early detection of AMR in patients with donor-specific-anti-HLA-antibodies (DSA), as well as for monitoring AMR activity after anti-rejection treatment. The weight of evidence suggests that the integration of dd-cfDNA in the graft surveillance of patients with AMR, or those suspicious of AMR (e.g., due to the presence of donor-specific anti-HLA-antibodies) has an added value and might have a positive impact on outcomes in this specific cohort. [ABSTRACT FROM AUTHOR]

Introduction: Despite significant advances in surgical techniques and patient outcomes, organ transplantation (OT) remains fraught with legal challenges and ethical dilemmas. This study aims to address the notable gap in literature on malpractice claims specifically related to OT, providing insights into litigation trends, outcomes, and implications for medical practice and patient care. Methods: We retrospectively queried the Verdictsearch database from 1988 to 2023, and captured malpractice claims involving several organs. Data on demographics, organ types, and litigation outcomes were collected to compare compensation across different categories of malpractice and patient outcomes. Results: Out of 292 malpractice cases identified, 62 met inclusion criteria, distributed across 19 states with kidney being the most implicated organ (46.8%). Defendants prevailed in 53.2% of cases, while settlements were reached in 29.0%, and plaintiffs won in 16.1% of cases. Surgical errors and complications were the most frequent allegations, followed by medication and treatment errors. The median compensation for deceased plaintiffs was significantly higher ($1,300,000) compared to living plaintiffs at litigation initiation ($128,000). Discussion: Our study sheds light on the challenges and trends in malpractice litigation within the field of OT. By identifying key areas of concern and the influence of patient outcomes on litigation resolution, this study offers valuable insights for healthcare providers, legal practitioners, and policymakers aimed at enhancing patient safety, reducing litigation risks, and fostering a deeper understanding of the ethical and legal complexities in OT. [ABSTRACT FROM AUTHOR]

Introduction: Understanding immune cell dynamics in kidney transplantation may provide insight into the mechanisms of rejection and improve patient management. B cells have gained interest with a special relevance of the "regulatory" subsets and their graft outcome prognostic value. In this study, we aimed to prove that the direct immunophenotyping and target gene expression analysis of kidney transplant patients' fresh whole blood will help to identify graft rejection risk and assist in the monitoring of kidney transplanted patients. Methods: We employed flow cytometry and qPCR techniques to characterize B and T cell subsets within fresh whole blood samples, with particular emphasis on transitional B cells (TrB) identified as CD19+CD24hiCD38hi. TrB are a relevant population in the context of kidney transplantation and are closely associated with regulatory B cells (Bregs) in humans. Patients were monitored, tracking pertinent clinical parameters and kidney-related events, including alterations in graft function and episodes of biopsy proven rejection. Results: Higher percentages of TrB cells at 3 months after transplantation were positively associated with better graft outcomes and lower biopsy-proven acute rejection risk. Furthermore, a novel panel of B cell regulatory associated genes was validated at 3 months post-transplantation by qPCR analysis of peripheral blood mononuclear cell (PBMC) mRNA, showing high predictive power of graft events and prognostic value. Discussion: These findings suggest that monitoring TrB may provide interesting patient management information, improve transplant outcomes, and allow for personalized drug regimens to minimize clinical complications. [ABSTRACT FROM AUTHOR]

Alloreactive memory T cells have been implicated as central drivers of transplant rejection. Perplexingly, innate cytokines, such as IL-6, IL-1ß, and IL-12, are also associated with rejection of organ transplants. However, the pathways of innate immune activation in allogeneic transplantation are unclear. While the role of microbial and cell death products has been previously described, we identified alloreactive memory CD4 T cells as the primary triggers of innate inflammation. Memory CD4 T cells engaged MHC II-mismatched dendritic cells (DCs), leading to the production of innate inflammatory cytokines. This innate inflammation was independent of several pattern recognition receptors and was primarily driven by TNF superfamily ligands expressed by alloreactive memory CD4 T cells. Blocking of CD40L and TNFa resulted in dampened inflammation, and mice genetically deficient in these molecules exhibited prolonged survival of cardiac allografts. Furthermore, myeloid cell and CD8 T cell infiltration into cardiac transplants was compromised in both CD40L-and TNFa-deficient recipients. Strikingly, we found that priming of naive alloreactive CD8 T cells was dependent on licensing of DCs by memory CD4 T cells. This study unravels the key mechanisms by which alloreactive memory CD4 T cells contribute to destructive pathology and transplant rejection. [ABSTRACT FROM AUTHOR]

Humoral immunity is a major waypoint towards chronic allograft dysfunction in lung transplantation (LT) recipients. Though allo-immunization and antibody-mediated rejection (AMR) are well-known entities, some diagnostic gaps need to be addressed. Morphological analysis could be enhanced by digital pathology and artificial intelligence-based companion tools. Graft transcriptomics can help to identify graft failure phenotypes or endotypes. Donorderived cell free DNA is being evaluated for graft-loss risk stratification and tailored surveillance. Preventative therapies should be tailored according to risk. The donor pool can be enlarged for candidates with HLA sensitization, with strategies combining plasma exchange, intravenous immunoglobulin and immune cell depletion, or with emerging or innovative therapies such as imlifidase or immunoadsorption. In cases of insufficient pre-transplant desensitization, the effects of antibodies on the allograft can be prevented by targeting the complement cascade, although evidence for this strategy in LT is limited. In LT recipients with a humoral response, strategies are combined, including depletion of immune cells (plasmapheresis or immunoadsorption), inhibition of immune pathways, or modulation of the inflammatory cascade, which can be achieved with photopheresis. Altogether, these innovative techniques offer promising perspectives for LT recipients and shape the 21st century's armamentarium against AMR. [ABSTRACT FROM AUTHOR]

Static cold storage (SCS) remains the gold standard for preserving donor hearts before transplantation but is associated with ischaemia, anaerobic metabolism, and organ injuries, leading to patient morbidity and mortality. We aimed to evaluate whether continuous, hypothermic oxygenated machine perfusion (HOPE) of the donor heart is safe and superior compared with SCS. We performed a multinational, multicentre, randomised, controlled, open-label clinical trial with a superiority design at 15 transplant centres across eight European countries. Adult candidates for heart transplantation were eligible and randomly assigned in a 1:1 ratio. Donor inclusion criteria were age 18–70 years with no previous sternotomy and donation after brain death. In the treatment group, the preservation protocol involved the use of a portable machine perfusion system ensuring HOPE of the resting donor heart. The donor hearts in the control group underwent ischaemic SCS according to standard practices. The primary outcome was time to first event of a composite of either cardiac-related death, moderate or severe primary graft dysfunction (PGD) of the left ventricle, PGD of the right ventricle, acute cellular rejection at least grade 2R, or graft failure (with use of mechanical circulatory support or re-transplantation) within 30 days after transplantation. We included all patients who were randomly assigned, fulfilled inclusion and exclusion criteria, and received a transplant in the primary analysis and all patients who were randomly assigned and received a transplant in the safety analyses. This trial was registered with ClicalTrials.gov (NCT03991923) and is ongoing. A total of 229 patients were enrolled between Nov 25, 2020, and May 19, 2023. The primary analysis population included 204 patients who received a transplant. There were no patients who received a transplant lost to follow-up. All 100 donor hearts preserved with HOPE were transplantable after perfusion. The primary endpoint was registered in 19 (19%) of 101 patients in the HOPE group and 31 (30%) of 103 patients in the SCS group, corresponding to a risk reduction of 44% (hazard ratio 0·56; 95% CI 0·32–0·99; log-rank test p=0·059). PGD was the primary outcome event in 11 (11%) patients in the HOPE group and 29 (28%) in the SCS group (risk ratio 0·39; 95% CI 0·20–0·73). In the HOPE group, 63 (65%) patients had a reported serious adverse event (158 events) versus 87 (70%; 222 events) in the SCS group. Major adverse cardiac transplant events were reported in 18 (18%) and 33 (32%) patients in the HOPE and SCS group (risk ratio 0·56; 95% CI 0·34–0·92). Although there was not a significant difference in the primary endpoint, the 44% risk reduction associated with HOPE was suggested to be a clinically meaningful benefit. Post-transplant complications, measured as major adverse cardiac transplant events, were reduced. Analysis of secondary outcomes suggested that HOPE was beneficial in reducing primary graft dysfunction. HOPE in donor heart preservation addresses the existing challenges associated with graft preservation and the increasing complexity of donors and heart transplantation recipients. Future investigation will help to further elucidate the benefit of HOPE. XVIVO Perfusion. [ABSTRACT FROM AUTHOR]

Tolerance of mouse kidney allografts arises in grafts that develop regulatory tertiary lymphoid organs (rTLOs). Single-cell RNA-seq (scRNA-seq) data and adoptive transfer of alloreactive T cells after transplantation showed that cytotoxic CD8+ T cells are reprogrammed within the accepted graft to an exhausted/regulatory-like phenotype mediated by IFN-γ. Establishment of rTLOs was required because adoptive transfer of alloreactive T cells prior to transplantation results in kidney allograft rejection. Despite the presence of intragraft CD8+ cells with a regulatory phenotype, they were not essential for the induction and maintenance of kidney allograft tolerance since renal allotransplantation into CD8-KO recipients resulted in acceptance and not rejection. Analysis of scRNA-seq data from allograft kidneys and malignant tumors identified similar regulatory-like cell types within the T cell clusters and trajectory analysis showed that cytotoxic CD8+ T cells are reprogrammed into an exhausted/regulatory-like phenotype intratumorally. Induction of cytotoxic CD8+ T cell dysfunction of infiltrating cells appears to be a beneficial mechanistic pathway that protects the kidney allotransplant from rejection through a process we call "defensive tolerance." This pathway has implications for our understanding of allotransplant tolerance and tumor resistance to host immunity. [ABSTRACT FROM AUTHOR]

Antibody-mediated rejection (AMR) is among the most frequent causes for graft loss after kidney transplantation. While there are no approved therapies, several case reports with daratumumab and the very recent phase 2 trial of felzartamab in AMR have indicated the potential efficacy of therapeutic interventions targeting CD38. Donor-derived cell-free DNA (ddcfDNA) is an emerging biomarker with injury-specific release and a short half-life, which could facilitate early diagnosis of AMR andmonitoring of treatment response. We describe two cases of patients with chronic active AMR, who were treated with monthly daratumumab infusions, and in whom donor-derived cell-free DNA (dd-cfDNA) was measured longitudinally to monitor treatment response. In both patients, daratumumab treatment led to stabilization of kidney function parameters, a strong decline of dd-cfDNA below the previously established threshold for rejection, and partial or complete histologic resolution of AMR activity. Our case series suggests that dd-cfDNA may be a useful companion biomarker for longitudinal monitoring of anti-CD38 treatment in patients with AMR. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Infection remains a relevant complication after kidney transplantation (KT). A well‐established strategy in modern medicine is the application of bundles of evidence‐based practice in clinical settings. The objective of this study is to explore the application of a personalized bundle of measures aimed to reduce the incidence of infection in the first 12 months after KT.A single‐center prospective cohort of 148 patients undergoing KT between February 2018 and September 2019 that received an individualized infection prevention strategy was compared to a preintervention cohort (n = 159). The bundle comprised a review of the patient's immunization history, infection risk by country of origin, screening for latent tuberculosis infection (LTBI), antimicrobial prophylaxis, and immunological assessment. Individualized recommendations were accordingly provided at a scheduled visit at day +30 after transplantation.The intervention cohort showed a higher compliance rate with the recommended vaccine schedule, screening for geographically restricted infections and LTBI, and intravenous immunoglobulin and vitamin D supplementation (p values <.001). The 1‐year incidence rate of infection was lower in the intervention cohort (42.6% vs. 57.9%; p value = .037), as was the rate of infection‐related hospitalization (17.6% vs. 32.1%; p value = .003) and the incidence of severe bacterial infection. There were no differences in graft rejection or mortality rates between groups.A multifaceted intervention, including a bundle of evidence‐based practices, enhanced compliance with recommended preventive measures and was correlated with a reduction in the 12‐month incidence of infection after KT. [ABSTRACT FROM AUTHOR]

Background: Pre-transplant donor-specific anti-human leukocyte antigen antibody (HLA-DSA) is a recognized risk factor for acute antibody-mediated rejection (ABMR) and allograft failure. However, the clinical relevance of pre- transplant crossmatch (XM)-negative HLA-DSA remains unclear. Methods: We investigated the effect of XM-negative HLA-DSA on post- transplant clinical outcomes using data from the Korean Organ Transplantation Registry (KOTRY). This study included 2019 living donor kidney transplant recipients from 40 transplant centers in South Korea: 237 with HLA-DSA and 1782 without HLA-DSA. Results: ABMR developed more frequently in patients with HLA-DSA than in those without (5.5% vs. 1.5%, p<0.0001). Multivariable analysis identified HLA-DSA as a significant risk factor for ABMR (odds ratio = 3.912, 95% confidence interval = 1.831-8.360; p<0.0001). Furthermore, the presence of multiple HLA-DSAs, carrying both class I and II HLA-DSAs, or having strong HLA-DSA were associated with an increased incidence of ABMR. However, HLA-DSA did not affect long-term clinical outcomes, such as allograft function and allograft survival, patient survival, and infection-free survival. Conclusion: Pre-transplant XM-negative HLA-DSA increased the risk of ABMR but did not affect long-term allograft outcomes. HLA-incompatible kidney transplantation in the context of XM-negative HLA-DSA appears to be feasible with careful monitoring and ensuring appropriate management of any occurrence of ABMR. Furthermore, considering the characteristics of pre-transplant XM-negative HLA-DSA, the development of a more detailed and standardized desensitization protocol is warranted. [ABSTRACT FROM AUTHOR]

Background: Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by diffuse, multifocal segmental narrowing of cerebral arteries and can result in ischaemic stroke. Causal factors, identified in 60% of cases, include immunosuppressant pharmacotherapy. The few reports following heart transplantation are almost all in Asian recipients. We report on a Caucasian Australian patient with immunotherapy induced RCVS post heart transplantation to highlight the state of knowledge of the condition and the treatment dilemma it poses. Case presentation: A 51-year-old female underwent orthotopic heart transplantation at our institution. Induction immunotherapy comprised basiliximab, mycophenolate mofetil and methylprednisolone. On day 6 post-transplantation the patient was transitioned to oral prednisolone and tacrolimus. On day 7 the patient began to experience bilateral, severe, transient occipital and temporal headaches. On day 9 tacrolimus dose was up-titrated. A non-contrast computed tomography brain (CTB) was normal. Endomyocardial biopsy on day 12 demonstrated moderate Acute Cellular Rejection (ACR), which was treated with intravenous methylprednisolone. That evening the patient experienced a 15-minute episode of expressive dysphasia. The following morning she became confused, aphasic, and demonstrated right sided neglect and right hemianopia. A CT cerebral perfusion scan demonstrated hypoperfusion in the left middle cerebral artery (MCA) territory and cerebral angiography revealed widespread, focal multi-segmental narrowing of the anterior and posterior circulations. A diagnosis of RCVS was made, and nimodipine was commenced. As both steroids and tacrolimus are potential triggers of RCVS, cyclosporin replaced tacrolimus and methylprednisolone dose was reduced. A further CTB demonstrated a large left MCA territory infarct with left M2 MCA occlusion. The patient made steady neurological improvement. She was discharged 34 days post-transplantation with mild residual right lower limb weakness and persistent visual field defect on verapamil, cyclosporine, everolimus, mycophenolate mofetil and prednisolone. Conclusion: Reversible cerebral vasoconstriction syndrome is rare after orthotopic heart transplantation. Until now, RCVS has been almost exclusively described in Asian recipients, and is typically caused by immunotherapy. The condition may lead to permanent neurological deficits, and in the absence of definitive treatments, early recognition and imaging based diagnosis is essential to provide the opportunity to remove the causal agent(s). Co-existent ACR, can pose unique treatment difficulties. [ABSTRACT FROM AUTHOR]

Histologic evaluation of allograft biopsies after lung transplantation has several limitations, suggesting that molecular assessment using tissue transcriptomics could improve biopsy interpretation. This single-center, retrospective cohort study evaluated discrepancies between the histology of transbronchial biopsies (TBBs) with no rejection (NR) and T-cell mediated rejection (TCMR) by molecular diagnosis. The accuracy of diagnosis was assessed based on response to treatment. 54 TBBs from Prague Lung Transplant Program obtained between December 2015 and January 2020 were included. Patients with acute cellular rejection (ACR) grade = 1 by histology received anti-rejection treatment. Response to therapy was defined as an increase in FEV1 of = 10% 4 weeks post-biopsy compared to the pre-biopsy value. Among the 54 analyzed TBBs, 25 (46%) were concordant with histology, while 29 (54%) showed discrepancies. ACR grade 0 was found in 12 TBBs (22%) and grade A1 = 1 in 42 TBBs (78%). Treatment response was present in 14% in the NR group and in 50% in the TCMR group (p = 0.024). Our findings suggest that low-grade acute cellular rejection is less likely to be associated with molecular TCMR, which might better identify lung transplant recipients who benefit from therapy. [ABSTRACT FROM AUTHOR]

We have previously reported that nanoparticles (NPs) loaded with IL-2 and TGF-β and targeted to T cells induced polyclonal T regulatory cells (Tregs) that protected mice from graft-versus-host disease (GvHD). Here, we evaluated whether administration of these NPs during alloantigen immunization could prevent allograft rejection by converting immunogenic responses to tolerogenic ones. Using C57BL/6 mice and BALB/c mice as either donors or recipients of allogeneic splenocytes, we found that treatment with the tolerogenic NPs in both strains of mice resulted in a marked inhibition of mixed lymphocyte reaction (MLR) to donor cell alloantigen but not to third-party control mouse cells after transfer of the allogeneic cells. The decreased alloreactivity associated with a four- to fivefold increase in the number of CD4+ and CD8+ T regulatory cells (Tregs) and the acquisition of a tolerogenic phenotype by recipient dendritic cells (DCs) in NP-treated mice. As allogeneic cells persisted in NP-treated mice, these findings suggest that tolerogenic NPs can induce alloantigen-specific Tregs and tolerogenic DCs promoting tolerogenic responses to alloantigen. By inhibiting reactivity to allotransplant, this approach could help reduce the need for immune suppression for the maintenance of allografts. [ABSTRACT FROM AUTHOR]

To minimize graft rejection, it is crucial to reduce immunosuppression. In the present study, we investigated immunological markers in the blood of transplant patients who did not receive tacrolimus. We also assessed alloreactive CD4+CD25+FoxP3+ Tregs both before transplantation and after tacrolimus reduction. The comparative analysis included 50 individuals experiencing early rejection after tacrolimus discontinuation and 100 non-rejectors. Before reducing tacrolimus, rejectors exhibited elevated levels of memory CD8+ T cells compared to Tregs, while non-rejectors displayed a lower ratio of memory CD4+ T cells to Tregs. Following tacrolimus removal, rejectors showed an increase in naïve T cells and a decrease in effector T cells. After transplantation, CD4+ Treg levels declined, but their anti-donor regulatory function remained consistent in both rejectors and non-rejectors. Immunological correlation revealed an association between acute rejection after tacrolimus discontinuation and the pre-reduction ratio of memory T cells to regulatory T cells. These indicators identified individuals whose immunosuppression could be safely reduced. [ABSTRACT FROM AUTHOR]

Background: Corneal inflammatory hem- and lymphangiogenesis significantly increase the risk for immune rejection after subsequent allogeneic corneal transplantation. The purpose of this study was to analyze the impact of temporary selective inhibition of lymphangiogenesis after transplantation on graft survival. Methods: Allogeneic transplantation from C57BL/6 mice to BalbC mice was performed as "high-risk" keratoplasty in a prevascularized corneal host bed (suture-induced inflammatory corneal neovascularization). The treatment group received integrin α5β1-blocking small molecules (JSM6427) at the time of transplantation and for two weeks afterwards. Control mice received a vehicle solution. Grafts were evaluated weekly for graft rejection using an opacity score. At the end of the follow-up, immunohistochemical staining of corneal wholemounts for lymphatic vessels as well as CD11b+ immune cells was performed. Results: Temporary postoperative inhibition of lymphangiogenesis by JSM6427 improved the corneal graft survival significantly. At the end of the follow-up, no significant reduction in CD11b+ immunoreactive cells within the graft compared to controls was found. Conclusions: The significant improvement of corneal graft survival by the selective, temporary postoperative inhibition of lymphangiogenesis after keratoplasty using integrin antagonists shows the impact of lymphatic vessels in the early postoperative phase. Retarding lymphatic vessel ingrowth into the graft might be sufficient for the shift to immunological tolerance in the postoperative period, even after high-risk keratoplasty. [ABSTRACT FROM AUTHOR]

The QuantiFERON CMV (QCMV) test evaluates specific adaptive immune system activity against CMV by measuring IFN-γ released by activated CD8+ T lymphocytes. We aimed to evaluate the QCMV test as a predictive tool for CMV manifestations and acute or chronic lung allograft rejection (AR and CLAD) in lung transplant (LTx) patients. A total of 73 patients were divided into four groups based on donor and recipient (D/R) serology for CMV and QCMV assay: group A low-risk for CMV infection and disease (D−/R−); group B and C at intermediate-risk (R+), group B with non-reactive QCMV and group C with reactive QCMV; group D at high-risk (D+/R−). Group D patients experienced higher viral replication; no differences were observed among R+ patients of groups B and C. D+/R− patients had a higher number of AR events and group C presented a lower incidence of AR. Prevalence of CLAD at 24 months was higher in group B with a higher risk of CLAD development (OR 6.33). The QCMV test allows us to identify R+ non-reactive QCMV population as the most exposed to onset of CLAD. This population had a higher, although non-significant, susceptibility to AR compared to the R+ population with reactive QCMV. [ABSTRACT FROM AUTHOR]

Intestinal transplantation is a complex technical procedure that provides patients suffering from end-stage intestinal failure an opportunity to enjoy improved quality of life, nutrition and survival. Compared to other types of organ transplants, it is a relatively new advancement in the field of organ transplantation. Nevertheless, great advances have been made over the past few decades to the present era, including the use of ischemic preconditioning, gene therapy, and addition of pharmacological supplements to preservation solutions. However, despite these strides, intestinal transplantation is still a challenging endeavor due to several factors. Notable among them is ischemia-reperfusion injury (IRI), which results in loss of cellular integrity and mucosal barrier function. In addition, IRI causes graft failure, delayed graft function, and decreased graft and recipient survival. This has necessitated the search for novel therapeutic avenues and improved transplantation protocols to prevent or attenuate intestinal IRI. Among the many candidate agents that are being investigated to combat IRI and its associated complications, nitric oxide (NO). NO is an endogenously produced gaseous signaling molecule with several therapeutic properties. The purpose of this mini-review is to discuss IRI and its related complications in intestinal transplantation, and NO as an emerging pharmacological tool against this challenging pathological condition. i • Cold preservation and engraftment induces ischemia-reperfusion injury IRI. • Nitric oxide produced by iNOS exerts detrimental effect on intestinal grafts. • Nitric oxide donors protect intestinal grafts against IRI and associated complications. • Nitric oxide prevents acute graft rejection after intestinal transplantation. • Endogenous nitric oxide protects intestinal mucosal barrier function. [ABSTRACT FROM AUTHOR]

Pediatric heart transplantation is hampered by a chronic shortage of donor organs. This problem is further confounded by graft rejection. Identification of earlier indicators of pediatric graft rejection and development of subsequent strategies to counteract these effects will increase the longevity of transplanted pediatric hearts. Heart transplant reject is due to a complex series of events, resulting in CAV, which is thought to be mediated through a host immune response. However, the earlier events leading to CAV are not very well known. We hypothesize that early events related to ischemia reperfusion injury during pediatric heart transplantation are responsible for CAV and subsequent graft rejection. Identification of the molecular markers of ischemia reperfusion injury and development of subsequent therapies to block these pathways can potentially lead to a therapeutic strategy to reduce CAV and increase the longevity of the transplanted heart. To accomplish this goal, we have developed a perfusable vascular graft model populated with endothelial cells and demonstrated the feasibility of this model to understand the early events of ischemia reperfusion injury. [ABSTRACT FROM AUTHOR]

Transplantation of human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) has emerged as a promising therapy to treat end-stage heart failure. However, the immunogenicity of hiPS-CMs in transplanted patients has not been fully elucidated. Thus, in vivo models are required to estimate immune responses against hiPS-CMs in transplant recipients. We transferred human peripheral blood mononuclear cells (hPBMCs) into NOD/Shi- scid IL-2rg null (NOG) MHC class I/II double knockout (NOG-ΔMHC) mice, which were reported to accept hPBMCs without xenogeneic-graft- versus -host disease (xeno-GVHD). Then, hiPS-CM sheets generated from the hiPS cell line 201B7 harboring a luciferase transgene were transplanted into the subcutaneous space of NOG-ΔMHC mice. Graft survival was monitored by bioluminescent images using a Xenogen In Vivo Imaging System. The human immune cells were engrafted for more than 3 months in NOG-ΔMHC mice without lethal xeno-GVHD. The hiPS-CMs expressed a moderate level of human leukocyte antigen (HLA)-class I, but not HLA-class II, molecules even after interferon-gamma (IFN-γ) stimulation. Consistently, the allogenic IFN-γ-treated hiPS-CMs induced weak CD8+ but not CD4+ T cell responses in vitro. hiPS-CM sheets disappeared approximately 17 to 24 days after transplantation in hPBMC-transferred NOG-ΔMHC mice, and CD8+ T cell depletion significantly prolonged graft survival, similar to what was observed following tacrolimus treatment. hiPS-CMs are less immunogenic in vitro but induce sufficient CD8+ T cell-mediated immune responses for graft rejection in vivo. [ABSTRACT FROM AUTHOR]

Several reports have highlighted the dichotomous nature of the Interleukin-33 (IL-33) system in cardiac and lung disease, where this cytokine can exert both protective effects and drive pro-inflammatory responses in a context-specific manner. This State-of-the-Art review focuses on preclinical mechanistic studies of the IL-33 system in development of allograft rejection in heart and lung transplantation. We address the scope of potential cellular sources of IL-33 and pathways for cellular release that may impact the study of this cytokine system in transplant models. We then highlight soluble IL-33 receptor as a biomarker in cardiac allograft rejection and detail preclinical models that collectively demonstrate a role for this cytokine in driving type-2 immune programs to protect cardiac allografts. We contrast this with investigation of IL-33 in lung transplantation, which has yielded mixed and somewhat conflicting results when comparing human studies with preclinical models, which have implicated the IL-33 system in both allograft tolerance and acceleration of chronic rejection. We summarize and interpret these results in aggregate and provide future directions for study of IL-33 in heart and lung transplantation. [Display omitted] [ABSTRACT FROM AUTHOR]

Introduction: Uterus transplantation (UTx) is a novel treatment for absolute uterine infertility. Acute T cell–mediated rejection (TCMR) can be monitored only through serial cervical biopsies. Methods: This study, the first of its kind in human transplantation, evaluated clinical, serological, and pathophysiological manifestations of allograft rejection from immunosuppression withdrawal (ISW) to graft hysterectomy (Hx). Results: Following live birth, immunosuppression was abruptly withdrawn from six living‐donor UTx recipients. ISW occurred at a median of 7.4 weeks before graft Hx. Post‐ISW signs of rejection included: (1) discoloration of the cervix; (2) increased uterine size compared to day of ISW; (3) serological evidence of eosinophilia and progressive development of donor‐specific antibodies (DSA) or child‐specific antibodies (CSA); (4) histopathological evidence of TCMR in cervical biopsies preceding the development of antibodies in serum; and (5) C4d deposition in tissue before formation of DSA or CSA in all but two recipients. At graft Hx, endometrial glands were preferentially targeted for destruction over stroma while parametrial arteries displayed variable arteritis and fibrointimal hyperplasia. Conclusion: Recognition of the progression of uterine allograft rejection may be important for other human organ recipients and drive research on modulation of immunosuppression and the paradoxical relationship between adaptive cellular and humoral immunity in natural pregnancies. Trial Registration: ClinicalTrials.gov identifier: NCT02656550 [ABSTRACT FROM AUTHOR]

Background: Epstein–Barr virus (EBV) is a herpesvirus linked to nine different human tumors and lymphoproliferative disorders. Immunosuppression promotes EBV‐driven malignancies. The most frequent EBV‐induced malignancies are lymphomas and nasopharyngeal carcinoma. By promoting smooth muscle proliferation, EBV can induce EBV‐associated smooth muscle tumors (EBV‐SMT). EBV‐SMT is a rare oncological entity for which no current guideline for diagnosis or management exists. Data on posttransplant EBV‐SMT (PT‐SMT) are scarce in kidney transplant recipients. Methods: We conducted a national multicentric retrospective study and collected cases among transplantation centers in France. Kidney transplant recipients experiencing histologically proven PT‐SMT were included. We collected data on demographic characteristics of patient, history of kidney transplantation, history of PT‐SMT, evolution of graft function, and patient survival. Results: Eight patients were included. The median age at PT‐SMT diagnosis was 31 years (range 6.5–40). PT‐SMT occurred after a median delay of 37.8 months after transplantation (range 6–175). PT‐SMT management consisted in immunosuppressive regimen minimization in all patients. Introduction of mTOR inhibitors was performed in two patients. Four patients (50%) needed chemotherapy. Surgical resection was performed in four patients. At last follow‐up after PT‐SMT diagnosis (median 33 months (range 17–132)), five patients were considered in complete remission, and two patients had died. Two patients experienced graft rejection; two resumed dialysis (25%). All patients with available data presented with impaired graft function at last follow‐up. Conclusion: PT‐SMT is a subacute and progressive disease during kidney transplantation. Even if the risk of developing PT‐SMT is low in kidney transplant recipients (0.07% in our cohort), PT‐SMT is associated with significant graft loss, possibly due to reduced immunosuppression. Developing guidelines could help transplantation teams better manage these patients. [ABSTRACT FROM AUTHOR]

(1) Background: We aimed to investigate the outcomes of human leukocyte antigen (HLA)-incompatible transplantation for patients who received desensitization with intravenous immunoglobulins (IVIg), plasmapheresis, and rituximab. (2) Methods: A comprehensive search of multiple electronic databases to identify studies that utilized desensitization was conducted. The random-effects model was used to calculate the pooled rates and the 95% confidence interval (CI). (3) Results: A total of 1517 studies were initially identified. From these, 16 studies met the inclusion criteria, encompassing 459 patients, with a mean age of 45 years, of whom 40.8% were male. CDC crossmatch was positive in 68.3% (95% CI: 43.5–85.8; I2 87%), and 89.4% (95% CI: 53.4–98.4%; I2 89.8%) underwent living-donor transplantation. The 1-year graft survival pooled rate was 88.9% (95% CI: 84.8–92; I2 0%) and the 5-year graft survival rate was 86.1% (95% CI: 81.2–89.9; I2 0%). The 1-year patient survival rate was 94.2% (95% CI: 91–96.3; I2 0%), and the 5-year patient survival rate was 88.9% (95% CI: 83.5–92.7%; I2 7.7%). The rate of antibody-mediated rejection was 37.7% (95% CI: 25–52.3; I2 80.3%), and the rate of acute cell-mediated rejection was 15.1% (95% CI: 9.1–24; I2 55%). (4) Conclusions: Graft and patient survival are favorable in highly sensitized patients who undergo desensitization using IVIg, plasmapheresis, and rituximab for HLA-incompatible transplantation. [ABSTRACT FROM AUTHOR]

Background: Therapeutic apheresis (TA) is already used to treat various diseases in the field of nephrology. The aim of this study was to evaluate the frequency and types of complications that occur during TA in children with kidney disease. Methods: Records of children (≤ 18 years) who underwent TA between 2007 and 2022 were retrospectively reviewed. Children with missing data and those with a diagnosis of nonnephrological disease were excluded. Results: A total of 1214 TA sessions, including 1147 therapeutic plasma exchange (TPE) sessions and 67 immunoadsorption (IA) sessions, were performed on the 108 patients enrolled in the study. Forty-seven percent of the patients were male, and the mean age was 12.22 ± 4.47 years. Posttransplant antibody-mediated rejection (64.8%) and hemolytic uremic syndrome (14.8%) were the most common diagnoses indicating TA. Overall, 17 different complications occurred in 58 sessions (4.8%), and 53 sessions (4.6%) were not completed because of these complications. The distribution of complications among the patients was as follows: 41.4% had technical complications, 25.9% had allergic complications, and 32.7% had others. The most common technical complication was insufficient flow (37.5%). The incidence of complications was greater in patients aged 3–6 years than in patients in the other age groups (p = 0.031). The primary disease, type of vascular access, and rate of fresh frozen plasma/albumin use were similar between patients with and without complications (p values of 0.359 and 0.125 and 0.118, respectively). Conclusions: Our study showed that complications occurred in only 4.8% of TA sessions. The most common complication was technical problems. [ABSTRACT FROM AUTHOR]

Background: Neutropenia is a common complication in lung transplant recipients (LTRs). Filgrastim may be used to treat neutropenia in LTRs, but its consequences on acute cellular rejection (ACR) remain controversial. Objective: The purpose was to examine the association between filgrastim and incidence of ACR 6 months after filgrastim administration in LTRs. Secondary outcomes included burden of ACR, infections, chronic lung allograft dysfunction (CLAD), and survival. Methods: This was a matched cohort study of patients transplanted between January 2010 and October 2019. LTRs who received filgrastim for neutropenia were compared to a cohort who did not. LTRs were matched on transplant indication, sex, age, and time post-transplant and multivariable logistic regression models were used to evaluate the likelihood of ACR. Results: 212 patients were included in the analysis (106 in each group). 50 patients (47.2%) in the filgrastim group experienced ACR compared to 37 patients (34.9%) in the no filgrastim group (P =.070). In multivariable analysis, filgrastim use was not associated with ACR at 6 months (OR 1.409, 95% CI 0.772-2.571). Time to first ACR was shorter (P =.049) and 6-month ACR score was higher in the filgrastim group (.49 vs.33, P =.047). LTRs in the filgrastim group had higher incidence of bacterial pneumonia and 1-year mortality. Conclusions: Although not associated with increased likelihood of ACR at 6 months, our study found that filgrastim is associated with increased ACR burden and decreased time to ACR. This study can help inform clinicians of ACR risk after filgrastim use in LTRs. [ABSTRACT FROM AUTHOR]

Background: Antibody‐mediated rejection is one of the most significant risk factors for allograft dysfunction and failure in children and adolescents with kidney transplants, yet optimal treatment remains unidentified. To date, there are mixed findings regarding the use of Bortezomib, a plasma cell apoptosis inducer, as an adjunct therapy in the treatment of antibody‐mediated rejection. Methods: In a retrospective single center study, we reviewed the efficacy and tolerability of bortezomib as adjunct therapy for treatment‐refractory antibody‐mediated rejection. Results: Six patients with a median age of 14.6 years (range 6.9–20.1 years) received bortezomib at a mean of 71 months (range 15–83 months) post‐kidney transplant. Four patients experienced decline in estimated glomerular filtration rate (eGFR) from 4% to 42%. One patient started bortezomib while on hemodialysis and did not recover graft function, and another patient progressed to hemodialysis 6 months after receiving bortezomib. Although DSA did not completely resolve, there was a statistically significant decline in DSA MFI pre and 12‐months post‐BZ (p =.012, paired t‐test) for the subjects who were not on dialysis at the time of bortezomib. Chronic Allograft Damage Index (CADI) score of ≥3 was seen in all six subjects at their biopsy prior to therapy. No adverse effects were reported. Conclusions: Bortezomib was well tolerated and resulted in improvements in MFI of DSA among four pediatric subjects without allograft failure, although no effects were observed on eGFR trajectory. Further studies are needed to clarify whether earlier intervention with bortezomib could prevent renal failure progression. [ABSTRACT FROM AUTHOR]

Background: BK polyomavirus (BKV) DNAemia is a challenging infectious complication after kidney transplant (KT). Reduction of immunosuppression is the mainstay of management, and tacrolimus is often the first immunosuppressive medication adjusted upon the diagnosis of BKV DNAemia. This study aimed to evaluate the impact of a new institutional protocol with lower target tacrolimus levels on BKV DNAemia, allograft rejection, and de novo donor‐specific antibodies (dnDSA) among pediatric KT recipients. Methods: We conducted a retrospective chart review of all KT episodes between January 2013 and December 2018. The new protocol with lower target tacrolimus levels was implemented in March 2015. One hundred twenty‐seven patients were included in primary analysis. All patients received induction with basiliximab and methylprednisolone and were maintained on a steroid‐based immunosuppressive regimen. Results: In the post‐intervention cohort, cumulative incidence of BKV DNAemia at 100 days (13.4% vs. 17.8%, p =.605) and 18 months post‐KT (34.1% vs. 26.7%, p =.504) was not significantly different from the pre‐intervention cohort. Biopsy‐proven rejection rate did not change. However, we observed a trend toward earlier development of dnDSA in the post‐intervention cohort using the Kaplan–Meier survival analysis (log‐rank p =.06). Younger recipient age at the time of transplant was found to slightly increase the risk of BKV DNAemia (OR: 1.09, 95% CI [1.01, 1.16], p =.024). There was an association between BKV DNAemia and biopsy‐proven rejection of any type (adjustedOR: 2.77, 95% CI [1.26, 6.23], p =.012), especially acute T‐cell‐mediated rejection grade 1A and above (adjustedOR: 2.95, 95% CI [1.06, 8.30], p =.037), after adjusted for recipient age at the time of transplant. Conclusions: Targeting lower tacrolimus levels did not decrease the incidence of BKV DNAemia within 100 days or 18 months post‐KT, nor did it increase the risk of biopsy‐proven rejection among pediatric KT recipients in our center. However, there was a trend toward earlier development of dnDSA, which may portend worse long‐term graft outcome post‐KT. Our findings highlight the need for individualized immunosuppressive regimens based on immunologic and infectious risk factors and the importance of implementing innovative biomarkers to guide therapy and improve outcomes. [ABSTRACT FROM AUTHOR]

The implications of impaired esophagogastric junction relaxation (i.e. esophagogastric junction outflow obstruction and achalasia) in lung transplants recipients (LTRs) are unclear. Thus, we examined the prevalence and clinical outcomes of LTRs with an abnormally elevated integrated relaxation pressure (IRP) on high-resolution manometry before lung transplantation (LTx). After IRB approval, we reviewed data on LTRs who underwent LTx between January 2019 and August 2022 with a preoperative median IRP >15 mmHg. Differences in overall survival and chronic lung allograft dysfunction (CLAD)–free survival between LTRs with a normalized median IRP after LTx (N-IRP) and those with persistently high IRP (PH-IRP) were assessed using Kaplan–Meier curves and the log-rank test. During the study period, 352 LTx procedures were performed; 44 (12.5%) LTRs had an elevated IRP before LTx, and 37 (84.1%) completed a postoperative manometry assessment (24 [70.6%] males; mean age, 65.2 ± 9.1 years). The median IRP before and after LTx was 18.7 ± 3.8 mmHg and 12 ± 5.6 mmHg, respectively (P  < 0.001); the median IRP normalized after LTx in 24 (64.9%) patients. Two-year overall survival trended lower in the N-IRP group than the PH-IRP group (77.2% vs. 92.3%, P =  0.086), but CLAD-free survival (P =  0.592) and rates of primary graft dysfunction (P =  0.502) and acute cellular rejection (P =  0.408) were similar. An abnormally elevated IRP was common in LTx candidates; however, it normalized in roughly two-thirds of patients after LTx. Two-year survival trended higher in the PH-IRP group, despite similar rates of primary graft dysfunction and acute cellular rejection as well as similar CLAD-free survival between the groups. [ABSTRACT FROM AUTHOR]

This study examines the interplay between human leukocyte antigen (HLA) compatibility and killer-cell immunoglobulin-like receptor (KIR) genotypes in influencing kidney transplantation outcomes. Understanding these interactions is crucial for improving graft survival and minimizing rejection risks. We evaluated 84 kidney transplant recipients, dividing them into two groups based on post-transplant outcomes: there were 68 with stable graft function (SGF) and 16 who experienced chronic rejection (CR). Patients were selected based on specific inclusion criteria. HLA mismatches (Class I: HLA-A, -B; Class II: HLA-DR) and KIR genotypes were determined using standard genotyping techniques. Statistical analyses, including logistic regression, were performed to correlate these factors with transplant outcomes. Significant age differences were observed, with younger patients more likely to experience graft rejection, while no significant gender-based differences were noted. A significant correlation was found between Class II mismatches and increased rejection rates, highlighting the importance of HLA-DR compatibility. Further analysis revealed that certain inhibitory KIRs, such as KIR3DL1, were associated with favorable outcomes, suggesting a protective role against graft rejection. These findings were corroborated by evaluating serum creatinine levels over multiple years, serving as a biomarker for renal function post transplant. This study underscores the critical need for meticulous HLA matching and the consideration of KIR genotypes in pre-transplant evaluations to enhance graft survival and minimize rejection risks. Integrating these genetic factors into routine clinical assessments could significantly improve personalized transplant medicine strategies, ultimately enhancing patient outcomes. Further research is needed to explore the underlying mechanisms and validate these findings in larger, diverse populations. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Bone marrow transplantation (BMT) saves lives in Omenn syndrome, a severe immunodeficiency disorder. Timely genetic diagnosis and matched donor BMT are crucial. Emphasis on newborn screening and multidisciplinary care improves outcomes for infants with inherited disorders. Prompt intervention and comprehensive management are vital for a successful transplant outcome. Omenn syndrome represents a severe variant of combined immunodeficiency characterized by disregulated immune responses and susceptibility to recurrent infections. We present the case of a 3‐month‐old female infant initially presenting with upper respiratory infection symptoms and a diffuse rash, unresponsive to local treatment. At 4 months of age, the patient underwent allogeneic bone marrow transplantation (BMT) utilizing stem cells from a fully matched sibling donor. Pre‐transplant conditioning included antimicrobial prophylaxis and supportive therapies. Following BMT, the patient received immunosuppressive medications to prevent graft rejection and graft‐versus‐host disease. Clinical monitoring post‐transplant showed timely neutrophil and platelet engraftment, with subsequent follow‐up demonstrating stable clinical parameters and negative cytomegalovirus status. The case highlights the importance of timely diagnosis and treatment in managing severe immunodeficiency disorders, demonstrating the potential for successful outcomes with appropriate timely interventions. Regular monitoring and follow‐up appointments were crucial in ensuring the success of the treatment. This case also emphasizes the significance of multidisciplinary care and genetic testing in identifying and managing rare immunodeficiency disorders. The successful outcome in this case provides hope for improved treatment options and better patient outcomes in the future. [ABSTRACT FROM AUTHOR]

Introduction: Acquired amyloid neuropathy is an iatrogenic disease that appears years after a domino liver transplant. The objectives of our study are to analyze the efficacy and tolerability of tafamidis for the treatment of acquired amyloid neuropathy in domino liver transplant recipients. This post-authorization, prospective, longitudinal study included seven domino liver transplant recipients with acquired amyloid neuropathy who received treatment with tafamidis for 18 months. Methods: The primary endpoints were the response rate, defined as those patients with an increase of < 2 points on the Neurological Impairment Score (NIS) from baseline, and the change in the NIS score from baseline. Secondary endpoints included the Quantitative Sensory Test, 10-m walk test, quality of life (Norfolk), and disability (Rasch-built Overall Disability Scale). As safety parameters, the evidence of graft rejection, changes in immunosuppressive trough levels and changes in antiviral and allogeneic cellular immunity before and 12 months after tafamidis treatment were also assessed. Results: Six patients (85.7%) had responded at 18-months. Compared to baseline, we observed non-statistically significant improvement in mean NIS score at 6 months (− 2.54 points, CI − 5.92 to 0.84), 12 months (− 3.25 points; CI − 6.63 to 0.13), and 18 months (− 2.35 points; CI − 5.74 to 1.02). Changes in the Quantitative Sensory Test, 10-m walk tests and the quality of life and disability questionnaires were not statistically significant. The use of tafamidis did not induce relevant side effects or drug interactions. Also, no acute rejections events nor changes in functional adaptive immunity were observed. Conclusion: Our study supports the safety and tolerability of tafamidis for the treatment of acquired amyloid neuropathy in domino liver transplant recipients. Tafamidis shows promise as a useful treatment in the clinical management of these patients. Future randomized placebo-controlled clinical trials with longer follow-up durations are needed. [ABSTRACT FROM AUTHOR]

To evaluate the co-transplantation efficacy of umbilical cord mesenchymal stem cells (UC-MSCs) and peripheral blood stem cells (PBSCs) as a novel approach for refractory or relapsed severe aplastic anemia (R/R SAA) in children and adolescents, thirty-two children and adolescents diagnosed with R/R SAA underwent a retrospective chart review. The patients were categorized into two groups based on the source of PBSCs: the matched sibling donor (MSD) group and the unrelated donor (UD) group. No adverse events related to UC-MSC infusion occurred in any of the patients. The median time for neutrophil engraftment was 13 days (range: 10–23 days), and for platelets, it was 15 days (range: 11–28 days). Acute GVHD of Grade I–II and moderate chronic GVHD were observed in 21.8 and 12.5% of cases, respectively. No statistically significant differences were found between the MSD and UD groups in terms of engraftment, GVHD, and complications, including infection and hemorrhagic cystitis. The median follow-up time was 38.6 months (range: 1.4–140.8 months). As of October 31, 2021, five patients had succumbed, while 27 (84.4%) survived. The 5-year OS rate showed no statistically significant difference between the MSD and UD groups (84.8 ± 10.0 vs. 82.4 ± 9.2%, p = 0.674). In conclusion, the application of UC-MSCs in the treatment of R/R SAA in PBSC transplantation is reliable and safe, they had no graft rejection, low incidence of severe GVHD which may have been contributed by the co-infusion of MSC. [ABSTRACT FROM AUTHOR]

Heart transplant prolongs life for patients with end-stage heart failure but rejection remains a complication that reduces long-term survival. The aim is to provide a comprehensive overview of the current status in HT rejection. EMB is an invasive diagnostic tool, consisting in the sampling of a fragment of myocardial tissue from the right ventricular septum using fluoroscopic guidance. This tissue can later be subjected to histopathological, immunohistochemical or molecular analysis, providing valuable information for cardiac allograft rejection, but this procedure is not without complications. To increase the accuracy of the rejection diagnosis, EMB requires a systematic evaluation of endocardium, myocardium, interstitium and intramural vessels. There are three types of rejection: hyperacute, acute or chronic, diagnosed by the histopathological evaluation of EMB as well as by new diagnostic methods such as DSA, ddcfDNA and gene expression profiling, the last having a high negative predictive value. More than 50 years after the introduction of EMB in medical practice, it still remains the "gold standard" in monitoring rejection in HT recipients but other new, less invasive diagnostic methods reduce the number of EMBs required. [ABSTRACT FROM AUTHOR]