A rare case of non-lupus full house nephropathy in a transplanted kidney, case report

Key Clinical Message

Non-lupus full house nephropathy is a rare entity that is still poorly understood. It can complicate post-transplant kidneys and result in a de novo process. Treatment is difficult but can be possibly achieved with optimization of immune suppression.

Abstract

Non-lupus full house nephropathy is a rare entity with an unclear incidence. It describes the kidney biopsy findings of positive deposits for IgG, IgA, IgM, C3, and C1q on immunofluorescence in the absence of the classical diagnostic features of systemic lupus nephritis. This disease entity is becoming more recognized but further studies are still needed to evaluate the incidence, etiologies, and management of this condition. Transplant glomerulopathy is a major cause for renal graft loss. It can present with a wide variety of manifestations; it can cause AKI, CKD, or glomerular inflammations through an immune complex or autoimmune-mediated damage.

Analysis on the change of gut microbiota and metabolome in lung transplant patients

Previous studies have shown that the gut microbiota and its metabolites are associated with the success of organ transplantation. However, the specific changes in the gut microbiota of lung transplant patients remain unclear. Hence, this study aimed to elucidate the interplay between the gut microbiota, metabolome, and lung transplantation outcomes. Using 16S metagenomics sequencing and untargeted metabolic profiling, we conducted a comprehensive analysis of gut microbial and metabolic alterations in lung transplant recipients relative to non-transplant group. Our findings revealed the predominance of Enterococcus and Streptococcus genera within the lung transplant cohort, accompanied by the significant reduction in Bacteroides, Epulopiscium, Faecalibacterium, and Prevotella abundance. In addition, a significant reduction in ATRA (all-trans retinoic acid) levels and suppression of IgA production were observed in lung transplant recipients, which were found to be closely associated with the Enterococcus genus. It was speculated that the association might have implications for the prognosis of lung transplant patients. Notably, the differences in gut microbial composition and metabolomic profiles between successful transplant recipients and those experiencing chronic rejection were not statistically significant. These novel insights shed light on the putative implications of the gut microbiota and metabolome in shaping lung transplantation outcomes, and provide a foundation for future investigations and targeted therapeutic interventions.

IMPORTANCE

This study has profound implications for lung transplantation as it uncovers the important role of gut microbiota and metabolome in shaping transplantation outcomes. The identification of dominant bacterial genera, such as Enterococcus and Streptococcus, within the lung transplant cohort, along with the significant decrease in Bacteroides, Epulopiscium, Faecalibacterium, and Prevotella abundance, reveals potential microbial imbalances associated with lung transplantation. In addition, a significant reduction in ATRA (all-trans retinoic acid) levels and suppression of IgA production were observed in lung transplant recipients, which were found to be closely associated with the Enterococcus genus. It was speculated that the association might have implications for the prognosis of lung transplant patients. These findings hold immense clinical significance as they lay the groundwork for future research and targeted therapeutic interventions. Understanding the impact of the gut microbiota and metabolome on lung transplantation outcomes offers promising avenues for improving transplantation patient prognosis.

Expression of a mutant CD47 protects against phagocytosis without inducing cell death or inhibiting angiogenesis

CD47 is a ligand of SIRPα, an inhibitory receptor expressed by macrophages, dendritic cells, and natural killer (NK) cells, and, therefore, transgenic overexpression of CD47 is considered an effective approach to inhibiting transplant rejection. However, the detrimental effect of CD47 signaling is overlooked when exploring this approach. Here, we construct a mutant CD47 by replacing the transmembrane and intracellular domains with a membrane anchor (CD47-IgV). In both human and mouse cells, CD47-IgV is efficiently expressed on the cell surface and protects against phagocytosis in vitro and in vivo but does not induce cell death or inhibit angiogenesis. Furthermore, hematopoietic stem cells expressing transgenic CD47-IgV show no detectable alterations in engraftment or differentiation. This study provides a potentially effective means of achieving transgenic CD47 expression that may help to produce gene-edited pigs for xenotransplantation and hypoimmunogenic pluripotent stem cells for regenerative medicine.

The role of the indoleamine 2,3-dioxygenase gene in preventing ovarian transplant rejection in rats

Indoleamine 2, 3-dioxygenase (IDO) plays important roles in maternal immune tolerance. Female Sprague Dawley rats (9-11 weeks old) were randomly divided into an autoplastic transplantation group (n = 75) and an allograft transplantation group (n = 300) further divided into subgroups of ovarian transplantation, allograft ovarian transplantation, allograft ovarian transplantation with cyclosporine A treatment, allograft ovarian transplantation and transfection with IDO-expressing lentiviruses, and allograft ovarian transplantation and transfection with control lentiviruses. IDO was successfully transfected intothe transplanted ovarian tissue. The survival rate, success rate of ovarian transplantation, period until estrous cycle restoration, and estrogen levels of rats that received IDO-expressing lentiviruseswere significantly different from those of rats that underwent allograft transplantation and with control transfection (all P < 0.05), but not significantly different from those of rats that received autoplastic transplantation (all P > 0.05). The number of ovarian follicles in the transplanted ovarian tissue of rats that received IDO-expressing lentiviruses was also significantly higher. The expression level of IDO protein detected by immunohistochemistry and western blotting was especially high in ovaries that had received IDO-containing lentiviruses. Naturally pregnant rats were found in each group postoperatively. These results indicate that IDO-expressing lentiviruses were successfully transfected into transplanted ovarian tissues of rats and that IDO was stably expressed within a certain time. These findings suggest that the expression level of IDO protein is associated with an enhanced success rate of ovarian tissue transplantation and a short restoration period of endocrine function.

Pancreatic Panniculitis: A Case Associated With Acute Pancreatic Allograft Rejection

We present a unique case of pancreatic panniculitis (PP) in a 42-year-old male with a history of pancreas-after-kidney (PAK) transplant. The patient developed PP due to acute pancreas allograft rejection. Clinical manifestations included fevers, myalgias, arthralgias, and tender erythematous subcutaneous nodules on the lower extremities. A recent hospital admission was noted for acute pancreas allograft rejection related to low tacrolimus levels. Rheumatological and infectious disease workups were negative. Skin nodule punch biopsy confirmed PP with lobular panniculitis, necrotic adipocytes, basophilic debris, and calcification. Pancreatic biopsy showed evidence of parenchymal acute cellular rejection. Lipase and amylase levels were elevated (1781 U/L and 881 U/L, respectively). Treatment involved pulse solumedrol and thymoglobulin for pancreatic rejection, alongside adjustments to immunosuppressive medications. This case highlights the rarity of PP in a PAK recipient and its association with acute pancreas allograft rejection. Importantly, it is the first reported case of PP occurring solely in the context of pancreas transplant rejection, without concurrent kidney damage or rejection. Prompt diagnosis and management led to the resolution of skin and systemic symptoms. In conclusion, this report presents a clinically relevant and unique case of PP resulting from acute pancreas allograft rejection in a PAK transplant recipient. The findings underscore the importance of early diagnosis and management for positive patient outcomes, serving as a reminder to consider underlying pancreatic pathology when encountering PP in transplant recipients.

Impact of Angiotensin Blockade on Development of Chronic Lung Allograft Dysfunction

Background: The renin-angiotensin-aldosterone system (RAAS) is responsible for a multitude of physiological functions, including immunological effects such as promotion of TGF-β and upregulation of IL-6 and IL-8 which are also implicated in the development of chronic lung allograft dysfunction (CLAD). Blockade of the RAAS pathway in pre-clinical models has demonstrated a decrease in these cytokines and pulmonary neutrophil recruitment. Objective: This study sought to evaluate whether use of RAAS inhibitor (RAASi) in lung transplant recipients impacted CLAD-free survival. Methods: In this retrospective, single-center study, 35 lung transplant recipients who received a RAASi post-transplant were compared to 70 lung transplant recipients not exposed to a RAASi and were followed for up to 5 years post-transplant. Results: The incidence of CLAD did not differ based on RAASi treatment (34.3% in RAASi vs 38.6%, P-value .668). This was confirmed with a multivariable Cox proportional hazards model with RAASi initiation as a time-varying covariate (RAASi hazard ratio of 1.01, P-value .986). Incidence of hyperkalemia and acute kidney injury were low in the RAASi group. Conclusions: This study demonstrated no association between post-transplant RAASi use and decreased risk of CLAD development. RAASi were also well tolerated in this patient population.

Use of dupilumab for atopic dermatitis in young transplant patients-A case series of 3 patients

Patients who undergo solid organ transplantation are at an increased risk of developing atopic dermatitis, potentially due to long-term use of calcineurin inhibitors which results in a shift towards the Th2 immune response. The effectiveness and safety of dupilumab for atopic dermatitis in posttransplant patients is not established. Previous reports of dupilumab use in posttransplant patients have been in adult patients. In this series, we report three young posttransplant patients treated successfully with dupilumab.

Use of Poly Lactic-co-glycolic Acid Nano and Micro Particles in the Delivery of Drugs Modulating Different Phases of Inflammation

Chronic inflammation contributes to the pathogenesis of many diseases, including apparently unrelated conditions such as metabolic disorders, cardiovascular diseases, neurodegenerative diseases, osteoporosis, and tumors, but the use of conventional anti-inflammatory drugs to treat these diseases is generally not very effective given their adverse effects. In addition, some alternative anti-inflammatory medications, such as many natural compounds, have scarce solubility and stability, which are associated with low bioavailability. Therefore, encapsulation within nanoparticles (NPs) may represent an effective strategy to enhance the pharmacological properties of these bioactive molecules, and poly lactic-co-glycolic acid (PLGA) NPs have been widely used because of their high biocompatibility and biodegradability and possibility to finely tune erosion time, hydrophilic/hydrophobic nature, and mechanical properties by acting on the polymer's composition and preparation technique. Many studies have been focused on the use of PLGA-NPs to deliver immunosuppressive treatments for autoimmune and allergic diseases or to elicit protective immune responses, such as in vaccination and cancer immunotherapy. By contrast, this review is focused on the use of PLGA NPs in preclinical in vivo models of other diseases in which a key role is played by chronic inflammation or unbalance between the protective and reparative phases of inflammation, with a particular focus on intestinal bowel disease; cardiovascular, neurodegenerative, osteoarticular, and ocular diseases; and wound healing.

An Enhanced Dissolving Cyclosporin-A Inhalable Powder Efficiently Reduces SARS-CoV-2 Infection In Vitro

This work illustrates the development of a dry inhalation powder of cyclosporine-A for the prevention of rejection after lung transplantation and for the treatment of COVID-19. The influence of excipients on the spray-dried powder's critical quality attributes was explored. The best-performing powder in terms of dissolution time and respirability was obtained starting from a concentration of ethanol of 45% (v/v) in the feedstock solution and 20% (w/w) of mannitol. This powder showed a faster dissolution profile (Weibull dissolution time of 59.5 min) than the poorly soluble raw material (169.0 min). The powder exhibited a fine particle fraction of 66.5% and an MMAD of 2.97 µm. The inhalable powder, when tested on A549 and THP-1, did not show cytotoxic effects up to a concentration of 10 µg/mL. Furthermore, the CsA inhalation powder showed efficiency in reducing IL-6 when tested on A549/THP-1 co-culture. A reduction in the replication of SARS-CoV-2 on Vero E6 cells was observed when the CsA powder was tested adopting the post-infection or simultaneous treatment. This formulation could represent a therapeutic strategy for the prevention of lung rejection, but is also a viable approach for the inhibition of SARS-CoV-2 replication and the COVID-19 pulmonary inflammatory process.

Allograft rejection following immune checkpoint inhibitors in solid organ transplant recipients: A safety analysis from a literature review and a pharmacovigilance system

AIM

This study aimed to systematically characterize transplant rejection after immune checkpoint inhibitors (ICIs) initiation in solid organ transplant recipients (SOTRs).

METHODS

Data were extracted from the US FDA Adverse Event Reporting System (FAERS) database and case reports in the literature. Disproportionality analysis including information component and reported odds ratio (ROR) was performed to access potential risk signals.

RESULTS

A total of 168 patients with transplant rejection after ICIs usage were identified in the FAERS database, and 89 cases were identified in the literature review. ICIs were significantly associated with transplant rejection (ROR₀₂₅ : 2.2). A strong risk signal was found for combination therapy with pembrolizumab and ipilimumab compared to monotherapy.

CONCLUSION

Immune checkpoint inhibitors were significantly associated with transplant rejection in SOTRs.

Identification of a potent dual-function inhibitor for hIMPDH isoforms by computer-aided drug discovery approaches

Inosine monophosphate dehydrogenase (IMPDH) is a key enzyme in de novo biosynthesis of purine nucleotides. Due to this important role, it is a great target to drug discovery for a wide range of activities, especially immunosuppressant in heart and kidney transplantation. Both human IMPDH isoforms are expressed in stimulated lymphocytes. In addition to the side effects of existing drugs, previous studies have mainly focused on the type II isoform. In this study, virtual screening and computer-aided approaches were employed to identify potential drugs with simultaneous inhibitory effects on both human IMPDH isoforms. After Re-docking, Double-step docking, and identification of virtual hits based on the PLANTS scoring function, drug-likeness and ADME-Tox assessments of the topmost ligands were performed. Following further evaluation, the best ligand was selected and, in complex with both isoforms, simulated in monomeric and tetrameric forms using molecular dynamics to evaluate its stability and binding pattern. The results showed a potential drug candidate [(S)-N-(3-hydroxy-1-(4-hydroxyphenyl) propyl)-2-(3-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl) acetamide] with a high inhibitory effect on the two human IMPDH isoforms. This drug-like inhibitor could potentially serve as an immunosuppressant to prevent transplant rejection response by inhibiting B- and T-lymphocyte proliferation. In addition, its effect can be evaluated in various therapeutic targets in which IMPDH is known as a therapeutic target, especially in Covid-19 patients.

The Inhibition of CD40/CD154 Costimulatory Signaling in the Prevention of Renal Transplant Rejection in Nonhuman Primates: A Systematic Review and Meta Analysis

The prevention of allograft transplant rejection by inhibition of the CD40/CD40L costimulatory pathway has been described in several species. We searched pubmed for studies reporting the prevention of kidney transplant rejection in nonhuman primates utilizing either anti CD40 or anti CD40L (CD154) treatment. Inclusion of data required treatment with anti CD40 or anti CD154 as monotherapy treatment arms, full text available, studies conducted in nonhuman primate species, the transplant was renal transplantation, sufficient duration of treatment to assess long term rejection, and the reporting of individual graft survival or survival duration. Eleven publications were included in the study. Rejection free survival was calculated using the Kaplan-Meier (KM) life test methods to estimate the survival functions. The 95% CI for the medians was also calculated. A log-rank test was used to test the equality of the survival curves between control and treatment arms (CD40 and CD154). The hazard ratio for CD154 compared to CD40 and 95% CI was calculated using a Cox proportional-hazards model including treatment as the covariate to assess the magnitude of the treatment effect. Both anti CD40 and anti CD154 treatments prevented acute and long term graft rejection. The median (95% CI) rejection free survival was 131 days (84,169 days) in the anti CD40 treated animals and 352 days (173,710 days) in the anti CD154 treated animals. Median survival in the untreated animals was 6 days. The inhibition of transplant rejection was more durable in the anti CD154 group compared to the anti CD40 group after cessation of treatment. The median (95% CI) rejection free survival after cessation of treatment was 60 days (21,80 days) in the anti CD40 treated animals and 230 days (84,552 days) in the anti CD154 treated animals.

US payer budget impact of a microarray assay with machine learning to evaluate kidney transplant rejection in for-cause biopsies

AIM

This study evaluates the economic impact to US commercial payers of MMDx-Kidney used in conjunction with histologic evaluation of for-cause kidney transplant biopsies.

MATERIALS AND METHODS

An Excel-based model was developed to assess the cost impact of histology plus MMDx-Kidney versus histology alone for the evaluation of potential rejection in kidney transplant patients who receive a for-cause biopsy. Different model time periods were assessed, ranging from 1 to 5 years post-biopsy. A targeted literature review was used to identify parameter estimates, validated by two external clinicians with expertise in managing kidney transplant rejection. A sensitivity analysis was conducted to evaluate the relative impact of key clinical and cost parameters. In particular, the model identified the magnitude of MMDx-Kidney's impact on graft failure from rejection that would be required for MMDx-Kidney to be cost-neutral.

RESULTS

By more accurately characterizing rejection, MMDx-Kidney is estimated to increase antirejection treatment costs by $1,126 per test. Nevertheless, a break-even analysis shows that the costs of MMDx-Kidney and anti-rejection medication, as well as the costs associated with an increase in the number of patients with functioning transplants, may be offset by reductions in costs associated with graft failure (i.e. costs of hospitalizations, dialysis, and repeat transplants) over 5 years, assuming MMDx-Kidney reduces annual graft failure from rejection by at least 5%. For the base case, with a 25% relative reduction in annual rate of graft failures from rejection, MMDx-Kidney increases overall costs incurred in the first year of the model but starts generating savings by the second year of the model.

CONCLUSIONS

Compared with histologic evaluation of for-cause kidney transplant biopsies alone, the use of MMDx-Kidney in conjunction with histologic evaluation improves the diagnoses of graft dysfunction and may have the potential to generate overall savings from reductions in rejection-related graft failure.

Intra-Organ Delivery of Nanotherapeutics for Organ Transplantation

Targeted delivery of therapeutics through the use of nanoparticles (NPs) has emerged as a promising method that increases their efficacy and reduces their side effects. NPs can be tailored to localize to selective tissues through conjugation to ligands that bind cell-specific receptors. Although the vast majority of nanodelivery platforms have focused on cancer therapy, efforts have begun to introduce nanotherapeutics to the fields of immunology as well as transplantation. In this review, we provide an overview from a clinician's perspective of current nanotherapeutic strategies to treat solid organ transplants with NPs during the time interval between organ harvest from the donor and placement into the recipient, an innovative technology that can provide major benefits to transplant patients. The use of ex vivo normothermic machine perfusion (NMP), which is associated with preserving the function of the organ following transplantation, also provides an ideal opportunity for a localized, sustained, and controlled delivery of nanotherapeutics to the organ during this critical time period. Here, we summarize previous endeavors to improve transplantation outcomes by treating the organ with NPs prior to placement in the recipient. Investigations in this burgeoning field of research are promising, but more extensive studies are needed to overcome the physiological challenges to achieving effective nanotherapeutic delivery to transplanted organs discussed in this review.

Diagnostic Accuracy of Cardiovascular Magnetic Resonance for Cardiac Transplant Rejection: A Meta-analysis

OBJECTIVES

The aim of this meta-analysis was to assess the diagnostic performance of various CMR imaging parameters for evaluating acute cardiac transplant rejection.

BACKGROUND

Endomyocardial biopsy is the current gold standard for detection of acute cardiac transplant rejection. Cardiac magnetic resonance (CMR) is uniquely capable of myocardial tissue characterization and may be useful as a noninvasive alternative for the diagnosis of graft rejection.

METHODS

PubMed and Web of Science were searched for relevant publications reporting on the use of CMR myocardial tissue characterization for detection of acute cardiac transplant rejection with endomyocardial biopsy as the reference standard. Pooled sensitivity, specificity, and hierarchical modeling-based summary receiver-operating characteristic curves were calculated.

RESULTS

Of 478 papers, 10 studies comprising 564 patients were included. The sensitivity and specificity for the detection of acute cardiac transplant rejection were 84.6 (95% CI: 65.6-94.0) and 70.1 (95% CI: 54.2-82.2) for T1, 86.5 (95% CI: 72.1-94.1) and 85.9 (95% CI: 65.2-94.6) for T2, 91.3 (95% CI: 63.9-98.4) and 67.6 (95% CI: 56.1-77.4) for extracellular volume fraction (ECV), and 50.1 (95% CI: 31.2-68.9) and 60.2 (95% CI: 36.7-79.7) for late gadolinium enhancement (LGE). The areas under the hierarchical modeling-based summary receiver-operating characteristic curve were 0.84 (95% CI: 0.81-0.87) for T1, 0.92 (95% CI: 0.89-94) for T2, 0.78 (95% CI: 0.74-0.81) for ECV, and 0.56 (95% CI: 0.51-0.60) for LGE. T2 values demonstrated the highest diagnostic accuracy, followed by native T1, ECV, and LGE (all P values < 0.001 for T1, ECV, and LGE vs T2).

CONCLUSIONS

T2 mapping demonstrated higher diagnostic accuracy than other CMR techniques. Native T1 and ECV provide high diagnostic use but lower diagnostic accuracy compared with T2, which was related primarily to lower specificity. LGE showed poor diagnostic performance for detection of rejection.

Complement Components in the Diagnosis and Treatment after Kidney Transplantation-Is There a Missing Link?

Currently, kidney transplantation is widely accepted as the renal replacement therapy allowing for the best quality of life and longest survival of patients developing end-stage renal disease. However, chronic transplant rejection, recurrence of previous kidney disease or newly acquired conditions, or immunosuppressive drug toxicity often lead to a deterioration of kidney allograft function over time. Complement components play an important role in the pathogenesis of kidney allograft impairment. Most studies on the role of complement in kidney graft function focus on humoral rejection; however, complement has also been associated with cell mediated rejection, post-transplant thrombotic microangiopathy, the recurrence of several glomerulopathies in the transplanted kidney, and transplant tolerance. Better understanding of the complement involvement in the transplanted kidney damage has led to the development of novel therapies that inhibit complement components and improve graft survival. The analysis of functional complotypes, based on the genotype of both graft recipient and donor, may become a valuable tool for assessing the risk of acute transplant rejection. The review summarizes current knowledge on the pathomechanisms of complement activation following kidney transplantation and the resulting diagnostic and therapeutic possibilities.

Immunologic Rejection of Transplanted Retinal Pigmented Epithelium: Mechanisms and Strategies for Prevention

Replacement of dysfunctional retinal pigmented epithelium (RPE) with grafts derived from stem cells has the potential to improve vision for patients with retinal disorders. In fact, the potential is such that a great number of groups are attempting to realize this therapy through individual strategies with a variety of stem cell products, hosts, immunomodulatory regimen, and techniques to assess the success of their design. Comparing the findings of different investigators is complicated by a number of factors. The immune response varies greatly between xenogeneic and allogeneic transplantation. A unique immunologic environment is created in the subretinal space, the target of RPE grafts. Both functional assessment and imaging techniques used to evaluate transplants are susceptible to erroneous conclusions. Lastly, the pharmacologic regimens used in RPE transplant trials are as numerous and variable as the trials themselves, making it difficult to determine useful results. This review will discuss the causes of these complicating factors, digest the strategies and results from clinical and preclinical studies, and suggest places for improvement in the design of future transplants and investigations.

A Noninvasive Urine Metabolome Panel as Potential Biomarkers for Diagnosis of T Cell-Mediated Renal Transplant Rejection

Acute T cell-mediated rejection (TCMR) is a major complication after renal transplantation. TCMR diagnosis is very challenging and currently depends on invasive renal biopsy and nonspecific markers such as serum creatinine. A noninvasive metabolomics panel could allow early diagnosis and improved accuracy and specificity. We report, in this study, on urine metabolome changes in renal transplant recipients diagnosed with TCMR, with a view to future metabolomics-based diagnostics in transplant medicine. We performed urine metabolomic analyses in three study groups: (1) 7 kidney transplant recipients with acute TCMR, (2) 15 kidney transplant recipients without rejection but with impaired kidney function, and (3) 6 kidney transplant recipients with stable renal function, using ¹H-nuclear magnetic resonance. Multivariate modeling of metabolites suggested a diagnostic panel where the diagnostic accuracy of each metabolite was calculated by receiver operating characteristic curve analysis. The impaired metabolic pathways associated with TCMR were identified by pathway analysis. In all, a panel of nine differential metabolites encompassing nicotinamide adenine dinucleotide, 1-methylnicotinamide, cholesterol sulfate, gamma-aminobutyric acid (GABA), nicotinic acid, nicotinamide adenine dinucleotide phosphate, proline, spermidine, and alpha-hydroxyhippuric acid were identified as novel potential metabolite biomarkers of TCMR. Proline, spermidine, and GABA had the highest area under the curve (>0.7) and were overrepresented in the TCMR group. Nicotinate and nicotinamide metabolism was the most important pathway in TCMR. These findings call for clinical validation in larger study samples and suggest that urinary metabolomics warrants future consideration as a noninvasive research tool for TCMR diagnostic innovation.

The growing dilemma of legalized cannabis and heart transplantation

This in-depth review discusses cannabis as it relates to heart transplantation and the growing dilemma of legalization around the world creating disparities in transplant candidacy. One will learn about two of the most common cannabinoids: Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD). These cannabinoids are metabolized by cytochrome P-450 and P glycoprotein, which are essential for the metabolism of drugs for transplantation, such as calcineurin inhibitors. Addiction, withdrawal, and cannabis use disorder will be reviewed as well as hyperemesis syndrome. Maintaining adequate immunosuppression will depend on a variety of factors, including drug-drug interactions, pharmacokinetics of cannabinoids and chronicity of cannabis usage. These drug interactions are further confounded by varying concentrations of cannabis products available at medical dispensaries. One will also learn about the outcomes of transplant recipients using cannabis such as graft failure and the risk of infections. Although more research is needed to establish transplant guidelines, the available data is concerning and fairness in organ distribution should not vary by transplant program or institution.

Artemisinin Attenuates Transplant Rejection by Inhibiting Multiple Lymphocytes and Prolongs Cardiac Allograft Survival

Immunological rejection is an important factor resulting in allograft dysfunction, and more valid therapeutic methods need to be explored to improve allograft outcomes. Many researches have indicated that artemisinin and its derivative exhibits immunosuppressive functions, apart from serving as a traditional anti-malarial drug. In this assay, we further explored the therapeutic effects of artemisinin for transplant rejection in a rat cardiac transplantation model. We found that it markedly attenuated allograft rejection and histological injury and significantly prolonged the survival of allograft. Upon further exploring the mechanism, we demonstrated that artemisinin not only attenuated T cell-mediated rejection (TCMR) by reducing effector T cell infiltration and inflammatory cytokine secretion and increasing regulatory T cell infiltration and immunoregulatory cytokine levels, but also attenuated antibody-mediated rejection (ABMR) through inhibition of B cells activation and antibody production. Furthermore, artemisinin also reduced macrophage infiltration in allografts, which was determined to be important for TCMR and ABMR. Moreover, we demonstrated that artemisinin significantly inhibited the function of pure T cells, B cells, and macrophages in vitro. All in all, this study provide evidence that artemisinin significantly attenuates TCMR and ABMR by targeting multiple effectors. Therefore, this agent might have potential for use in clinical settings to protect against transplant rejection.

The Immunobiogram, a Novel In Vitro Assay to Evaluate Treatment Resistance in Patients Receiving Immunosuppressive Therapy

Immunosuppressive drugs are widely used to treat several autoimmune disorders and prevent rejection after organ transplantation. However, intra-individual variations in the pharmacological response to immunosuppressive therapy critically influence its efficacy, often resulting in poor treatment responses and serious side effects. Effective diagnostic tools that help clinicians to tailor immunosuppressive therapy to the needs and immunological profile of the individual patient thus constitute a major unmet clinical need. In vitro assays that measure immune cell responses to immunosuppressive drugs constitute a promising approach to individualized immunosuppressive therapy. Here, we present the Immunobiogram, a functional pharmacodynamic immune cell-based assay for simultaneous quantitative measurement of a patient's immune response to a battery of immunosuppressive drugs. Peripheral blood mononuclear cells collected from patients are immunologically stimulated to induce activation and proliferation and embedded in a hydrogel mixture in which they are exposed to a concentration gradient of the immunosuppressants of interest. Analysis of samples from kidney transplant patients using this procedure revealed an association between the sensitivity of individual patients to the immunosuppressive regimen and their immunological risk of transplant rejection. Incorporation of the Immunobiogram assay into clinical settings could greatly facilitate personalized optimization and monitoring of immunosuppressive therapy, and study of the mechanisms underlying resistance to immunosuppressants.

ITK inhibition promotes long-term survival of cardiac allografts by regulating T cell PLCγ phosphorylation

BACKGROUND

T cells express interleukin-2 inducible T-cell kinase (ITK), which is an essential modulator of T-cell signaling and function. However, the role of ITK in solid organ transplantation has not been investigated to date. Here, we studied the function of ITK in a murine cardiac transplantation model.

METHOD

Murine heart transplantation was performed using BALB/C mice as donors and C57BL/6 mice as recipients. Subsequent intraperitoneal injections of an ITK-specific inhibitor (BMS-509744) were performed to assess the effects of the kinase following cardiac transplantation. Additionally, naive T cells were isolated to investigate the inhibitor's potential effects in the alloimmune responses.

RESULTS

ITK inhibition was found to promote long-term cardiac allograft survival compared with the control group of 36.0 ± 3.8 days vs. 7.0 ± 0.7 days, respectively (P < 0.01). While the Th1/Th17 percentages showed a decrease in prevalence (P < 0.001), the CD4⁺CD25⁺Foxp3⁺ percentages were not markedly affected. In vitro treatment of CD4⁺ T cells with the ITK inhibitor downregulated the proliferation, possibly by regulating the phosphorylation of PLCγ.

CONCLUSION

ITK inhibition resulted in lower Th1/Th17 responses after cardiac transplantation and markedly prolonged the mean survival time of the cardiac allografts. Thus, ITK inhibition might be a promising therapeutic target to alleviate alloimmune responses in the cardiac transplantation.

Conversion to belatacept maintenance immunosuppression in HIV-positive kidney transplant recipients

There are only scattered case reports documenting belatacept use in HIV + kidney transplant recipients. We performed a retrospective review to describe short-term outcomes following conversion to belatacept in a cohort of HIV + patients. Patients were included if they were converted to belatacept between May 2015 and May 2019, had an HIV- donor, and received ≥4 doses of belatacept. All patients were treated with non-depleting induction and triple maintenance immunosuppression. Allograft and HIV-related outcomes were collected from the date of belatacept infusion until May 2020. Ten HIV + kidney transplant recipients were identified, who were converted to belatacept a median of 364 days post-transplant. At last follow-up (median 3.3 years), 8 patients remained on belatacept therapy, and all patients were alive with functioning allografts. Mean estimated glomerular filtration rates (eGFR) improved from 31.6 mL/min at baseline to 42.8 mL/min at 1 year (P = .03). Two patients developed acute rejection, with one necessitating conversion back to tacrolimus. All patients maintained undetectable HIV-1 viral loads at last follow-up. One patient each developed pneumocystis pneumonia and Kaposi sarcoma following conversion, which were responsive to standard medical therapy. In our cohort of stable HIV + kidney transplant recipients, conversion to belatacept was associated with excellent early patient and allograft survival and improved eGFR at 1 year.

The Effect of Proton Pump Inhibitor Use on Renal Function in Kidney Transplanted Patients

Recently, proton pump inhibitor (PPI) intake has been linked to acute kidney injury and chronic kidney disease. The objective of this study was to assess the effect of PPIs on renal function and rejection rate in kidney transplant patients. We performed a single center, retrospective analysis of 455 patients who received a kidney transplant between May 2010 and July 2015. Median follow-up time was 3.3 years. PPI prescription was assessed in half-year intervals. Primary outcome parameters were the estimated glomerular filtration rate (eGFR), change in the eGFR, and >30% and >50% eGFR decline for different time periods (up to four years post-transplantation). Our secondary outcome parameter was occurrence of biopsy proven acute rejection (BPAR) in the first two years after transplantation. Except for >30% eGFR decline from half a year to two years post-transplantation (p = 0.044) and change in the eGFR, >30% and >50% eGFR decline showed no association with PPI intake in our patient cohort (p > 0.05). Similarly, by analyzing 158 rejection episodes, BPAR showed no correspondence with mean daily PPI intake. We conclude that prolonged PPI intake has no relevant adverse effect on kidney transplant function or rejection rates. Polypharmacy, however, remains a problem in renal transplant recipients and it is thus advisable to question the necessity of PPI prescriptions when clear indications are missing.

Therapeutic Application of Mesenchymal Stem Cells Derived Extracellular Vesicles for Immunomodulation

The immunosuppressive potential of mesenchymal stem cells has been extensively investigated in many studies in vivo and in vitro. In recent years, a variety preclinical and clinical studies have demonstrated that mesenchymal stem cells ameliorate immune-mediated disorders, including autoimmune diseases. However, to date mesenchymal stem cells have not become a widely used therapeutic agent due to safety challenges, high cost and difficulties in providing long term production. A key mechanism underpinning the immunomodulatory effect of MSCs is the production of paracrine factors including growth factors, cytokines, chemokines, and extracellular vesicles (EVs). MSCs derived EVs have become an attractive therapeutic agent for immunomodulation and treatment of immune-mediated disorders. In addition to many preclinical studies of MSCs derived EVs, their beneficial effects have been observed in patients with both acute graft-vs.-host disease and chronic kidney disease. In this review, we discuss the current findings in the field of MSCs derived EVs-based therapies in immune-mediated disorders and approaches to scale EV production for clinical use.

Quantitative myocardial tissue characterization by cardiac magnetic resonance in heart transplant patients with suspected cardiac rejection

Distinct histopathologic changes occur in acute cellular rejection (ACR), antibody-mediated rejection (AMR), and biopsy-negative rejection (BNR). Cardiovascular magnetic resonance (CMR)-based myocardial tissue characterization can be used to quantify these changes. We assessed T1, T2, and extracellular volume fraction (ECV) by CMR in patients with subtypes of rejection. T1, T2, and ECV were quantified at the mid-ventricular level and compared between patients with and without rejection. The association between quantitative tissue characteristics and the combined outcome of death, retransplantation, heart failure hospitalization, or myocardial infarction was evaluated with a Cox-proportional hazards model. In 46 patients, mean age 53.3 ± 13.7 years, 71.7% male, at a median of 7.4 years from transplant, average myocardial T1 was increased in BNR compared with no rejection (1057 vs 1012 msec, P = .006). Average myocardial T2 was elevated in all types of rejection, P < .05. In a cox-proportional hazards model, higher T2 values were associated with an increase in the combined clinical outcome (adjusted HR 1.21, 95% CI 1.06-1.37, P = .004) after adjusting for left ventricular mass index. Myocardial tissue characteristics are abnormal in all subtypes of rejection, and abnormal T2 quantified by CMR provides additional prognostic value.

Heart or lung transplant outcomes in HIV-infected recipients

BACKGROUND

Limited published data exist on outcomes related to heart and/or lung transplantation in human immunodeficiency virus (HIV)-infected individuals.

METHODS

We conducted a multicenter retrospective study of heart and lung transplantation in HIV-infected patients and describe key transplant- and HIV-related outcomes.

RESULTS

We identified 29 HIV-infected thoracic transplant recipients (21 heart, 7 lung, and 1 heart and/or lung) across 14 transplant centers from 2000 through 2016. Compared with an International Society for Heart and Lung Transplantation registry cohort, we demonstrated similar 1-, 3-, and 5-year patient and allograft survivals for each organ type with a median follow up of 1,064 (range, 184-3,745) days for heart and 1,540 (range, 116-3,206) days for lung recipients. At 1 year, significant rejection rates were high (62%) for heart transplant recipients (HTRs). Risk factors for rejection were inconclusive, likely because of small numbers, but may be related to cautious early immunosuppression and infrequent use of induction therapy. Pulmonary bacterial infections were high (86%) for lung transplant recipients (LTRs). Median CD4 counts changed from baseline to 1 year from 399 to 411 cells/µl for HTRs and 638 to 280 cells/µl for LTRs. Acquired immunodeficiency syndrome-related events, including infections and malignancies, were rare. Rates of severe renal dysfunction suggest a need to modify nephrotoxic anti-retrovirals and/or immunosuppressants.

CONCLUSIONS

HIV-infected HTRs and LTRs have similar survival rates to their HIV-uninfected counterparts. Although optimal immunosuppression is not defined, it should be at least as aggressive as that for HIV-uninfected recipients. Such data may help pave the way for the use of hearts and lungs from HIV-infected donors in HIV-infected recipients through HIV Organ Policy Equity Act protocols.

Critical Care after Lung Transplantation

Since the first successful lung transplantation in 1983, there have been many advances in the field. Nevertheless, the latest data from the International Society for Heart and Lung Transplantation revealed that the risk of death from transplantation is 9%. Various aspects of postoperative management, including mechanical ventilation, could affect intensive care unit stay, hospital stay, and immediate postoperative morbidity and mortality. Complications such as reperfusion injury, graft rejection, infection, and dehiscence of anastomosis increase fatal adverse side effects immediately after surgery. In this article, we review the possible immediate complications after lung transplantation and summarize current knowledge on prevention and treatment.

Molecular Assessment of C4d-Positive Renal Transplant Biopsies Without Evidence of Rejection

Introduction

Immunohistochemical staining for C4d in peritubular capillaries has been part of antibody-mediated rejection (AbMR) definition in the Banff Classification for Allograft Pathology since 2003. However, it has limited sensitivity and specificity, therefore the clinical significance of C4d-positive biopsies without evidence of rejection (C4d+ WER) is unknown. We investigated the transcript levels of genes associated with AbMR in C4d+ WER biopsies from both ABO-compatible and incompatible renal transplant patients.

Methods

RNA was extracted from formalin-fixed paraffin-embedded renal transplant biopsies (n = 125) and gene expression analysis of 35 AbMR-associated transcripts carried out using the NanoString nCounter system.

Results

AbMR-associated transcripts were significantly increased in samples with AbMR or suspicious AbMR. A subgroup of 17 of 35 transcripts that best distinguished AbMR from C4d-negative biopsies without evidence of rejection was used to study C4d+ WER samples. There was no differential expression between C4d-negative and C4d+ WER from both ABO-incompatible and -compatible transplants. The geometric mean of 17 differentially expressed genes was used to assign the C4d+ WER biopsies a high- or low-AbMR transcript score. Follow-up biopsies showed AbMR within 1 year of initial biopsy in 5 of 7 high-AbMR transcript patients but only 2 of 46 low-AbMR transcript patients. In multivariate logistic regression analysis, elevated transcript levels in a C4d+ WER biopsy were associated with increased odds for biopsy-proven AbMR on follow-up (P = 0.032, odds ratio 16.318), whereas factors including donor-specific antibody (DSA) status and time since transplantation were not.

Conclusion

Gene expression analysis in C4d+ WER samples has the potential to identify patients at higher risk of developing AbMR.

Recent advances in heart transplantation

Despite advances in medical and electrical therapies for heart failure, morbidity and mortality remain high and patients often progress to end-stage heart failure. Over the last five decades, heart transplantation is considered a standard therapy for select patients with end-stage heart failure. However, while heart transplantation has become a treatment of choice for end-stage heart failure, challenges still exist for improvement in the short- and long-term outcomes. While there is an increase in the number of patients with end-stage heart failure, the number of donor organs remains a major limiting factor. Heart transplantation candidates in the current era are also more complex: older, antigen-sensitized, and on mechanical circulatory support at the time of listing and transplant. Such potential heart transplant recipients have an increased chance of problems, including antibody-mediated rejection and primary graft dysfunction. Recent advances could address the current challenges and include: 1) attempts to expand the pool of donor hearts; 2) changes in heart transplantation allocation policy allowing for more equitable organ distribution; and 3) advances in the management of antibody sensitization. Developments in these areas could result in improved survival and quality of life for heart transplantation recipients.

American council on ECP (ACE): Why now?

Stimulated by the scientific progress in deciphering the principal elements contributing to the clinical efficacy of extracorporeal photochemotherapy (ECP), the American Council on ECP (ACE) was formed, under the auspices of the American Society for Apheresis (ASFA), to develop a field-guiding Consensus Report. ACE is composed of thirty nationally recognized ECP experts, clinically spanning cancer, transplantation, and autoimmunity and scientifically bridging immunology, bioengineering, and hematology. The two-day meeting took place in Manhattan, April 13-14, 2017, and unanimous consensus on nine pivotal points is herein reported. (1) ECP's clinical evolution must now enter a scientifically driven phase. (2) ECP is currently a bidirectional therapy, both immunizing and tolerizing simultaneously, via a single one-size-fits-all inflexible medical device. (3) To preclude inadvertent tolerization in the cancer setting, or immunization in the transplant rejection setting, polarization of ECP to either immunization or tolerization mode to match the clinical need is now possible and necessary. (4) Cutaneous T cell lymphoma (CTCL) is a genetically driven cancer, whose response to ECP is due to enhanced anti-cancer immunity. (5) ECP is a dendritic antigen-presenting cell (DC) based therapy. (6) ECP's efficacy can now be tested in a broad array of cancers. (7) ECP's capacity to tolerize to allotransplants via processing of donor leukocytes merits expedited human investigation. (8) UVA-8-MOP-impacted ECP-induced DC are potent antigen-specific tolerizing agents, while UVA-8-MOP(8-Methoxypsoralen)-spared ECP-induced DC are potent antigen-specific immunizing agents. (9) Six pilot clinical trial areas (CTCL, graft-vs.-host disease, ovarian carcinoma, anti-graft cytotoxic antibodies, pemphigus vulgaris, and haplotype mismatched stem cell transplants) are advised. ACE will be an ongoing advisory group for the field, with the goal of overseeing coordinated clinical and fundamental research efforts.

Eponychial lesions following bilateral upper extremity vascular composite allotransplantation: a case report

Vascularized composite allotransplantation represents a useful addition to reconstructive options available to the plastic surgeon. Though the procedure provides beneficial functional outcomes, there remain complications, often associated with the immunosuppression necessary to maintain an allograft. We report a case of eponychial fold lesions following successful bilateral upper extremity allotransplantation.

Diagnostic accuracy of contrast-enhanced ultrasound (CEUS) in monitoring vascular complications in patients after liver transplantation - diagnostic performance compared with histopathological results

PURPOSE

To analyse the diagnostic performance of contrast-enhanced ultrasound (CEUS) in patients with vascular complications and transplant rejection compared to histopathological results.

MATERIALS AND METHODS

Our study consisted of 45 retrospectively analysed patients that underwent liver transplantations between January 1993 and December 2015 and developed post-transplant vascular complications with transplant rejection. CEUS examinations took place between September 2006 and December 2015. CEUS findings were correlated with histopathological results.

RESULTS

CEUS showed a sensitivity of 61.5%, a specificity of 100.0%, a positive predictive value (PPV) of 100.0% and a negative predictive value (NPV) of 86,5% in the detection of vascular complications with post-transplant rejection. 5 examinations were reported as normal whereas the histopathological result showed a transplant rejection (false-negative).

CONCLUSION

CEUS might be a useful additional non-invasive technique for the assessment of vascular complications with post-transplant rejection in patients after liver transplantation.

Lung Transplant in Patients with Scleroderma Compared with Pulmonary Fibrosis. Short- and Long-Term Outcomes

RATIONALE

Patients with advanced lung disease due to systemic sclerosis have long been considered suboptimal and often unacceptable candidates for lung transplant.

OBJECTIVES

To examine post-lung transplant survival of patients with systemic sclerosis compared with patients with pulmonary fibrosis and to identify risk factors for 1-year mortality.

METHODS

In a retrospective cohort study, we compared post-lung transplant outcomes of 72 patients with scleroderma with those of 311 patients with pulmonary fibrosis between June 2005 and September 2013 at our institution. Actuarial survival estimates were calculated using Kaplan-Meier curves. In Cox regression models, we determined risk factors for post-transplant mortality, controlling for whether patients had scleroderma or pulmonary fibrosis.

MEASUREMENTS AND MAIN RESULTS

Post-transplant survival did not differ significantly between scleroderma and pulmonary fibrosis at year 1 (81% scleroderma vs. 79% pulmonary fibrosis; P = 0.743), at year 5 conditional on 1-year survival (66% vs. 58%; P = 0.249), or overall (P = 0.385). In multivariate analysis, body mass index greater than or equal to 35 kg/m(2) predicted poor 1-year survival in pulmonary fibrosis (hazard ratio, 2.76; P = 0.003). Acute cellular rejection-free survival did not differ significantly between the scleroderma and pulmonary fibrosis cohorts. Patients with scleroderma had significantly better bronchiolitis obliterans syndrome stage 1 or higher-free survival than did patients with pulmonary fibrosis.

CONCLUSIONS

Our findings that 1- and 5-year survival rates of patients with scleroderma were similar to those of patients with pulmonary fibrosis indicate that lung transplant is a reasonable treatment option in selected patients with scleroderma.

Proton Pump Inhibitors: More Indigestion than Relief?

Proton pump inhibitors (PPIs) are widely prescribed to treat a number of gastrointestinal (GI) disorders due to excessive acid production. While effective and safe, adverse renal effects have been increasingly described in epidemiological literature. The most well-documented adverse renal outcome is acute interstitial nephritis; however, association with overall acute kidney injury has also been recently reported. Recently, two observational studies have linked PPI use with chronic kidney disease. Finally, hypomagnesemia is another reported complication and is thought to be resulting from GI loss of magnesium. This study will critically review literature on the effect of PPIs on the kidney.

Sudden death in a pediatric heart transplant recipient with peripheral eosinophilia and eosinophilic myocardial infiltrates

Eosinophilia has been rarely reported in pediatric heart transplant recipients and has been suggested to play a role in graft rejection. We report a case of a young female patient with peripheral blood eosinophilia who died suddenly 2 years following ABO-incompatible heart transplantation. She was found at autopsy to have myocardial infiltration of not only T-lymphocytes and macrophages expected in acute cellular rejection but also of eosinophils, B-lymphocytes, and plasma cells indicating myocarditis.

Comparative Analysis of Immune Checkpoint Molecules and Their Potential Role in the Transmissible Tasmanian Devil Facial Tumor Disease

Immune checkpoint molecules function as a system of checks and balances that enhance or inhibit immune responses to infectious agents, foreign tissues, and cancerous cells. Immunotherapies that target immune checkpoint molecules, particularly the inhibitory molecules programmed cell death 1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), have revolutionized human oncology in recent years, yet little is known about these key immune signaling molecules in species other than primates and rodents. The Tasmanian devil facial tumor disease is caused by transmissible cancers that have resulted in a massive decline in the wild Tasmanian devil population. We have recently demonstrated that the inhibitory checkpoint molecule PD-L1 is upregulated on Tasmanian devil (Sarcophilus harrisii) facial tumor cells in response to the interferon-gamma cytokine. As this could play a role in immune evasion by tumor cells, we performed a thorough comparative analysis of checkpoint molecule protein sequences among Tasmanian devils and eight other species. We report that many of the key signaling motifs and ligand-binding sites in the checkpoint molecules are highly conserved across the estimated 162 million years of evolution since the last common ancestor of placental and non-placental mammals. Specifically, we discovered that the CTLA-4 (MYPPPY) ligand-binding motif and the CTLA-4 (GVYVKM) inhibitory domain are completely conserved across all nine species used in our comparative analysis, suggesting that the function of CTLA-4 is likely conserved in these species. We also found that cysteine residues for intra- and intermolecular disulfide bonds were also highly conserved. For instance, all 20 cysteine residues involved in disulfide bonds in the human 4-1BB molecule were also present in devil 4-1BB. Although many key sequences were conserved, we have also identified immunoreceptor tyrosine-based inhibitory motifs (ITIMs) and immunoreceptor tyrosine-based switch motifs (ITSMs) in genes and protein domains that have not been previously reported in any species. This checkpoint molecule analysis and review of salient features for each of the molecules presented here can serve as road map for the development of a Tasmanian devil facial tumor disease immunotherapy. Finally, the strategies can be used as a guide for veterinarians, ecologists, and other researchers willing to venture into the nascent field of wild immunology.

Role of Memory T Cells in Allograft Rejection and Tolerance

Memory T cells are characterized by their low activation threshold, robust effector functions, and resistance to conventional immunosuppression and costimulation blockade. Unlike their naïve counterparts, memory T cells reside in and recirculate through peripheral non-lymphoid tissues. Alloreactive memory T cells are subdivided into different categories based on their origins, phenotypes, and functions. Recipients whose immune systems have been directly exposed to allogeneic major histocompatibility complex (MHC) molecules display high affinity alloreactive memory T cells. In the absence of any prior exposure to allogeneic MHC molecules, endogenous alloreactive memory T cells are regularly generated through microbial infections (heterologous immunity). Regardless of their origin, alloreactive memory T cells represent an essential element of the allograft rejection process and a major barrier to tolerance induction in clinical transplantation. This article describes the different subsets of alloreactive memory T cells involved in transplant rejection and examine their generation, functional properties, and mechanisms of action. In addition, we discuss strategies developed to target deleterious allospecific memory T cells in experimental animal models and clinical settings.

A Paradigm Shift on the Question of B Cells in Transplantation? Recent Insights on Regulating the Alloresponse

B lymphocytes contribute to acute and chronic allograft rejection through their production of donor-specific antibodies (DSAs). In addition, B cells present allopeptides bound to self-MHC class II molecules and provide costimulation signals to T cells, which are essential to their activation and differentiation into memory T cells. On the other hand, both in laboratory rodents and patients, the concept of effector T cell regulation by B cells is gaining traction in the field of transplantation. Specifically, clinical trials using anti-CD20 monoclonal antibodies to deplete B cells and reverse DSA had a deleterious effect on rates of acute cellular rejection; a peculiar finding that calls into question a central paradigm in transplantation. Additional work in humans has characterized IL-10-producing B cells (IgM memory and transitional B cells), which suppress the proliferation and inflammatory cytokine productions of effector T cells in vitro. Understanding the mechanisms of regulating the alloresponse is critical if we are to achieve operational tolerance across transplantation. This review will focus on recent evidence in murine and human transplantation with respect to non-traditional roles for B cells in determining clinical outcomes.

Use of polyclonal/monoclonal antibody therapies in transplantation

INTRODUCTION

For over thirty years, antibody (mAb)-based therapies have been a standard component of transplant immunosuppression, and yet much remains to be learned in order for us to truly harness their therapeutic capabilities. Current mAbs used in transplant directly target and destroy graft-destructive immune cells, interrupt cytokine and costimulation-dependent T and B cell activation, and prevent down-stream complement activation. Areas covered: This review summarizes our current approaches to using antibody-based therapies to prevent and treat allograft rejection. It also provides examples of promising novel mAb therapies, and discusses the potential for future mAb development in transplantation. Expert opinion: The broad capability of antibodies, in parallel with our growing ability to synthetically modulate them, offers exciting opportunities to develop better biologic therapeutics. In order to do so, we must further our understanding about the basic biology underlying allograft rejection, and gain better appreciation of how characteristics of therapeutic antibodies affect their efficacy.

Inosine-5'-monophosphate dehydrogenase (IMPDH) inhibitors: a patent and scientific literature review (2002-2016)

INTRODUCTION

Inosine-5'-monophosphate dehydrogenase (IMPDH) is an enzyme involved in the de novo biosynthesis of guanine nucleotides. To date human IMPDH inhibitors have been approved for prevention of organ transplant rejection and as anti-viral agents. More recently, the use of IMPDH inhibitors for other indications including cancer and pathogenic microorganisms has been pursued. Areas covered: IMPDH inhibitors disclosed primarily in the patent and scientific literature from 2002 to the present are discussed. Several interesting chemotypes that have not been pursued by patent protection are also highlighted. Expert opinion: Progress has been made in the development of IMPDH inhibitors, particularly compounds that are structurally distinct from mycophenolic acid and nucleoside-based inhibitors. However, clinical progression has been hampered primarily by a limited understanding of the enzyme's role in disease pathophysiology. Finally, most of the IMPDH inhibitors developed over the past fourteen years fall within a relatively narrow set of chemotypes. This provides opportunities for expanding IMPDH inhibitor chemical space to further evaluate this class of molecular targets.

The Impact of HLA Class I-Specific Killer Cell Immunoglobulin-Like Receptors on Antibody-Dependent Natural Killer Cell-Mediated Cytotoxicity and Organ Allograft Rejection

Natural killer (NK) cells of the innate immune system are cytotoxic lymphocytes that play an important roles following transplantation of solid organs and hematopoietic stem cells. Recognition of self-human leukocyte antigen (HLA) class I molecules by inhibitory killer cell immunoglobulin-like receptors (KIRs) is involved in the calibration of NK cell effector capacities during the developmental stage, allowing the subsequent recognition and elimination of target cells with decreased expression of self-HLA class I (due to virus infection or tumor transformation) or HLA class I disparities (in the setting of allogeneic transplantation). NK cells expressing an inhibitory KIR-binding self-HLA can be activated when confronted with allografts lacking a ligand for the inhibitory receptor. Following the response of the adaptive immune system, NK cells can further destroy allograft endothelium by antibody-dependent cell-mediated cytotoxicity (ADCC), triggered through cross-linking of the CD16 Fc receptor by donor-specific antibodies bound to allograft. Upon recognizing allogeneic target cells, NK cells also secrete cytokines and chemokines that drive maturation of dendritic cells to promote cellular and humoral adaptive immune responses against the allograft. The cumulative activating and inhibitory signals generated by ligation of the receptors regulates mature NK cell killing of target cells and their production of cytokines and chemokines. This review summarizes the role of NK cells in allograft rejection and proposes mechanistic concepts that indicate a prominent role for KIR-HLA interactions in facilitating NK cells for Fc receptor-mediated ADCC effector function involved in antibody-mediated rejection of solid organ transplants.

Outcomes of kidney transplantation in Alport syndrome compared with other forms of renal disease

Introduction: Alport syndrome is an inherited renal disease characterized by hematuria, renal failure, hearing loss and a lamellated glomerular basement membrane. Patients with Alport syndrome who undergo renal transplantation have been shown to have patient and graft survival rates similar to or better than those of patients with other renal diseases.

Methods: In this national case series, based in Beaumont Hospital Dublin, we studied the cohort of patients who underwent renal transplantation over the past 33 years, recorded prospectively in the Irish Renal Transplant Registry, and categorized them according to the presence or absence of Alport syndrome. The main outcomes assessed were patient and renal allograft survival.

Results: Fifty-one patients diagnosed with Alport syndrome in Beaumont Hospital received 62 transplants between 1982 and 2014. The comparison group of non-Alport patients comprised 3430 patients for 3865 transplants. Twenty-year Alport patient survival rate was 70.2%, compared to 44.8% for patients with other renal diseases (p = .01). Factors associated with patient survival included younger age at transplantation as well as differences in recipient sex, donor age, cold ischemia time, and episodes of acute rejection. Twenty-year graft survival was 46.8% for patients with Alport syndrome compared to 30.2% for those with non-Alport disease (p = .11).

Conclusions: Adjusting for baseline differences between the groups, patients with end-stage kidney disease (ESKD) due to Alport syndrome have similar patient and graft survival to those with other causes of ESKD. This indicates that early diagnosis and management can lead to favorable outcomes for this patient cohort.

Lymphoid-Like Structures with Distinct B Cell Areas in Kidney Allografts are not Predictive for Graft Rejection. A Non-human Primate Study

Kidney allograft biopsies were analyzed for the presence of B cell clusters/aggregates using CD20 staining. Few B cells were found in the diffuse interstitial infiltrates, but clusters of B cells were found in nodular infiltrates. These nodular infiltrates were smaller shortly after transplantation, and their size increased over time. At the time of clinical rejection, the nodules often presented as tertiary lymphoid structures (TLS) with lymphoid-like follicles. The presence of small B cell clusters during the first 2 months after transplantation was not associated with early rejection. Even in animals that did not reject their allograft, TLS-like structures were present and could disappear over time. Although TLS were more often found in samples with interstitial fibrosis and tubular atrophy (IFTA), TLS were also present in samples without IFTA. The presence and density of clusters resembling tertiary lymphoid structures most likely reflect an ongoing immune response inside the graft and do not necessarily signify a poor graft outcome or IFTA.

Senescence in chronic allograft nephropathy

Despite increasing numbers of patients on dialysis, the numbers of renal transplants performed yearly have remained relatively static. During the last 50 years, there have been many advances in the pharmacology of prevention of organ rejection. However, most patients will suffer from a slow but steady decline in renal function leading to graft loss. The most common cause of long-term graft loss is chronic allograft nephropathy (CAN). Therefore, elucidating and understanding the mechanisms involved in CAN is crucial for achieving better posttransplant outcomes. It is thought that the development of epithelial to mesenchymal transition (EMT) in proximal tubules is one of the first steps towards CAN, and has been shown to be a result of cellular senescence. Cells undergoing senescence acquire a senescence associated secretory phenotype (SASP) leading to the production of interleukin-1 alpha (IL-1α), which has been implicated in several degenerative and inflammatory processes including renal disease. A central mediator in SASP activation is the production of reactive oxygen species (ROS), which are produced in response to numerous physiological and pathological stimuli. This review explores the connection between SASP and the development of EMT/CAN in an effort to suggest future directions for research leading to improved long-term graft outcomes.

High-dose immunosuppressant alters the immunological status of New Zealand white rabbits following skin transplantation

The aim of this study was to investigate the effect of an immunosuppressant on the immunological status of New Zealand white rabbits after skin grafting, and to evaluate a method for monitoring the immunological status of subjects with skin transplants. The rabbits were randomly divided into allograft rejection, autograft tolerance, nontransplant, allograft low-dose immunosuppressant and allograft high-dose immunosuppressant groups. The rabbits in the low- and high-dose immunosuppressant groups were treated with cyclosporine A intravenously 8 h prior to skin transplantation and once daily following transplantation at doses of 2 and 25 mg/kg, respectively. At 12 days after skin transplantation, the spleens of donor (female) rabbits and recipient (male) rabbits were harvested for the preparation of single-cell suspensions. The splenocytes from recipient and donor rabbits were labeled with 0.3 or 6 µM carboxy fluorescein diacetate succinimidyl ester, respectively, and a mixed cell suspension was prepared. The final preparation was intravenously injected into recipient New Zealand white rabbits. The ratio of the two fluorescently labeled cell populations in the peripheral blood was measured using flow cytometry at 1, 2, 4 and 8 h after the injection, and the cell death rate was calculated. Histological analysis was also performed on samples collected at the time of splenectomy. The cell death rates of the allograft rejection and low-dose immunosuppressant groups reached their highest levels 8 h after the injection of spleen cell suspension. Allogeneic spleen cells from donor male rabbits were almost completely removed within 8 h of injection. The cell death rate increased slowly in the nontransplant, autograft and high-dose immunosuppressant groups without specificity. This study provides a specific method for the in vivo monitoring of the immunological status of patients after skin grafting. This method can quickly and accurately detect the immunological status of recipients following the injection of a mixed splenocyte suspension, thereby indicating the strength of immune rejection by the immune systems of the recipients.