Immunosuppressive drugs for kidney transplantation

Prolonged-Release Once-Daily Formulation of Tacrolimus Versus Standard-of-Care Tacrolimus in de novo Kidney Transplant Patients Across Europe

Background: Tacrolimus is the calcineurin inhibitor of choice for preventing acute rejection episodes in kidney transplant patients. However, tacrolimus has a narrow therapeutic range that requires regular monitoring of blood concentrations to minimize toxicity. A new once-daily tacrolimus formulation, LCP-tacrolimus (LCPT), has been developed, which uses MeltDose™ drug-delivery technology to control drug release and enhance overall bioavailability. Our study compared dosing of LCPT with current standard-of-care tacrolimus [immediate-release tacrolimus (IR-Tac) or prolonged-release tacrolimus (PR-Tac)] during the 6 months following de novo kidney transplantation. Comparisons of graft function, clinical outcomes, safety, and tolerability for LCPT versus IR-Tac/PR-Tac were also performed.

Methods: Standard immunological risk patients with end-stage renal disease who had received a de novo kidney transplant were randomized (1:1) to LCPT (N = 200) or IR-Tac/PR-Tac (N = 201).

Results: Least squares (LS) mean tacrolimus total daily dose from Week 3 to Month 6 was significantly lower for LCPT than for IR-Tac/PR-Tac. Although LS mean tacrolimus trough levels were significantly higher for LCPT than IR-Tac/PR-Tac, tacrolimus trough levels remained within the standard reference range for most patients. There were no differences between the groups in treatment failure measures or safety profile.

Conclusion: LCPT can achieve similar clinical outcomes to other tacrolimus formulations, with a lower daily dose.

Clinical Trial Registration:https://clinicaltrials.gov/, identifier NCT02432833.

The Expansion of Myeloid-Derived Suppressor Cells Correlates With the Severity of Pneumonia in Kidney Transplant Patients

Background

Pneumonia is one of the most frequent but serious infectious complications post kidney transplantation. Severe pneumonia induces sustained immunosuppression, but few parameters concerning immune status are used to assess the severity of pneumonia. Myeloid-derived suppressor cells (MDSCs) are induced under infection and have the strong immunosuppressive capacity, but the correlation between MDSCs and pneumonia in kidney transplant recipients (KTRs) is unknown.

Methods

Peripheral blood MDSCs were longitudinally detected in 58 KTRs diagnosed with pneumonia using flow cytometry and in 29 stable KTRs as a control. The effectors of MDSCs were detected in the plasma. Spearman's rank correlation analysis was performed to determine the correlation between MDSCs and the severity of pneumonia as well as lymphopenia.

Results

The frequency of MDSCs and effectors, including arginase-1, S100A8/A9, and S100A12, were significantly increased in the pneumonia group compared with the stable group. CD11b⁺CD14⁺HLA-DR^low/−CD15⁻ monocytic-MDSCs (M-MDSCs) were higher in the pneumonia group but showed no significant difference between the severe and non-severe pneumonia subgroups. CD11b⁺CD14⁻CD15⁺ low-density granulocytic-MDSCs (G-MDSCs) were specifically increased in the severe pneumonia subgroup and correlated with the severity of pneumonia as well as lymphopenia. During the study period of 2 weeks, the frequencies of MDSCs and G-MDSCs were persistently increased in the severe pneumonia subgroup.

Conclusions

MDSCs and G-MDSCs were persistently increased in KTRs with pneumonia. G-MDSCs were correlated with the severity of pneumonia and could thus be an indicator concerning immune status for assessing pneumonia severity.

T-cell Exhaustion in Organ Transplantation

Exhaustion of T cells occurs in response to long-term exposure to self and foreign antigens. It limits T cell capacity to proliferate and produce cytokines, leading to an impaired ability to clear chronic infections or eradicate tumors. T-cell exhaustion is associated with a specific transcriptional, epigenetic, and metabolic program and characteristic cell surface markers' expression. Recent studies have begun to elucidate the role of T-cell exhaustion in transplant. Higher levels of exhausted T cells have been associated with better graft function in kidney transplant recipients. In contrast, reinvigorating exhausted T cells by immune checkpoint blockade therapies, while promoting tumor clearance, increases the risk of acute rejection. Lymphocyte depletion and high alloantigen load have been identified as major drivers of T-cell exhaustion. This could account, at least in part, for the reduced rates of acute rejection in organ transplant recipients induced with thymoglobulin and for the pro-tolerogenic effects of a large organ such as the liver. Among the drugs that are widely used for maintenance immunosuppression, calcineurin inhibitors have a contrasting inhibitory effect on exhaustion of T cells, while the influence of mTOR inhibitors is still unclear. Harnessing or encouraging the natural processes of exhaustion may provide a novel strategy to promote graft survival and transplantation tolerance.

Subcutaneous nanotherapy repurposes the immunosuppressive mechanism of rapamycin to enhance allogeneic islet graft viability

Standard oral rapamycin (that is, Rapamune) administration is plagued by poor bioavailability and broad biodistribution. Thus, this pleotropic mammalian target of rapamycin (mTOR) inhibitor has a narrow therapeutic window and numerous side effects and provides inadequate protection to transplanted cells and tissues. Furthermore, the hydrophobicity of rapamycin limits its use in parenteral formulations. Here, we demonstrate that subcutaneous delivery via poly(ethylene glycol)-b-poly(propylene sulfide) polymersome nanocarriers significantly alters rapamycin's cellular biodistribution to repurpose its mechanism of action for tolerance, instead of immunosuppression, and minimize side effects. While oral rapamycin inhibits T cell proliferation directly, subcutaneously administered rapamycin-loaded polymersomes modulate antigen presenting cells in lieu of T cells, significantly improving maintenance of normoglycemia in a clinically relevant, major histocompatibility complex-mismatched, allogeneic, intraportal (liver) islet transplantation model. These results demonstrate the ability of a rationally designed nanocarrier to re-engineer the immunosuppressive mechanism of a drug by controlling cellular biodistribution.

Small molecules and their impact in drug discovery: A perspective on the occasion of the 125th anniversary of the Bayer Chemical Research Laboratory

The year 2021 marks the 125th anniversary of the Bayer Chemical Research Laboratory in Wuppertal, Germany. A significant number of prominent small-molecule drugs, from aspirin to Xarelto, have emerged from this research site. In this review, we shed light on historic cornerstones of small-molecule drug research, discussing current and future trends in drug discovery as well as providing a personal outlook on the future of drug research with a focus on small molecules.

The Immunomodulating Effects of Thalidomide and Dexamethasone in a Murine Cardiac Allograft Transplantation Model

PURPOSE

The immunomodulatory effects of thalidomide (TM) and dexamethasone (DX) on immune cells and their co-stimulatory, co-inhibitory molecules in vitro and in vivo have been previously reported. The current study investigated the effects of TM and the combinatorial treatment with DX on immune cells using a murine cardiac allograft transplantation model.

MATERIALS AND METHODS

Intraabdominal transplant of cardiac allografts from BALB/c (H-2^d) donors to C57BL/6 (H-2^b) recipients was performed. After transplantation, mice were injected daily with TM or DX or a combination of both TM and DX (TM/DX) by intraperitoneal route until the time of graft loss. CD4⁺ T cell subsets and CD11c⁺ cells in the peripheral blood mononuclear cells and spleen were examined and quantified with flow cytometry. Serum IL-6 levels were measured by enzyme-linked immunosorbent assay on day 7.

RESULTS

The mean graft survivals were 6.86 days in the untreated group, and 10.0 days in the TM/DX group (p<0.001). The TM/DX treatment affected the CD4⁺ T cell subsets without suppressing the total CD4⁺ T cell population. The CD4⁺FOXP3⁺/CD4⁺CD44^hi T cell ratio increased. Increase in cell counts and median fluorescence intensity on CD11c⁺CD85k⁺ with TM/DX were observed. The inhibition of pro-inflammatory cytokine interleukin-6 was also observed.

CONCLUSION

These outcomes suggest the immunomodulating effect of the TM/DX combinatorial treatment. In conclusion, TM/DX combination may be a promising immunomodulatory approach for preventing allograft rejection and improving graft survival by inducing tolerance in transplantation.

Reducing the Pill Burden: Immunosuppressant Adherence and Safety after Conversion from a Twice-Daily (IR-Tac) to a Novel Once-Daily (LCP-Tac) Tacrolimus Formulation in 161 Liver Transplant Patients

Non-adherence to immunosuppressant therapy reduces long-term graft and patient survival after solid organ transplantation. The objective of this 24-month prospective study was to determine adherence, efficacy and safety after conversion of stable liver transplant (LT) recipients from a standard twice-daily immediate release Tacrolimus (IR-Tac) to a novel once-daily life cycle pharma Tacrolimus (LCP-Tac) formulation. We converted a total of 161 LT patients at baseline, collecting Tacrolimus trough levels, laboratories, physical examination data and the BAASIS^© questionnaire for self-reported adherence to immunosuppression at regular intervals. With 134 participants completing the study period (17% dropouts), the overall adherence to the BAASIS^© increased by 57% until month 24 compared to baseline (51% vs. 80%). Patients who required only a morning dose of their concomitant medications reported the largest improvement in adherence after conversion. The intra-patient variability (IPV) of consecutive Tacrolimus trough levels after conversion did not change significantly compared to pre-conversion levels. Despite reducing the daily dose by 30% at baseline as recommended by the manufacturer, Tac-trough levels remained stable, reflected by an increase in the concentration-dose (C/D) ratio. No episodes of graft rejection or loss occurred. Our data suggest that the use of LCP-Tac in liver transplant patients is safe and can increase adherence to immunosuppression compared to conventional IR-Tac.

Multiplex Immunofluorescence Assay of Infiltrating Mononu-Clear Cell Subsets in Acute T-Cell-Mediated Rejection and BK Virus-Associated Nephropathy in the Allograft Kidney

Renal allograft biopsy is the gold standard procedure for diagnosis of kidney rejection via specific pathological changes. To provide a better assessment of immunologic events in acute T-cell-mediated rejection (acute TCMR) and BK virus-associated nephropathy (BKVAN) cases, we used multiplex immunofluorescence staining to identify infiltrating mononuclear cell subsets in the cortex area of transplanted kidneys. Antibodies to CD4, CD8, CD20, CD68, Foxp3, and cytokeratin were used. In cortical interstitium, CD8+ cells were significantly more prevalent in acute TCMR than BKVAN cases (34% vs. 22.8%, p = 0.034). In medulla, CD20+ cells were significantly more prevalent in BKVAN than acute TCMR cases (51.9% vs. 11.3%, p = 0.028).

Immunotherapy in liver transplantation for hepatocellular carcinoma: Pros and cons

Liver transplantation (LT) has emerged as a curative strategy for hepatocellular carcinoma (HCC), but contributes to a higher predisposition to HCC recurrence in the immunosuppression context, especially for tumors beyond the Milan criteria. Although immunotherapy has dramatically improved survival for immunocompetent patients and has become the standard of care for a variety of tumors, including HCC, it is mainly used outside the scope of organ transplantation owing to potentially fatal allograft rejection. Nevertheless, accumulative evidence has expanded the therapeutic paradigms of immunotherapy for HCC, from downstaging or bridging management in the pretransplant setting to the salvage or adjuvant strategy in the posttransplant setting. Generally, immunotherapy mainly includes immune checkpoint inhibitors (ICIs), adoptive cell transfer (ACT) and vaccine therapy. ICIs, followed by ACT, have been most investigated in LT, with some promising results. Because of the complex tumor microenvironment and immunoreactivity when immunosuppressants are combined with immunotherapy, it is difficult to reach formulations for immunosuppressant adjustment and the optimal selection of immunotherapy as well as patients. In addition, the absence of effective biomarkers for identifying rejection and tumor response is still an unresolved barrier to successful clinical immunotherapy applications for LT. In this review, we comprehensively summarize the available evidence of immunotherapy used in LT that is specific to HCC. Moreover, we discuss clinically concerning issues regarding the concurrent goals of graft protection and antitumor response.

The spatially resolved transcriptional profile of acute T cell-mediated rejection in a kidney allograft

Analysis of the transcriptional profile of graft biopsies represents a promising strategy to study T cell-mediated-rejection (TCMR), also known as acute cellular rejection. However, bulk RNA sequencing of graft biopsies may not capture the focal nature of acute rejection. Herein, we used the whole exome GeoMX Digital Space Profiling platform to study five tubular and three glomerular regions of interest in the kidney graft biopsy from a patient with a chronic-active TCMR episode and in analogous areas from two different normal kidney control biopsies. All kidney sections were from paraffin blocks. Overall, inflammatory genes were significantly upregulated in the tubular areas of the TCMR biopsy and showed an enrichment for gene-ontology terms associated with T-cell activation, differentiation, and proliferation. Enrichment analysis of the 100 genes with the highest coefficient of variation across the TCMR tubular regions of interest revealed that these highly variable genes are involved in kidney development and injury and interestingly do not associate with the 2019 Banff classification pathology scores within the individual regions of interest. Spatial transcriptomics allowed us to unravel a previously unappreciated variability across different areas of the TCMR biopsy related to the graft response to the alloimmune attack, rather than to the immune cells. Thus, our approach has the potential to decipher clinically relevant, new pathogenic mechanisms, and therapeutic targets in acute cellular rejection and other kidney diseases with a focal nature.

The Biology and Molecular Basis of Organ Transplant Rejection

Allograft rejection is defined as tissue injury in a transplanted allogeneic organ produced by the effector mechanisms of the adaptive alloimmune response. Effector T lymphocytes and IgG alloantibodies cause two different types of rejection that can occur either individually or simultaneously: T cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR). In TCMR, cognate effector T cells infiltrate the graft and orchestrate an interstitial inflammatory response in the kidney interstitium in which effector T cells engage antigen-presenting myeloid cells, activating the T cells, antigen-presenting cells, and macrophages. The result is intense expression of IFNG and IFNG-induced molecules, expression of effector T cell molecules and macrophage molecules and checkpoints, and deterioration of parenchymal function. The diagnostic lesions of TCMR follow, i.e. interstitial inflammation, parenchymal deterioration, and intimal arteritis. In ABMR, HLA IgG alloantibodies produced by plasma cells bind to the donor antigens on graft microcirculation, leading to complement activation, margination, and activation of NK cells and neutrophils and monocytes, and endothelial injury, sometimes with intimal arteritis. TCMR becomes infrequent after 5-10 years post-transplant, probably reflecting adaptive mechanisms such as checkpoints, but ABMR can present even decades post-transplant. Some rejection is triggered by inadequate immunosuppression and non-adherence, challenging the clinician to target effective immunosuppression even decades post-transplant.

Induction Therapy and Therapeutic Antibodies

Prevention of allograft rejection is one of the crucial goals in solid organ transplantation to ensure durability of the graft and is chiefly mediated by cellular and humoral pathways targeting cell surface alloantigens. The risk of rejection is highest in the first post-transplant year and wanes with time albeit the risk always exists and varies with the type of organ transplanted. Induction therapies refer to the use of high-intensity immunosuppression in the immediate post-operative period to mitigate the highest risk of rejection. This term encompasses chiefly the use of antibody therapies directed against one of the key pathways in T-cell activation or abrogating effects of circulating alloantibodies. These antibodies carry more potent immunomodulatory effect than maintenance immunosuppressive therapy alone and many of them lead to durable immune cell depletion. A variety of monoclonal and polyclonal antibodies have been utilized for use not only for induction therapy, but also for treatment of allograft rejection when it occurs and as components of desensitization therapy before and after transplantation to modulate circulating alloantibodies.

Avaliação da nefrotoxicidade pelo tacrolimus e micofenolato mofetil associados à isquemia e reperfusão renal: estudo experimental em ratos

RESUMO Objetivo: avaliar a toxicidade renal causada pelo tacrolimus e micofenolato mofetil (MMF) em um modelo de isquemia e reperfusão de rim único. Método: estudo experimental utilizando ratos Wistar, submetidos á nefrectomia direita e isquemia renal esquerda por 20 minutos, separados em grupos no pós- operatório (PO): 1) Controle (não operados); 2) Sham (operados, sem droga PO); 3) TAC0.1, TAC1 e TAC10, administrado tacrolimus no PO nas doses 0,1mg/kg, 1mg/kg e 10mg/kg via gavagem, respectivamentae; 4) MMF, administrado micofenolato mofetil 20mg/kg; 5) MMF/TAC1 e MMF/TAC0.5, com associação de micofenolato mofetil 20mg/kg e tacrolimus 1mg/kg e 0,5mg/kg, respectivamente. Foram mortos no 14º PO e retirado rim para análise do estresse oxidativo tecidual, pela dosagem de glutationa reduzida (GSH), lipoperoxidação (LPO) e carbonilação de proteínas (PCO), e análise histológica por estereologia glomerular (Densidade de volume glomerular, Densidade numérica glomerular e Volume glomerular médio). Foi avaliada função renal pela dosagem de creatinina e uréia séricas. Resultados: ambas drogas provocaram alteração na função renal, sendo a toxicidade do tacrolimus dosedependente. A toxicidade subaguda não mostrou alterações histológicas glomerulares significativas, sendo que houve hipertrofia renal e glomerular compensatória em todos os grupos exceto em TAC10. Conclusão: Ambas drogas provocam alteração na função renal. A morfometria e a estereologia glomerular mostraram interferência negativa dos imunossupressores durante a hipertrofia glomerular compensatória..

Impact of Genetic Polymorphisms at the Promoter area of IL-10 Gene on Tacrolimus Level in Jordanian Renal Transplantation Recipients

Background Tacrolimus is a widely used immunosuppressant that prevents the solid organ transplant rejection. The pharmacokinetics of Tacrolimus show considerable variability. interleukin-10 (IL-10), in the host’s immune response after transplantation contributes to the variable CYP3A-dependent drug disposition of Tacrolimus. In current study, our aim is to evaluate the impact of single nucleotide polymorphisms (SNP) in the promoter region of of IL-10 on Tacrolimus dose requirements and the Dose Adjusted Concentration (DAC) of Tacrolimus among kidney transplantation recipients.  Methods Blood levels of Tacrolimus were measured using Micorparticle Enzyme Immunoassay (MEIA) for six months post-transplantation. Genotyping analysis was utilized using specific Polymerase Chain Reaction (PCR) followed by sequencing methods for 98 Jordanian kidney transplant recipients. Results Genotyping frequencies of IL-10 (-592) were (CC/CA/AA: 38, 46.7, 15.2%); IL-10 (-819) were (CC/CT/TT: 40.4, 44.1, 15.1%); and IL-10 (-1082) were (AA/AG/GG: 42.6, 44.7, 12.8%). The impact of IL-10 (-1082) on Tacrolimus DAC was gender dependent. Men carrying at least one A allele had significantly lower DAC than men carrying GG genotyping only in the first month post-transplantation [88.2±32.1 vs. 117.5±22.5 ng/ml per mg/kg/day, p=0.04].. Conclusion Our current study showed that the interaction between gender and IL-10 -1082 affects Tacrolimus DAC in Jordanian kidney transplantation recipients during the first month post-transplantation.

Allorecognition and the spectrum of kidney transplant rejection

Detection of mismatched human leukocyte antigens by adaptive immune cells is considered as the main cause of transplant rejection, leading to either T-cell mediated rejection or antibody-mediated rejection. This canonical view guided the successful development of immunosuppressive therapies and shaped the diagnostic Banff classification for kidney transplant rejection that is used in clinics worldwide. However, several observations have recently emerged that question this dichotomization between T-cell mediated rejection and antibody-mediated rejection, related to heterogeneity in the serology, histology, and prognosis of the rejection phenotypes. In parallel, novel insights were obtained concerning the dynamics of donor-specific anti-human leukocyte antigen antibodies, the immunogenicity of donor-recipient non-human leukocyte antigen mismatches, and the autoreactivity against self-antigens. Moreover, the potential of innate allorecognition was uncovered, as exemplified by natural killer cell-mediated microvascular inflammation through missing self, and by the emerging evidence on monocyte-driven allorecognition. In this review, we highlight the gaps in the current classification of rejection, provide an overview of the expanding insights into the mechanisms of allorecognition, and critically appraise how these could improve our understanding and clinical approach to kidney transplant rejection. We argue that consideration of the complex interplay of various allorecognition mechanisms can foster a more integrated view of kidney transplant rejection and can lead to improved risk stratification, targeted therapies, and better outcome after kidney transplantation.

Pre-transplant maintenance dialysis duration and outcomes after kidney transplantation: A multicenter population-based cohort study

The association between pre-transplant dialysis duration and post-transplant outcomes may vary by the population and endpoints studied. We conducted a population-based cohort study using linked healthcare databases from Ontario, Canada including kidney transplant recipients (n = 4461) from 2004-2014. Our primary outcome was total graft failure (i.e., death, return to dialysis, or pre-emptive re-transplant). Secondary outcomes included death-censored graft failure, death with graft function, mortality, hospitalization for cardiovascular events, hospitalization for infection, and hospital readmission. We presented results by pre-transplant dialysis duration (pre-emptive transplant, and 0.01-1.43, 1.44-2.64, 2.65-4.25, 4.26-6.45, and 6.46-36.5 years, for quintiles 1-5). After adjusting for clinical characteristics, pre-emptive transplantation was associated with a lower rate of total graft failure (adjusted hazard ratio [aHR] 0.68, 95% CI: 0.46, 0.99), while quintile 4 was associated with a higher rate (aHR 1.31, 95% CI: 1.01, 1.71), when compared to quintile 1. There was no significant relationship between dialysis duration and death-censored graft failure, cardiovascular events, or hospital readmission. For death with graft function and mortality, quintiles 3-5 had a significantly higher aHR compared to quintile 1, while for infection, quintiles 2-5 had a higher aHR. Longer time on dialysis was associated with an increased rate of several adverse post-transplant outcomes. This article is protected by copyright. All rights reserved.

Bioactive compounds in green tea may improve transplant tolerance: A computational systems biology analysis

BACKGROUND

Green tea (Camellia sinensis) has bioactive compounds that have been shown to possess nutritive effects on various biomolecular processes such as immunomodulation. This research explores the immunomodulatory effects of green tea in reducing transplant rejection.

METHOD

The study employs computational systems biology: 1) to identify biomolecular mechanisms of immunomodulation in transplant rejection; 2) to identify the bioactive compounds of green tea and their specific effects on mechanisms of immunomodulation in transplant rejection; and, 3) to predict the quantitative effects of those bioactive compounds on immunomodulation in transplant rejection.

RESULTS

Three bioactive compounds of green tea - epicatechin (EC), gallic acid (GA), and epigallocatechin gallate (EGCG), were identified for their potential effects on immunomodulation of transplant rejection. Of the three, EGCG was the only one determined to enhance anti-inflammatory activity by: 1) upregulating synthesis of HO-1 that is known to promote Treg and Th2 phenotypes associated with enabling transplant tolerance; and, 2) downregulating pro-inflammatory cytokines IL-2, IL-17, IFN-γ, TNF-α, NO, IL-6, and IL-1β that are known to promote Th1 and Th17 phenotypes associated with transplant rejection.

CONCLUSIONS

To the best of our knowledge, this study provides the first molecular mechanistic understanding the clinical nutritive value of green tea, specifically the bioactive compound EGCG, in enabling transplant tolerance.

Immunosuppressants in Liver Transplant Recipients With Coronavirus Disease 2019: Capability or Catastrophe?-A Systematic Review and Meta-Analysis

Background: The probable impact of a maintenance immunosuppressant (IS) on liver transplant (LT) recipients with coronavirus disease 2019 (COVID-19) remains unexplored. Our specific aim was to approximate the prognosis of LT recipients with COVID-19 on the standard maintenance IS.

Method: We searched separate databases for the qualified studies in between December 2019 and June 25, 2021. Ultimately, a meta-analysis was carried out using a fixed-effect or random-effect model based on the heterogeneity.

Results: In a total of eight studies and 509 LT recipients with COVID-19, the pooled rates of severity and mortality during all the combined immunosuppressive therapies were 22.4 and 19.5%, respectively. Our study sufficiently showed that an immunosuppressive therapy in LT recipients with COVID-19 was significantly associated with a non-severe COVID-19 [odds ratio (OR): 11.49, 95% CI: 4.17–31.65; p < 0.001] and the survival of the patients (OR: 17.64, 95% CI: 12.85–24.22; p < 0.001). Moreover, mammalian target of rapamycin inhibitor (mTORi) typically had the lowest rate of severity and mortality compared to other ISs such as calcineurin inhibitors (CNIs), steroids, and antimetabolites, i.e., severity (13.5 vs. 21.1, 24.7, and 26.3%) and mortality (8.3 vs. 15, 17.2, and 12.1%), respectively. Contrary to the general opinions, our meta-analysis showed comorbidities such as diabetes, hypertension, cardiopulmonary disorders, chronic kidney disease (CKD), age >60, the duration of LT to the diagnosis of COVID-19, primary disease for LT, and obesity were not significantly associated with the severity and mortality in LT recipients with COVID-19 under an immunosuppressive therapy. However, our pooled analysis found that LT recipients with COVID-19 and without comorbidities have a less severe disease and low mortality rate compared to those with both COVID-19 and comorbidities.

Conclusions: In conclusion, LT recipients with COVID-19 undergoing immunosuppressive therapies are not significantly associated with the severity and mortality. Therefore, taking the risk of organ rejection into a key consideration, a complete withdrawal of the IS may not be wise. However, mycophenolate mofetil (MMF) might be discontinued or replaced from an immunosuppressive regimen with the CNIs- or mTORis-based immunosuppressive therapy in some selected LT recipients with COVID-19, depending upon the severity of the disease.

The mTOR inhibitor everolimus attenuates tacrolimus-induced renal interstitial fibrosis in rats

AIMS

Tacrolimus-a widely used immunosuppressant to prevent allograft rejection after organ transplantation-is nephrotoxic, increasing the risk of kidney injury accompanied by kidney fibrosis. The mammalian target of rapamycin (mTOR) inhibitor, everolimus, is an immunosuppressant used together with tacrolimus. Although mTOR signaling inhibition has been demonstrated to exhibit antifibrotic effects, the efficacy of everolimus against tacrolimus-induced kidney fibrosis has not been explored. Therefore, we evaluated the protective effects of everolimus against tacrolimus-induced kidney fibrosis.

MAIN METHODS

To assess antifibrotic effect of everolimus against tacrolimus-induced kidney fibrosis, male Wistar rats were subcutaneously administered vehicle or tacrolimus (5 mg/kg per day) and/or everolimus (0.2 mg/kg per day) for 2 weeks after bilateral renal ischemia for 45 min. The antifibrotic effect of everolimus was also assessed using rat kidney fibroblast cell line (NRK-49F).

KEY FINDINGS

Tacrolimus administration increased predominant profibrotic cytokine transforming growth factor-β (TGF-β) and fibroblast activation marker α-smooth muscle actin (α-SMA) expression and promoted the infiltration of macrophages in the kidney cortex, resulting in renal interstitial fibrosis in rats. Tacrolimus increased serum creatinine, blood urea nitrogen, kidney injury molecule-1 (KIM-1), and kidney injuries, such as tubular dilation, vacuolization, and glomerular atrophy. Everolimus administration attenuated tacrolimus-induced kidney fibrosis and the associated abnormalities. Everolimus strongly suppressed TGF-β-induced kidney fibroblast activation and extracellular matrix protein expression by the mTOR signaling inhibition.

SIGNIFICANCE

We demonstrated that everolimus attenuates tacrolimus-induced renal interstitial fibrosis in rats. Owing to its protective effect against tacrolimus-induced kidney fibrosis, everolimus may be useful when used concomitantly with tacrolimus.

Computational validation of ABCB1 gene polymorphism and its effect on tacrolimus dose concentration/levels in renal transplant individuals of South India

Patients with end-stage renal failure require hemodialysis and peritoneal dialysis; however, kidney transplantation is considered a better treatment option for renal failure patients, improving their quality of life and longevity. Among several potent immunosuppressive agents, tacrolimus (TAC) has shown progressive improvement in the graft survival rates after renal transplantation. Fifty kidney transplant patients undergoing TAC immunosuppressive treatment were included. The human genomic DNA was isolated using the phenol-chloroform extraction procedure. CYP3A5*6, CYP3A5*2, and ABCB1 exon 21 G2677 T/A polymorphisms were genotyped using the polymerase chain reaction-restriction fragment length polymorphism method. Fisher's exact test and Chi-square analysis were performed to analyze the data, where p < 0.05 was considered statistically significant. In addition, we implemented bioinformatics studies on ABCB1 protein to determine the mutation's effect sequentially and structurally. Among the genotyped single nucleotide polymorphisms (SNPs), SNPs of CYP3A5*2 and CYP3A5*6 did not vary in the studied population. The concentration/dose (C/D) ratio of TT genotype of the ABCB1 gene was higher (95% CI: 177.38-269.46) when compared to TA and AA. However, there were no substantial differences between the ABCB1 genotypes and TAC C/D ratio (p = 0.953). The TAC dose mg/kg/day (p = 0.002) and C/D ratio (p = 0.004) exhibited a statistically significant difference. However, no significant difference was found with respect to the ABCB1 gene between the non-toxicity and toxicity groups. Mutation and residue interaction analysis results showed that the S893T mutation destabilizes the ABCB1 protein, thus reducing the protein's flexibility. The present study demonstrated a substantial relationship between the TAC dose and C/D ratio, including the non-toxicity and toxicity groups. However, no possible correlation was observed between the ABCB1 gene polymorphism and renal transplant.

Impact of immunosuppression on the immune response to SARS-CoV-2 infection: A mechanistic study

The optimal management of immunosuppression in transplant patients infected with COVID-19 is unknown. We performed an in vitro study to determine the effect of individual immunosuppressive agents on SARS-CoV-2-specific T-cell cytokine expression. Convalescent peripheral blood mononuclear cells from eleven non-immunosuppressed patients with COVID-19 were preincubated with clinically relevant concentrations of immunosuppressive drugs (tacrolimus, mycophenolate, sirolimus, prednisone) and then stimulated with a SARS-CoV-2 peptide pool. Supernatants were analyzed by 14-plex high sensitivity T-cell cytokine array. With increasing concentrations of tacrolimus, there was a trend to reduction in the release of IL-2 (p = .0137), and IFN-γ (p = .0147) in response to peptide stimulation. There was also a subsequent trend toward a Th2 phenotype, indicated by lower IFN-γ:IL-13 ratio (p = .0663) and IFNγ:IL-4 ratio (p = .0176). Sirolimus appeared to be associated with a proinflammatory cytokine release, including TNF-α (p = .0027) and IL-1β (p = .0016), in response to SARS-CoV-2 peptides. In contrast, mycophenolate and prednisone did not influence the SARS-CoV-2-specific cytokine response. These are preliminary findings only, with larger studies required to inform clinical recommendations.

Therapeutic management of subcutaneous phaeohyphomycosis and chromoblastomycosis in kidney transplant recipients: a retrospective study of 82 cases in a single center

BACKGROUND

Melanized fungi are a distinct group of pathogens that cause infections like chromoblastomycosis and phaeohyphomycosis, especially in a state of immunosuppression including solid organ transplant recipients. Guidelines for the treatment of these infections are lacking, and there is no available standard recommendation.

OBJECTIVE

To evaluate the therapeutic aspects of subcutaneous melanized fungal infections in kidney transplant recipients.

METHODS

A retrospective medical record was performed for kidney transplant recipients with melanized fungal infection evaluated in a single institution from January 1996 to December 2018.

RESULTS

Eighty-two episodes were noticed in our series. The treatment of subcutaneous phaeohyphomycosis was managed by surgical excision without antifungal therapy in 34 cases (34/68; 50%), and the association of both methods occurred in 18 cases (18/68; 26.5%). A complete surgical excision without antifungal therapy was observed in six (6/14; 42.9%) episodes of chromoblastomycosis, and combined treatment was possible in three (3/14; 21.4%) cases. Five episodes of chromoblastomycosis and 16 episodes of phaeohyphomycosis were managed only with antifungal therapy.

CONCLUSION

Management depends on the dermatologic lesion, immunosuppression condition, and anatomical cleavage plane. The sample size is still small in order to dictate a guideline, but it can be hard to execute a larger study given the rarity of this group of infections.

Characteristics, management, and outcome of pediatric patients with post-transplant lymphoproliferative disease-A 20 years' experience from Austria

BACKGROUND

Management of pediatric post-transplantation lymphoproliferative disorder (PTLD) after hematopoietic stem cell (HSCT) and solid organ transplantation (SOT) is challenging.

AIM

This study of 34 PTLD patients up to 19-years old diagnosed in Austria from 2000 to 2018 aimed at assessing initial characteristics, therapy, response, and outcome as well as prognostic markers of this rare pediatric disease.

METHODS AND RESULTS

A retrospective data analysis was performed. Types of allografts were kidney (n = 12), liver (n = 7), heart (n = 5), hematopoietic stem cells (n = 4), lungs (n = 2), multi-visceral (n = 2), small intestine (n = 1), and vessels (n = 1). Eighteen/34 were classified as monomorphic PTLD, with DLBCL accounting for 15 cases. Polymorphic disease occurred in nine, and non-destructive lesions in six cases. One patient had a non-classifiable PTLD. Thirteen/34 patients are surviving event-free in first remission (non-destructive, n = 4/6; polymorphic, n = 4/9; monomorphic, n = 6/18). Fourteen/34 patients lacked complete response to first-line therapy, of whom seven died. Four/34 patients relapsed, of whom two died. In 3/34 patients, death occurred as a first event. The 5-year overall and event-free survival rates were 64% ± 9% and 35% ± 9% for the whole cohort. Among all parameters analyzed, only malignant disease as the indication for transplantation had a significantly poor influence on survival.

CONCLUSIONS

This study shows PTLD still to be a major cause of mortality following SOT or HSCT in children. A continued understanding of the molecular biology of the disease shall allow to decrease treatment intensity for lower risk patients and to identify patients who may benefit from newer therapy approaches to improve outcome and decrease morbidity.

Native Kidney Hydronephrosis Is Associated with Upper Urinary Tract Urothelial Carcinoma in Post-Kidney Transplantation Patients

Background: Upper urinary tract urothelial carcinoma (UTUC) is the most common malignancy occurring after kidney transplantation (KT) in Taiwan. The aim of this study was to investigate the association between native kidney hydronephrosis and UTUC in post-KT patients. Methods: From 2003 to 2018, we conducted a retrospective cohort study that enrolled 1005 post-KT patients, 67 of whom were subsequently diagnosed with UTUC. We divided patients into two groups based on whether or not they had UTUC. Multivariate analysis and Kaplan-Meier plot were used to evaluate if native kidney hydronephrosis was associated with post-KT UTUC. Results: The total cohort consisted of 612 men (60.9%) and 393 women (39.1%) with a mean age of 48.2 ± 12.0 at KT. The mean follow-up time was 118.6 ± 70.2 months, and mean time from KT to UTUC was 7.53 years. There was a significant gender difference with a female predominance among the UTUC patients (73.1% versus 26.9%, p < 0.001). Native kidney hydronephrosis occurred more frequently in the UTUC group (68.7% versus 4.8%, p < 0.001). Multivariate analysis showed that native kidney hydronephrosis and female gender were significantly associated with UTUC with odds ratios of 35.32 (95% CI, 17.99–69.36; p < 0.001) and 3.37 (95% CI, 1.55–7.29; p = 0.002), respectively. UTUC in the post-KT patients also showed aggressive pathological characteristics and a tendency toward bilateral lesions (41.8%). Conclusions: Native kidney hydronephrosis is significantly associated with post-KT UTUC patients in Taiwan. Native kidney hydronephrosis may be a deciding factor for standard nephroureterectomy and bladder cuff excision in selected patients. Nevertheless, almost half of the patients with kidney hydronephrosis do not present with UTUC at the end of our study.

An overview of the efficacy and safety of everolimus in adult solid organ transplant recipients

As the risk of graft loss due to acute rejection has declined, the goal of post-transplant management has switched to long-term preservation of organ function. Minimizing calcineurin inhibitor (CNI)-related nephrotoxicity is a key component of this objective. Everolimus is a mammalian target of rapamycin inhibitor/proliferation-signal inhibitor with potent immunosuppressive and anti-proliferative effects. It has been widely investigated in large randomized clinical studies that have shown it to have similar anti-rejection efficacy compared with standard-of-care regimens across organ transplant indications. With demonstrated potential to facilitate the reduction of CNI therapy and preserve renal function, everolimus is an alternative to the current standard-of-care CNI-based regimens used in de novo and maintenance solid organ transplantation recipients. Here, we provide an overview of the evidence from the everolimus clinical study program across kidney, liver, heart, and lung transplants, as well as other key data associated with its use in CNI reduction strategies in adult transplant recipients.

The Kv1.3 K+ channel in the immune system and its "precision pharmacology" using peptide toxins

Since the discovery of the Kv1.3 voltage-gated K⁺ channel in human T cells in 1984, ion channels are considered crucial elements of the signal transduction machinery in the immune system. Our knowledge about Kv1.3 and its inhibitors is outstanding, motivated by their potential application in autoimmune diseases mediated by Kv1.3 overexpressing effector memory T cells (e.g., Multiple Sclerosis). High affinity Kv1.3 inhibitors are either small organic molecules (e.g., Pap-1) or peptides isolated from venomous animals. To date, the highest affinity Kv1.3 inhibitors with the best Kv1.3 selectivity are the engineered analogues of the sea anemone peptide ShK (e.g., ShK-186), the engineered scorpion toxin HsTx1[R14A] and the natural scorpion toxin Vm24. These peptides inhibit Kv1.3 in picomolar concentrations and are several thousand-fold selective for Kv1.3 over other biologically critical ion channels. Despite the significant progress in the field of Kv1.3 molecular pharmacology several progressive questions remain to be elucidated and discussed here. These include the conjugation of the peptides to carriers to increase the residency time of the peptides in the circulation (e.g., PEGylation and engineering the peptides into antibodies), use of rational drug design to create novel peptide inhibitors and understanding the potential off-target effects of Kv1.3 inhibition.

Circulating NKG2C + NK cell expressing CD107a/LAMP-1 subsets at the onset of CMV reactivation in seropositive kidney transplant recipients

Cytomegalovirus (CMV) infection contributes to morbidity and mortality among kidney transplant recipients. Natural killer (NK) cells can battle against CMV in kidney transplant recipients (KTRs). This study aimed to analyze the association between CMV reactivation and the proportion of NK cell subsets and their activity. In a cross-sectional study, ten CMV reactivated KTRs, and ten non- CMV reactivated ones were recruited. Ten matched healthy controls were also included in this cohort. The presence of anti-CMV-IgG Ab in both KTR subgroups from seronegative donors and healthy controls was determined. The frequency of distinct subsets of memory-like NK cells was analyzed through NKG2C, NKG2A, and CD57 using flow cytometry. The activity of NK cells was evaluated after stimulation via coculture with K562 cell line and then assessment of the frequency of CD107a and granzyme B. The mRNA levels of transcription factors, including T-bet, EAT, and inflammatory proteins, including IFN-γ and perforin contributing to NK cell activation, were also evaluated. Results showed a significantly lower frequency of NKG2C + NKG2A-CD57+ NK cell population in CMV-reactivated KTRs compared to non-reactivated ones (P-value:0.003). NKG2C+ NK cells expressing CD107a/LAMP-1 significantly was increased in CMV-reactivated KTRs compared to non-reactivated ones (P-value: 0.0002). The mRNA level of IFN-γ had a significant increase in the CMV-reactivated KTRs vs. nonreactive ones (P-value: 0.004). Finally, evaluation of the NK cells' cytotoxicity and activity through assessment of CD107a/LAMP-1 expression and IFN-γ secretion may be helpful for the identification of the risk of CMV reactivation in KTRs.

Drug-Drug Interaction between Tacrolimus and Vonoprazan in Kidney Transplant Recipients

Kidney transplant recipients with tacrolimus-based immunosuppressive therapy are often treated with proton-pump inhibitors (PPIs) to prevent gastric ulcer complications. Vonoprazan, a potassium-competitive acid blocker, is a novel PPI possessing different metabolic pathways from conventional PPIs (e.g., omeprazole, lansoprazole and rabeprazole). However, no data are available on the change in blood concentration of tacrolimus after switching rabeprazole, a conventional PPI, to vonoprazan coadministration in the initial period of post-transplantation. This is a retrospective study of 18 kidney transplant recipients. The blood concentration and the concentration to dose (C/D) ratio of tacrolimus were compared before and after switching from rabeprazole to vonoprazan. Impacts of CYP2C19 and CYP3A5 genetic polymorphisms on the drug-drug interaction were also examined. The median (range) trough concentration of tacrolimus was significantly increased from 5.2 (3.6-7.4) to 8.1 (6.1-11.7) ng/mL (p < 0.0005) after switching from rabeprazole to vonoprazan. The C/D ratio of tacrolimus was also significantly increased from 38.1 (16.5-138.1) to 48.9 (26.2-207.2) (p < 0.0005). The percent changes of tacrolimus concentrations and C/D were 65.8% and 41.8%, respectively. CYP2C19 and CYP3A5 genetic polymorphisms did not affect the change in concentration and C/D ratio of tacrolimus. The present study indicates that vonoprazan coadministration increases the tacrolimus concentration regardless of CYP2C19 or CYP3A5 genetic polymorphisms. Thus, frequent monitoring of blood tacrolimus concentration is required when vonoprazan is introduced as an intensive gastric acid blocker in the early phase of post-transplantation.

Transplantation and immunosuppression: a review of novel transplant-related immunosuppressant drugs

Immunosuppressive drugs used in the transplantation period are generally defined as induction and maintenance therapy. The use of immunosuppressants, which are particularly useful and have fewer side effects, decreased both mortality and morbidity. Many drugs such as steroids, calcineurin inhibitors (cyclosporine-A, tacrolimus), antimetabolites (mycophenolate mofetil, azathioprine), and mTOR inhibitors (sirolimus, everolimus) are used as immunosuppressive agents. Although immunosuppressant drugs cause many side effects such as hypertension, infection, and hyperlipidemia, they are the agents that should be used to prevent organ rejection. This shows the importance of individualized drug use. The optimal immunosuppressive therapy post-transplant is not established. Therefore, discovering less toxic but more potent new agents is of great importance, and new experimental and clinical studies are needed in this regard.Our review discussed the mechanism of immunosuppressants, new agents' discovery, and current therapeutic protocols in the transplantation.

Vaccination in Children With Autoimmune Disorders and Treated With Various Immunosuppressive Regimens: A Comprehensive Review and Practical Guide

Children with autoimmune disorders are especially at risk of vaccine-preventable diseases due to their underlying disease and the immunosuppressive treatment often required for a long period. In addition, vaccine coverage remains too low in this vulnerable population. This can be explained by a fear of possible adverse effects of vaccines under immunosuppression, but also a lack of data and clear recommendations, particularly with regard to vaccination with live vaccines. In this review, the latest literature and recommendations on vaccination in immunosuppressed children are discussed in detail, with the aim to provide a set of practical guidelines on vaccination for specialists caring for children suffering from different autoimmune disorders and treated with various immunosuppressive regimens.

Optimal Immunosuppression Strategy in the Sensitized Kidney Transplant Recipient

Patients with previous sensitization events against anti-human leukocyte antigens (HLA) often have circulating anti-HLA antibodies. Following organ transplantation, sensitized patients have higher rates of antibody-mediated rejection (AMR) compared to those who are non-sensitized. More stringent donor matching is required for these patients, which results in a reduced donor pool and increased time on the waitlist. Current approaches for sensitized patients focus on reducing preformed antibodies that preclude transplantation; however, this type of desensitization does not modulate the primed immune response in sensitized patients. Thus, an optimized maintenance immunosuppressive regimen is necessary for highly sensitized patients, which may be distinct from non-sensitized patients. In this review, we will discuss the currently available therapeutic options for induction, maintenance, and adjuvant immunosuppression for sensitized patients.

Characteristics of T- and NK-cell Lymphomas After Renal Transplantation: A French National Multicentric Cohort Study

BACKGROUND

Posttransplant lymphoproliferative disorders (PTLDs) encompass a spectrum of heterogeneous entities. Because the vast majority of cases PTLD arise from B cells, available data on PTLD of T or NK phenotype (T/NK-cell PTLD) are scarce, which limits the quality of the management of these patients.

METHODS

All adult cases of PTLD diagnosed in France were prospectively recorded in the national registry between 1998 and 2007. Crosschecking the registry data with 2 other independent national databases identified 58 cases of T/NK-cell PTLD. This cohort was then compared with (i) the 395 cases of B-cell PTLD from the registry, and of (ii) a cohort of 148 T/NK-cell lymphomas diagnosed in nontransplanted patients.

RESULTS

T/NK-cell PTLD occurred significantly later after transplantation and had a worse overall survival than B-cell PTLD. Two subtypes of T/NK-cell PTLD were distinguished: (i) cutaneous (28%) and (ii) systemic (72%), the latter being associated with a worse prognosis. Compared with T/NK-cell lymphomas of nontransplanted patients, overall survival of systemic T/NK-cell PTLD was worse (hazard ratio: 2.64 [1.76-3.94]; P < 0.00001).

CONCLUSIONS

This difference, which persisted after adjustment on tumoral mass, histological subtype, and extension of the disease at diagnosis could be explained by the fact that transplanted patients were less intensively treated and responded less to chemotherapy.

The Efficacy of COVID-19 Vaccines in Chronic Kidney Disease and Kidney Transplantation Patients: A Narrative Review

The SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic has posed a huge threat to global health because of its rapid spread and various mutant variants. Critical illness occurs in the elderly and vulnerable individuals, such as those with chronic kidney disease. The severity of SARS-CoV-2 infection is associated with the severity of chronic kidney disease (CKD)and even kidney transplantation (KT) because of the chronic use of immunosuppressive agents. To develop adaptive immunity against SARS-CoV-2, vaccination against the spike protein is important. Current phase III trials of vaccines against SARS-CoV-2 have not focused on a specific group of individuals, such as patients with CKD or those undergoing dialysis or kidney transplantation. Chronic use of immunosuppressive agents might disturb the immune response to the SARS-CoV-2 spike protein. On the basis of limited evidence, the immune compromised status of CKD patients might decrease neutralizing antibody development after a single dose of a specific vaccine. Boosting dosage more than the protocol might increase the titer of the neutralizing antibody in CKD patients. Further evidence is needed to understand the factors disturbing the immunogenicity of the SARS-CoV-2 vaccine, and CKD patients should receive the recommended dose of the SARS-CoV-2 vaccine due to their relatively immune compromised status.

Entrustable professional activities for pharmacy students: A primer for solid organ transplant preceptors

DISCLAIMER

In an effort to expedite the publication of articles , AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

The role of a solid organ transplant pharmacist is multifaceted and translates to diverse experiential and elective learning experiences that can be provided to pharmacy learners. Here we provide a guide to integrating pharmacy students into patient care and other pharmacist activities in solid organ transplantation.

SUMMARY

Thoughtful incorporation of learners into clinical practice and clinical research creates a positive learning environment for pharmacy students that can foster the development of core skills necessary for students to become "practice-ready" and "team-ready" pharmacy graduates and can equip them with valuable skills to incorporate into the specialty practice areas and careers they pursue. To help develop these educational experiences, attention to the list of core entrustable professional activities (EPAs) established by the American Association of Colleges of Pharmacy can help create a rich environment of learning with carefully cultivated tasks. Furthermore, learners can serve as transplant pharmacist extenders to assist in overall patient care and multidisciplinary involvement on the transplant team. This article serves as a "how-to" guide for applying the EPA framework to integrating pharmacy students in patient care and other pharmacist activities in solid organ transplantation and other specialty practice areas.

CONCLUSION

As pharmacy preceptors design and operationalize their teaching to incorporate EPAs, they can benefit from recommendations tailored to specialty practice areas such as solid organ transplantation. Students may start and finish these experiences at different EPA levels, but continuance of training will allow them to achieve the final EPA level across the 6 EPA domains.

SARS-CoV-2-specific serological and functional T cell immune responses during acute and early COVID-19 convalescence in solid organ transplant patients

The description of protective humoral and T cell immune responses specific against SARS-CoV-2 has been reported among immunocompetent (IC) individuals developing COVID-19 infection. However, its characterization and determinants of poorer outcomes among the at-risk solid organ transplant (SOT) patient population have not been thoroughly investigated. Cytokine-producing T cell responses, such as IFN-γ, IL-2, IFN-γ/IL-2, IL-6, IL-21, and IL-5, against main immunogenic SARS-CoV-2 antigens and IgM/IgG serological immunity were tracked in SOT (n = 28) during acute infection and at two consecutive time points over the following 40 days of convalescence and were compared to matched IC (n = 16) patients admitted with similar moderate/severe COVID-19. We describe the development of a robust serological and functional T cell immune responses against SARS-CoV-2 among SOT patients, similar to IC patients during early convalescence. However, at the infection onset, SOT displayed lower IgG seroconversion rates (77% vs. 100%; p = .044), despite no differences on IgG titers, and a trend toward decreased SARS-CoV-2-reactive T cell frequencies, especially against the membrane protein (7 [0-34] vs. 113 [15-245], p = .011, 2 [0-9] vs. 45 [5-74], p = .009, and 0 [0-2] vs. 13 [1-24], p = .020, IFN-γ, IL-2, and IFN-γ/IL-2 spots, respectively). In summary, our data suggest that despite a certain initial delay, SOT population achieve comparable functional immune responses than the general population after moderate/severe COVID-19.

Missing Self-Induced Microvascular Rejection of Kidney Allografts: A Population-Based Study

BACKGROUND

Circulating anti-HLA donor-specific antibodies (HLA-DSA) are often absent in kidney transplant recipients with microvascular inflammation (MVI). Missing self, the inability of donor endothelial cells to provide HLA I-mediated signals to inhibitory killer cell Ig-like receptors (KIRs) on recipient natural killer cells, can cause endothelial damage in vitro, and has been associated with HLA-DSA-negative MVI. However, missing self's clinical importance as a nonhumoral trigger of allograft rejection remains unclear.

METHODS

In a population-based study of 924 consecutive kidney transplantations between March 2004 and February 2013, we performed high-resolution donor and recipient HLA typing and recipient KIR genotyping. Missing self was defined as the absence of A3/A11, Bw4, C1, or C2 donor genotype, with the presence of the corresponding educated recipient inhibitory KIR gene.

RESULTS

We identified missing self in 399 of 924 transplantations. Co-occurrence of missing self types had an additive effect in increasing MVI risk, with a threshold at two concurrent types (hazard ratio [HR], 1.78; 95% confidence interval [95% CI], 1.26 to 2.53), independent of HLA-DSA (HR, 5.65; 95% CI, 4.01 to 7.96). Missing self and lesions of cellular rejection were not associated. No HLA-DSAs were detectable in 146 of 222 recipients with MVI; 28 of the 146 had at least two missing self types. Missing self associated with transplant glomerulopathy after MVI (HR, 2.51; 95% CI, 1.12 to 5.62), although allograft survival was better than with HLA-DSA-associated MVI.

CONCLUSION

Missing self specifically and cumulatively increases MVI risk after kidney transplantation, independent of HLA-DSA. Systematic evaluation of missing self improves understanding of HLA-DSA-negative MVI and might be relevant for improved diagnostic classification and patient risk stratification.

Acute Versus Chronic Administration of Calcineurin-Inhibitors Differentially Affect T-Cell Function

BACKGROUND

Calcineurin-inhibitors (CNI) are used in renal transplant patients (RTX) to prevent rejection. CNI mainly suppress T-cell mediated immunity but very little is known about the impact of long-term treatment with CNI on T-cell function.

OBJECTIVE

We investigated the immunological effects of long-term CNI intake in RTX patients in comparison to short-term CNI administration in healthy controls (HC).

METHODS

Blood was drawn from 30 RTX patients with long-term CNI treatment. In addition, blood was sampled from HC with short-term CNI treatment (four dosages) before the first and 2 hours after the last CsA intake. T-cells were analyzed for cytokine production, proliferation, and CD25 expression.

RESULTS

Short-term CNI reduced T-cell derived IL-2 and IFNγ as well as T-cell proliferation in HC. IFNγ was not suppressed in patients with long-term CNI treatment. IL-2 production, CD25 expression, and T-cell proliferation were enhanced in long-term CNI patients.

CONCLUSION

Suppression of IFNγ/IL-2 and T-cell proliferation is weaker during long-term CNI treatment in patients compared to short-term treatment in healthy subjects. Enhanced CD25 expression may lower the threshold for T-cell activation during long-term CNI treatment.

ACTH treatment promotes murine cardiac allograft acceptance

Heart transplantation is the optimal therapy for patients with end-stage heart disease, but its long-term outcome remains inadequate. Recent studies have highlighted the importance of the melanocortin receptors (MCRs) in inflammation, but how MCRs regulate the balance between alloreactive T cells and Tregs, and whether they impact chronic heart transplant rejection, is unknown. Here, we found that Tregs express MC2R, and MC2R expression was highest among all MCRs by Tregs. Our data indicate that adrenocorticotropic hormone (ACTH), the sole ligand for MC2R, promoted the formation of Tregs by increasing the expression of IL-2Rα (CD25) in CD4⁺ T cells and activation of STAT5 in CD4⁺CD25⁺ T cells. ACTH treatment also improved the survival of heart allografts and increased the formation of Tregs in CD28KO mice. ACTH treatment synergized with the tolerogenic effect of CTLA-4–Ig, resulting in long-term survival of heart allografts and an increase in intragraft Tregs. ACTH administration also demonstrated higher prolongation of heart allograft survival in transgenic mouse recipients with both complete KO and conditional KO of PI3Kγ in T cells. Finally, ACTH treatment reduced chronic rejection markedly. These data demonstrate that ACTH treatment improved heart transplant outcomes, and this effect correlated with an increase in Tregs.

Renal transplant evaluation: multimodality imaging of post-transplant complications

With advancements in surgical techniques and immuno-suppression, renal transplantation is established as the most effective treatment option in patients with end-stage renal disease. Early detection of renal allograft complications is important for long-term graft survival. Late clinical presentation often causes diagnostic delays till the time allograft failure is advanced and irreversible. Imaging plays a key role in routine surveillance and in management of acute or chronic transplant dysfunction. Multimodality imaging approach is important with ultrasound-Doppler as the first-line imaging study in immediate, early and late post-transplant periods. Additional imaging studies are often required depending on clinical settings and initial ultrasound. Renal functional MRI is a rapidly growing field that has huge potential for early diagnosis of transplant dysfunction. Multiparametric MRI may be integrated in clinical practice as a noninvasive and comprehensive "one-stop" modality for early diagnosis and longitudinal monitoring of renal allograft dysfunctions, which is essential for guiding appropriate interventions to delay or prevent irreversible renal damage. With rapidly increasing numbers of renal transplantation along with improved patient survival, it is necessary for radiologists in all practice settings to be familiar with the normal appearances and imaging spectrum of anatomical and functional complications in a transplant kidney. Radiologist"s role as an integral part of multidisciplinary transplantation team continues to grow with increasing numbers of successful renal transplantation programs across the globe.

Similar quality in chronic kidney disease multidisciplinary follow-up between kidney

INTRODUCTION

Multidisciplinary clinics are the best approach towards Chronic Kidney Disease (CKD) patients in pre-dialysis phases. The few studies regarding kidney transplant recipients (KTR) compare multidisciplinary and non-multidisciplinary clinics.

METHODS

In this study, we compared the quality of multidisciplinary CKD care between 101 KTR and 101 propensity score-matched non-transplant pre-dialysis patients (PDP). Prevalence of patients without specific treatment at any time and percent time without specific treatment for CKD complications were the main outcomes and patient and kidney function survival, glomerular filtration rate (GFR) decline, prevalence of CKD-related complications, and percent time within therapeutic goals were the exploratory ones.

RESULTS

Time within most goals was similar between the groups, except for diastolic blood pressure (83.4 vs. 77.3%, RR 0.92, CI 0.88-0.97, p = 0.002) and hypertriglyceridemia (67.7 vs. 58.2%, OR 0.85, CI 0.78-0.93, p < 0.001), better in non-transplant PDP, and for proteinuria (92.7 vs. 83.5%, RR 1.1, CI 1.05-1.16, p < 0.001), better in KTR. Patient survival and GFR decline were similar between the groups, although non-transplant PDP tended to progress earlier to dialysis (9.9% vs. 6.9%, HR 0.39, p = 0.07, CI 0.14-1.08).

DISCUSSION

The similar findings between non-transplant PDP and KTR suggests that good and comparable quality of multidisciplinary is a valid strategy for promoting optimal clinical management of CKD-related complications in KTR.

Treatment optimization of maintenance immunosuppressive agents in pediatric renal transplant recipients

Introduction: Graft survival in pediatric kidney transplant patients has increased significantly within the last three decades, correlating with the discovery and utilization of new immunosuppressants as well as improvements in patient care. Despite these developments in graft survival for patients, there is still improvement needed, particularly in long-term care in pediatric patients receiving grafts from deceased donor patients. Maintenance immunosuppressive therapies have narrow therapeutic indices and are associated with high inter-individual and intra-individual variability.Areas covered: In this review, we examine the impact of pharmacokinetic variability on renal transplantation and its association with age, genetic polymorphisms, drug-drug interactions, drug-disease interactions, renal insufficiency, route of administration, and branded versus generic drug formulation. Pharmacodynamics are outlined in terms of the mechanism of action for each immunosuppressant, potential adverse effects, and the utility of pharmacodynamic biomarkers.Expert opinion: Acquiring abetter quantitative understanding of immunosuppressant pharmacokinetics and pharmacodynamic components should help clinicians implement treatment regimens to maintain the balance between therapeutic efficacy and drug-related toxicity.

Immune responses to the adjuvanted recombinant zoster vaccine in immunocompromised adults: a comprehensive overview

Immunocompromised (IC) persons are at increased risk for herpes zoster (HZ) and its complications, mainly due to impairment of cell-mediated immunity (CMI). The adjuvanted recombinant zoster vaccine (RZV) demonstrated efficacy against HZ in autologous hematopoietic stem cell transplant (auto-HSCT) recipients and hematologic malignancy (HM) patients. We review immune responses to RZV in 5 adult IC populations, 4 of which were receiving multiple, concomitant immunosuppressive medications: auto-HSCT and renal transplant recipients, HM and solid tumor patients, and human immunodeficiency virus-infected adults. Although administered in most cases when immunosuppression was near its maximum, including concomitantly with chemotherapy cycles, RZV induced robust and persistent humoral and, more importantly, CMI responses in all 5 IC populations. Based on the overall clinical data generated in older adults and IC individuals, RZV is expected to provide benefit in a broad adult population at risk for HZ.

Role of the IL-33/ST2 pathway in renal allograft rejection

The interleukin-33 (IL-33)/suppression of tumorigenicity 2 (ST2) pathway modulates immune response and inflammation, associated with allograft dysfunction and rejection. We hypothesized that IL-33/ST2 is a marker of renal allograft rejection and IL-33/ST2 expression may differ according to rejection type. IL-33/ST2 expression was measured in sera and kidney tissues from recipients with acute antibody-mediated rejection (AAMR), acute cell-mediated rejection (ACMR), chronic antibody-mediated rejection (CAMR), and healthy controls. The soluble ST2 and IL-33/ST2 expression levels were higher in participants with all three rejection types than in controls. Although the expression levels in recipients with AAMR and ACMR were significantly higher than those with CAMR, there was no significant difference between the expression levels in AAMR and ACMR. Although IL-33, IL-8, and fibronectin expression were significantly increased after the addition of the recipients' serum in primary cultured human renal proximal tubular epithelial cells, the levels decreased after treatment with an anti-ST2 antibody. Furthermore, the anti-ST2 antibody specifically suppressed the upregulation of the mixed lymphocyte reaction. Boyden chamber assays demonstrated that anti-ST2 antibody abrogated chemotaxis induced by recombinant IL-33. Thus, IL-33 and ST2 are potent mediators of rejection. Treatment with an anti-ST2 antibody ameliorates rejection and could be a potential therapeutic strategy for renal allograft rejection.

Blastomycosis in solid organ transplant recipients-A retrospective series from southeastern Wisconsin

Blastomycosis is a fungal infection caused primarily by Blastomyces dermatitis. The fungus is endemic to the Ohio, Mississippi, and St. Lawrence River areas of the United States. Organ transplant recipients are at risk of blastomycosis due to pharmacologic immunosuppression. Over a 20-year period, 30 cases of blastomycosis post-solid organ transplantation were identified at our center. The cumulative incidence of blastomycosis among SOT recipients was 0.99%. There was a male predominance (70% male) and a median age of 59 at the time of diagnosis. Regarding transplant type, 23 patients received kidney transplants, 4 received liver transplants, 2 received pancreas transplants and 1 received a heart transplant. Median time to blastomycosis identification post-transplant was 67.8 months (range: 1-188 months). Amphotericin B was used as initiation therapy in most cases, followed by itraconazole, voriconazole, or in select cases fluconazole or posaconazole maintenance therapy. Regarding comorbid conditions, 87% of patients had diabetes, 50% had congestive heart failure, and 20% had chronic pulmonary disease. Nine patients (30%) developed blastomycosis-related acute respiratory distress syndrome, 33% of these died with a median time to death of 22 days (range 20 days to 2 months); these were the only deaths attributable to blastomycosis.

Tacrolimus exposure windows responsible for Listeria monocytogenes infection susceptibility

Tacrolimus is widely used to prevent graft rejection after allogeneic transplantation by suppressing T cells in a non-antigen-specific fashion. Global T-cell suppression makes transplant recipients more susceptible to infection, especially infection by opportunistic intracellular pathogens. Infection followed by secondary challenge with the opportunistic intracellular bacterial pathogen, Listeria monocytogenes, was used to probe when tacrolimus most significantly impacts antimicrobial host defense. Tacrolimus-treated mice showed no difference in innate susceptibility following primary infection, whereas susceptibility to secondary challenge was significantly increased. Modifying the timing of tacrolimus initiation with respect to primary infection compared with secondary challenge showed significantly reduced susceptibility in tacrolimus-treated mice where tacrolimus was discontinued prior to secondary challenge. Thus, tacrolimus overrides protection against secondary infection primed by primary infection (and presumably live attenuated vaccines), with the most critical window for tacrolimus-induced infection susceptibility being exposure immediately prior to secondary challenge. These results have important implications for strategies designed to boost antimicrobial T-cell-mediated immunity in transplant recipients.

Sex differences in cancer risk and outcomes after kidney transplantation

Kidney transplant recipients (KTRs) experience a two- to four-fold increased risk of developing and dying from cancer compared with the general population. High cancer risk results from the interaction of both modifiable and non-modifiable factors. This mapping review explores the impact of sex disparity on cancer's increased incidence and mortality after kidney transplantation (KT). In terms of age, population-based studies indicate that younger recipients of both sexes experience a higher risk of cancer, but this is more pronounced in young women. On the contrary, older men are more likely to be diagnosed with cancer, although their increased risk is not statistically significant compared with the general population. Regarding cancer type, studies show an increased risk of Kaposi sarcoma, gynecologic and lung cancer in women, and bladder and kidney cancer in men. Immune-related cancers such as pos-transplant lymphoproliferative disorders and melanoma are increased in both sexes. Mortality also shows differences between sexes. Although cancer is the second cause of death in both male and female KTRs, studies show higher overall mortality in men and elderly recipients. However, the relative risk of cancer mortality compared with the general population is higher at a younger age, with disparate results regarding sex. Female KTRs appear to die at a younger age than males when compared with the general population. Differences in cancer rates by sex after renal transplantation need further studies. A better understanding of sex-specific differences in cancer epidemiology after KT could help nephrologists to better address pre-transplant counseling, to establish early surveillance programs, and to plan modifiable risk factors such as immunosuppression.