The use of extracorporeal photopheresis in solid organ transplantation-current status and future directions

Prevention and management of allograft rejection urgently require more effective therapeutic solutions. Current immunosuppressive therapies used in solid organ transplantation, while effective in reducing the risk of acute rejection, are associated with substantial adverse effects. There is, therefore, a need for agents that can provide immunomodulation, supporting graft tolerance, while minimizing the need for immunosuppression. Extracorporeal photopheresis (ECP) is an immunomodulatory therapy currently recommended in international guidelines as an adjunctive treatment for the prevention and management of organ rejection in heart and lung transplantations. This article reviews clinical experience and ongoing research with ECP for organ rejection in heart and lung transplantations, as well as emerging findings in kidney and liver transplantation. ECP, due to its immunomodulatory and immunosuppressive-sparing effects, offers a potential therapeutic option in these settings, particularly in high-risk patients with comorbidities, infectious complications, or malignancies.

Posttransplant complications: molecular mechanisms and therapeutic interventions

Posttransplantation complications pose a major challenge to the long-term survival and quality of life of organ transplant recipients. These complications encompass immune-mediated complications, infectious complications, metabolic complications, and malignancies, with each type influenced by various risk factors and pathological mechanisms. The molecular mechanisms underlying posttransplantation complications involve a complex interplay of immunological, metabolic, and oncogenic processes, including innate and adaptive immune activation, immunosuppressant side effects, and viral reactivation. Here, we provide a comprehensive overview of the clinical features, risk factors, and molecular mechanisms of major posttransplantation complications. We systematically summarize the current understanding of the immunological basis of allograft rejection and graft-versus-host disease, the metabolic dysregulation associated with immunosuppressive agents, and the role of oncogenic viruses in posttransplantation malignancies. Furthermore, we discuss potential prevention and intervention strategies based on these mechanistic insights, highlighting the importance of optimizing immunosuppressive regimens, enhancing infection prophylaxis, and implementing targeted therapies. We also emphasize the need for future research to develop individualized complication control strategies under the guidance of precision medicine, ultimately improving the prognosis and quality of life of transplant recipients.

Dendritic Cells: A Bridge between Tolerance Induction and Cancer Development in Transplantation Setting

Dendritic cells (DCs) are a heterogeneous group of antigen-presenting cells crucial for fostering allograft tolerance while simultaneously supporting host defense against infections and cancer. Within the tumor microenvironment, DCs can either mount an immune response against cancer cells or foster immunotolerance, presenting a dual role. In immunocompromised individuals, posttransplant malignancies pose a significant health concern, with DCs serving as vital players in immune responses against cancer cells. Both recipient- and donor-derived DCs play a critical role in the rejection process, infiltrating the transplanted organ and sustaining T-cell responses. The use of immunosuppressive drugs represents the predominant approach to control this immunological barrier in transplanted organs. Evidence has shed light on the immunopharmacology of these drugs and novel strategies for manipulating DCs to promote allograft survival. Therefore, comprehending the mechanisms underlying this intricate microenvironment and the effects of immunosuppressive therapy on DCs is crucial for developing targeted therapies to reduce graft failure rates. This review will delve into the fundamental immunobiology of DCs and provide a detailed exploration of their clinical significance concerning alloimmune responses and posttransplant malignancies.

Post-transplant malignancy: Focusing on virus-associated etiologies, pathogenesis, evidence-based management algorithms, present status of adoptive immunotherapy and future directions

Modern immunosuppression has led to a decrease in rejection rates and improved survival rates after solid organ transplantation. Increasing the potency of immunosuppression promotes post-transplant viral infections and associated cancers by impairing immune response against viruses and cancer immunoediting. This review reflects the magnitude, etiology and immunological characteristics of various virus-related post-transplant malignancies, emphasizing the need for future research. A multidisciplinary and strategic approach may serve best but overall literature evidence targeting it is sparse. However, the authors attempted to provide a more detailed update of the literature consensus for the prevention, diagnosis, management and surveillance of post-transplant viral infections and associated malignancies, with a focus on the current role of adoptive immunotherapy and the way forward. In order to achieve long-term patient and graft survival as well as superior post-transplant outcomes, collaborative research on holistic care of organ recipients is imperative.

Temporal trends of de novo urological malignancy in renal transplant recipients without a cancer history: A longitudinal cohort study

BACKGROUND

The incidence of malignancies after successful kidney transplantation has historically been higher than in the general population, with adverse impact on clinical outcomes. However, uncertainty remains as to which cancers occur at what time points after kidney transplantation.

METHODS

We conducted a longitudinal cohort study to investigate the temporal trends and topographic patterns of de novo malignancies to optimize surveillance protocols and improve transplant outcome in renal transplant recipients. Measurement of death and cancer events was performed to calculate the cumulative risk of events of interest.

RESULTS

Between 2000 and 2013, 3169 renal transplant recipients were retrospectively screened; 3035 (96%) of them met eligibility criteria and were evaluated with a follow-up of 27612 person-years. There was suboptimal overall survival and malignancy-free survival in renal transplant recipients compared to reference groups (HR: 1.65; 95% CI: 1.50-1.82; p < .001; HR: 2.33; 95% CI: 2.04-2.66; p < .001, respectively). Among renal transplant recipients, urological malignancies were predominant (57.5%), followed by digestive tract malignancies (21.4%). The cancer risks of the urinary bladder and upper urinary tract were lower in male subjects (HR: .48; 95% CI: .33-.72; p < .001; HR: .34; 95% CI: .20-.59; p < .001, respectively). The temporal trends of urological malignancies among renal transplant recipients were expressed in a bimodal pattern, with M-shaped peaks at 3 and 9 years, with gender disparity.

CONCLUSIONS

In renal transplant recipients, cancer occurrences are shown as M-shaped twin peaks. Our study highlights that specific customized 'targeted' strategies for cancer surveillance programs are required to optimize posttransplant care.

Immunosuppressive Therapy in Solid Organ Transplantation: Primer for Radiologists and Potential Complications

The availability of effective immunosuppressive medication is primarily responsible for the dramatic improvement in long-term graft survival rates after solid organ transplantation. The commonly used drugs include monoclonal/polyclonal antibodies, corticosteroids, calcineurin inhibitors (cyclosporine and tacrolimus), antimetabolites, mammalian target of rapamycin, and many novel drugs. Prolonged immunosuppression is accompanied by several well-described potentially life-threatening complications. In addition to drug-related side effects, recipients of solid organs are unavoidably at a higher risk for infections and malignancies. Select infections and malignancies in solid organ transplant patients have distinctive imaging findings, and radiologists play a crucial role in the timely diagnosis and management of these conditions.

Outcomes in organ transplants from donors with melanoma: a systematic review

Melanoma transmitted through organ transplantation is an increasingly reported event. Immunosuppression increases the risk of melanoma; however, transmission of malignancy from transplanted organs is a distinct etiology of melanoma occurrence. The risk of transmission of melanoma from an organ donor with melanoma has yet to be determined. The authors aimed to investigate this phenomenon by reviewing the outcomes of patients that received organs from donors with melanoma. A systematic literature review was conducted with emphasis on identifying organ donors with known histories of melanoma and reported information regarding recipients of their organs. The databases PubMed, MEDLINE, Embase, and JBI EBP were searched in January 2023. Search terms included "melanoma," terms for solid organs, "donor," "transplant," "transmission," and their variations as well as terms related to temporal relations. Inclusion criteria were articles that stated outcomes in organ recipients from donors that had a diagnosis of melanoma either pretransplant or postmortem. Reference lists of selected articles were hand searched for further studies. A total of 232 articles were identified from the search parameters. After applying inclusion and exclusion criteria, 13 articles were selected. Hand searching the references of these articles yielded four additional articles. Of the 75 organ recipients that received organs from donors with known melanoma, 43 developed melanoma. While a definitive quantitative risk cannot be ascertained based on our review, the numerous reported cases of melanoma in organ recipients from donors that have melanoma should still be considered by clinicians.

Imaging of Hepatobiliary Cancer

The liver and biliary tree are common sites of primary and secondary malignancies. MRI followed by CT is the mainstay for the imaging characterization of these malignancies with the dynamically acquired contrast enhanced phases being the most important for diagnosis. The liver imaging reporting and data system classification provides a useful framework for reporting lesions in patents with underlying cirrhosis or who are at high risk for developing hepatocellular carcinoma. Detection of metastases is improved with the use of liver specific MRI contrast agents and diffusion weighted sequences. Aside from hepatocellular carcinoma, which is often diagnosed noninvasively, other primary hepatobiliary tumors may require biopsy for definite diagnosis, especially when presenting with nonclassic imaging findings. In this review, we examine the imaging findings of common and less common hepatobiliary tumors.

Listing Dilemmas: Age, Frailty, Weight, Preexisting Cancers, and Systemic Diseases

Selection of lung transplant candidates is an evolving field that pushes the boundaries of what is considered the norm. Given the continually changing demographics of the typical lung transplant recipient as well as the growing list of risk factors that predispose patients to poor posttransplant outcomes, we explore the dilemmas in lung transplant candidate selections pertaining to older age, frailty, low and high body mass index, preexisting cancers, and systemic autoimmune rheumatic diseases.

Kaposi Sarcoma in a Child after Fanconi Anemia-Induced Haploidentical Hematopoietic Stem Cell Transplant: A Case Report

Kaposi sarcoma is relatively common after solid organ transplantation, but very rare after hematopoietic stem cell transplant (HSCT). Here we are reporting a rare case of Kaposi sarcoma in a child after HSCT. An 11-year-old boy with Fanconi anemia was treated by haploidentical HSCT from his father. Three weeks after transplantation, the patient developed severe graft-versus-host disease (GVHD) which was treated by immunosuppressive therapy and extracorporeal photopheresis. Approximately 6.5 months after HSCT, the patient had asymptomatic nodular skin lesions over the scalp, chest, and face. Histopathological examination showed typical findings of Kaposi sarcoma. Later, additional lesions in the liver and oral cavity were confirmed. Liver biopsy was positive for HHV-8 antibodies. The patient was continued on Sirolimus which was already being used for the treatment of GVHD. Cutaneous lesions were also treated with topical timolol 0.5% ophthalmic solution. Within six months, cutaneous and mucous membrane lesions were completely resolved. Follow-up abdominal ultrasound and MRI showed the disappearance of the hepatic lesion.

Multimodality imaging findings of infection-induced tumors

Several infections can predispose to certain malignancies in different body parts. These infections include viral, bacterial, and fungal pathogens. Imaging plays a vital role in the diagnosis, staging, and management of these neoplastic conditions. Furthermore, it can help in differentiating infection-related non-neoplastic processes that can mimic malignancies. Both radiologists and clinicians should be familiar with these conditions. This review discusses the epidemiology, pathogenesis, and imaging features of infection-related tumors.

Multimodality Imaging after Liver Transplant: Top 10 Important Complications

Patients who have undergone liver transplant are now regularly seen in day-to-day radiology practice. All surgical techniques for liver transplant require arterial, portal venous, hepatic venous and caval, and biliary anastomoses. This review is focused on the 10 "not to be missed" complications of liver transplant that affect the health and life of the graft and graft recipient. Arterial complications are the most common and devastating. Early hepatic artery thrombosis may be catastrophic because the biliary tree is solely dependent on the hepatic artery after transplant and collateral vessels have not yet formed. In contrast, delayed hepatic artery thrombosis may be more insidious as collateral arteries develop. US findings of delayed hepatic artery thrombosis may be similar to those of hepatic artery stenosis and celiac artery stenosis. Splenic artery steal syndrome is an increasingly recognized cause of graft ischemia. Venous complications are much less common. Hepatic venous and caval complications are notable for their increased incidence in living-donor and pediatric transplants. Biliary complications often result from arterial ischemia. Biliary cast syndrome is a notable example in which ischemic biliary mucosa sloughs into and obstructs the duct lumens. Neoplasms also may occur within the hepatic graft and may be due to recurrent malignancy, posttransplant lymphoproliferative disorder, or metastases. US is the initial imaging modality of choice, particularly in the acute postoperative setting. Further evaluation with contrast-enhanced US, CT, or MRI; catheter angiography; endoscopic retrograde cholangiopancreatography; and/or nuclear medicine studies is performed as needed. An invited commentary by Bhargava is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

Malignancies after pediatric solid organ transplantation

As life expectancy among pediatric solid organ transplant recipients (SOTRs) improves, the risk of comorbid conditions such as malignancy post-transplantation has also increased. SOTRs are at elevated risks of post-transplantation lymphoproliferative disorders (PTLDs), and skin and solid cancers. PTLDs typically occur early following transplantation, while skin and solid cancers frequently arise in young adulthood (25-40 years). By 30 years following transplantation, 26-41% of pediatric SOTRs have developed cancer. Different risk factors exist for PTLD, and skin and solid cancers, which are modified by cumulative immunosuppression, infections, transplanted organ, and the underlying disease process associated with initial organ failure (e.g., kidney failure). Optimal cancer treatment strategies depend on the specific cancer type, stage, and patient comorbidities. Immunosuppression reduction may be beneficial for certain cancers but must be considered against the risks of acute and chronic rejection and allograft loss. Lifestyle counseling regarding smoking avoidance and sun protection, as well as human papillomavirus vaccination, is an important aspect of cancer prevention. Currently, no cancer screening guidelines exist specifically for pediatric SOTRs. Adult population screening guidelines have not been validated in transplant populations. Therefore, an individualized approach should be taken to cancer screening for pediatric SOTRs, accounting for other cancer risk factors.

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.

Selection Criteria for Lung Transplantation: Controversies and New Developments

Lung transplantation is an accepted therapeutic option for end-stage lung diseases. The imbalance between limited availability and vast need of donor organs necessitates careful selection of recipient candidates, ensuring the best possible utilization of the scarce resource of organs. Nonetheless, possible lung transplant candidates who could experience a meaningful improvement in survival and quality of life should not be excluded solely based on the complexity of their case. In this review, controversial issues or difficult limitations for lung transplantation, and new developments in recipient selection criteria, are discussed, which may help broaden recipient eligibility for lung transplantation without compromising long-term outcomes.

Infiltrating Kaposi sarcoma presenting as acute kidney injury: An unexpected consequence of deliberate hepatitis C-positive organ transplantation

Kaposi sarcoma (KS) following kidney transplantation can result from recipient reactivation of latent human herpesvirus 8 (HHV-8) infection or activation of donor-acquired HHV-8 infection. Post-transplant KS typically manifests with cutaneous pathology, but rare cases of renal allograft involvement have been reported. We describe two cases of donor-derived HHV-8 infection in two hepatitis C (HCV) viremia-negative transplant recipients who each received a kidney from a donor with HCV viremia. One recipient did not develop KS while the other presented with acute kidney injury caused by extensive KS infiltration of the renal parenchyma and metastatic disease. This report reviews the literature for cases of KS involving the renal allograft and highlights an unexpected consequence of deliberate HCV-positive organ transplantation.

Pulmonary involvement in acquired immunodeficiency syndrome-associated Kaposi's sarcoma: a descriptive analysis of thin-section manifestations in 29 patients

Background

Acquired immunodeficiency syndrome-associated Kaposi's sarcoma (AIDS-KS) was the first malignant neoplasm to be described as being related to AIDS. The lungs are the most common visceral site of AIDS-KS. This study aimed to analyze the computed tomography (CT) manifestations of pulmonary involvement in AIDS-KS.

Methods

Twenty-nine male patients were enrolled in this retrospective study. Imaging evaluation parameters included lesion distribution, the flame sign, interlobular septal thickening, peribronchovascular interstitium thickening, ground-glass opacity (GGO), dilated blood vessels in lesions, and pleural effusion.

Results

A peribronchovascular distribution was observed in all patients, predominantly in the lower lobes. Of the patients, 58.62% (17/29) exhibited the flame sign, 75.86% (22/29) had interlobular septal thickening, 72.41% (21/29) had peribronchovascular interstitium thickening, 82.76% (24/29) had GGO, and 34.48% (10/29) had pleural effusion. Enlarged lymph nodes with a short-axis diameter >1.0 cm were found in 41.38% (12/29) of the patients. Of the 12 patients who underwent contrast-enhanced CT (CECT), 90.91% (11/12) had dilated blood vessels, and nodules, consolidations, and lymph nodes were observed to be strongly enhanced. Intrapulmonary lesions decreased in size or number after appropriate treatment during follow-up.

Conclusions

Common CT manifestations of pulmonary AIDS-KS include the flame sign, peribronchovascular distribution, peribronchovascular interstitium thickening, interlobular septa thickening, GGO, dilated blood vessel, and strong enhancement of nodules, consolidations, and lymph nodes. It is helpful to follow up the therapeutic effect of pulmonary AIDS-KS by chest CT.

The Challenging Management of Cancer: An Immunonephrologist's Perspective

INTRODUCTION

Onconephrology is an emerging medical subspecialization that focuses on the numberless interrelations between cancer and kidney diseases. Tumor cells evade immune surveillance through activation of immune checkpoint pathways that suppress antitumor immune responses. By blocking checkpoints, new anticancer agents disrupt immune homeostasis but potentially induce immune-mediated diseases. Nephrologists and nephroimmunologists should be able to treat the nephrotoxic sequelae of cancer therapy and ensure continuation of the life-saving treatment.

METHODS

Thirty-seven renal biopsies have been carried out over 42 months in oncologic patients, that is, 5.2% of the total native renal biopsies were carried out in the same period. The commonest diagnoses (>6 cases) were interstitial tubular nephritis, membranous glomerulopathy, IgA nephropathy, vasculitis, and focal and segmental glomerulosclerosis.

CASE PRESENTATION

Three example cases, including focusing on key questions which could involve the nephrologists are reported in detail. They include a cancer-related Goodpasture Syndrome, the peculiar toxic effects of pemetrexed on tubular cells, and the intriguing relationship between bevacizumab and cryoglobulinemic glomerulonephritis.

CONCLUSION

As shown by these 3 example cases, nephrologists need to be open-minded with regard to kidney biopsy in order to get a timely diagnosis. Nephrologists also need to improve their knowledge of cancer biology and therapy in order to prevent kidney problems, manage therapy-related immune-mediated disorders, and improve patient life expectancy.

Post-renal transplant malignancies: Opportunities for prevention and early screening

GOAL OF THE REVIEW

While transplant recipients are aware of increased malignancy risk, there is little consensus on the preventative measures. The goal of this review is to bring available preventative measures to light and prompt more research to be done with ultimate goal of developing an individualized prevention plan for each patient based on risk factors and available screening tools.

INTRODUCTION

Transplant surgery offers patients with end-stage renal disease a longer life expectancy with help of immunosuppressive therapies. Nonetheless, life-long immunosuppression comes at a cost of post-renal transplant malignancies, which have become the leading cause of morbidity in this patient group.

DISCUSSION

Post-renal transplant cancers can develop through either de novo, by donor-related transmission, or recurrence of recipient's pre-transplant cancer. While immunosuppressive therapy is considered to be the leading cause, weakened immunosurveillance of neoplastic cells and inadequate immune response against oncogenic viruses also plays an important role. The most common cancers seen in renal transplant patients are skin cancers and post-transplant lymphoproliferative disorder (PTLD). Risk factors for skin cancers have are ultraviolet light, human papilloma virus infection, and use of cyclosporin and azathioprine. Numerous viral infections have been associated with transplant-related malignancies post-transplant.

CONCLUSION

While lowering of immunosuppressive therapy remains the treatment of choice, it may lead to graft failure. Given some of the presented malignancies have modifiable risk factors and options for screening, clinical outcomes can be improved. Limiting skin exposure, dermatologic screening, and prophylactic retinoids can help lower the incidence rate of skin malignancy. Endoscopic screening for renal transplant patients can help identify gastric adenocarcinoma early and improve survival rates. Some of the post-transplant malignancies have been responsive to anti-viral treatment.

Association between infectious event and de novo malignancy after heart transplantation

The aim of the study was to investigate the incidence of and risk factors for de novo malignancy after heart transplantation (HTx) in a single center. We assessed 102 consecutive patients who received HTx and were followed-up in our center regularly for > 1 year from June 2006 to May 2018. We investigated the incidence of and risk factors for de novo malignancy. The cumulative incidence of each malignancy type during the follow-up period was one (0.98%) for skin cancer, four (3.92%) for nonskin solid organ cancer, and six (5.88%) for posttransplant lymphoproliferative disorder (PTLD). The percentage of patients with more than one infectious event ≤ 1 year after HTx was higher in the malignancy group than in the non-malignancy group. Furthermore, Kaplan-Meier analysis revealed that the incidence rate of infectious events was higher in patients with malignancies than in those without (log-rank P < 0.001). After dividing malignancies into a PTLD group and a solid organ malignancy group, we found that negative Epstein-Barr virus serostatus, cytomegalovirus-positive antigenemia, and the occurrence of any viral or gastrointestinal infectious event at ≤ 1 year were more frequent in patients with PTLD than in patients without it. The survival rate was significantly lower for patients with solid organ malignancy than for patients without malignancy. In conclusion, there was a correlation between infectious events and de novo malignancy, particularly in patients with PTLD. We should confirm this finding by conducting a larger cohort study.

Multimodality imaging of pancreas-kidney transplants

Simultaneous pancreas-kidney transplant remains a treatment option for patients with insulin-dependent diabetes mellitus type 1, aimed at restoring normoglycemia, alleviating insulin dependency, avoiding diabetic nephropathy, and thereby improving the quality of life. Imaging remains critical in the assessment of these transplant grafts. Ultrasound with Doppler remains the primary imaging modality for establishing baseline assessment of the graft as well as for evaluating vascular, parenchymal, and perigraft complications. Noncontrast MR imaging is preferred over non-contrast CT for evaluation of parenchymal or perigraft complications in patients with decreased renal function, although contrast-enhanced CT/MR imaging may be obtained following multidisciplinary consultation in cases with high clinical and laboratory suspicion for graft dysfunction. Catheter angiography is reserved primarily for therapeutic intervention in suspected or confirmed vascular complications. An understanding of the surgical techniques and imaging appearance of a normal graft is crucial to identify potential complications and direct timely management. This article provides an overview of surgical techniques, normal imaging appearance, as well as the spectrum of imaging findings and potential complications in pancreas-kidney transplants.

Clinical Significance of De Novo Malignancy After Liver Transplant: A Single-Center Study

BACKGROUND

Several studies have reported that solid organ transplant recipients have a high risk for malignant tumors because the suppressed immune system fails in preventing malignant transformations. De novo malignancy after transplantation is the most common cause of death in the late period after liver transplant (LT). This study investigated the clinical significance of de novo malignancy after LT, and it is the largest study based in Korea to report long-term follow-up results associated with de novo malignancy after LT.

METHODS

Data of 1793 adults who underwent LT in Seoul National University Hospital were retrospectively collected, and medical charts and data from the Ministry of Public Administration and Security were reviewed to examine the causes of death and de novo malignancy status. The Fisher exact test and Kaplan-Meier survival analysis were used to analyze the data.

RESULTS

Of the 1793 recipients, 27 died of de novo malignancies. Of 875 hepatocellular carcinoma (HCC) patients, 12 died, and of 918 non-HCC patients, 15 died. De novo malignancy was the main cause of death at 5 years after LT but was not in the initial 5 years. In Korea the most common cancers that developed after LT were gastric cancer (21.4%) and lymphoma (14.3%). De novo HCC in non-HCC cases was found in 2 patients.

CONCLUSION

De novo malignancy is a key factor affecting long-term survival after LT. Therefore, regular screening and education are important for improving long-term survival and quality of life in these patients after LT.

Imaging of Renal Transplant Complications throughout the Life of the Allograft: Comprehensive Multimodality Review

The kidney is the most commonly transplanted solid organ. Advances in surgical techniques, immunosuppression regimens, surveillance imaging, and histopathologic diagnosis of rejection have allowed prolonged graft survival times. However, the demand for kidneys continues to outgrow the available supply, and there are efforts to increase use of donor kidneys with moderate- or high-risk profiles. This highlights the importance of evaluating the renal transplant patient in the context of both donor and recipient risk factors. Radiologists play an integral role within the multidisciplinary team in care of the transplant patient at every stage of the transplant process. In the immediate postoperative period, duplex US is the modality of choice for evaluating the renal allograft. It is useful for establishing a baseline examination for comparison at future surveillance imaging. In the setting of allograft dysfunction, advanced imaging techniques including MRI or contrast-enhanced US may be useful for providing a more specific diagnosis and excluding nonrejection causes of renal dysfunction. When a pathologic diagnosis is deemed necessary to guide therapy, US-guided biopsy is a relatively low-risk, safe procedure. The range of complications of renal transplantation can be organized temporally in relation to the time since surgery and/or according to disease categories, including immunologic (rejection), surgical or iatrogenic, vascular, urinary, infectious, and neoplastic complications. The unique heterotopic location of the renal allograft in the iliac fossa predisposes it to a specific set of complications. As imaging features of infection or malignancy may be nonspecific, awareness of the patient's risk profile and time since transplantation can be used to assign the probability of a certain diagnosis and thus guide more specific diagnostic workup. It is critical to understand variations in vascular anatomy, surgical technique, and independent donor and recipient risk factors to make an accurate diagnosis and initiate appropriate treatment.^©RSNA, 2019.

Malignancy after lung transplantation

Lung transplantation is an established therapeutic option for selected patients with advanced lung diseases. As early outcomes after lung transplantation have improved, chronic medical illnesses have emerged as significant obstacles to long-term survival. Among them is post-transplant malignancy, currently representing the 2^nd most common cause of death 5–10 years after transplantation. Chronic immunosuppressive therapy and resulting impairment of anti-tumor immune surveillance is thought to have a central role in cancer development after solid organ transplantation (SOT). Lung transplant recipients receive more immunosuppression than other SOT populations, likely contributing to even higher risk of cancer among this group. The most common cancers in lung transplant recipients are non-melanoma skin cancers, followed by lung cancer and post-transplant lymphoproliferative disorder (PTLD). The purpose of this review is to outline the common malignancies following lung transplant, their risk factors, prognosis and current means for both prevention and treatment.

A Review of Viral-Related Malignancies and the Associated Imaging Findings

OBJECTIVE. Imaging plays an important role in the diagnosis and staging of malignancies. Many common lymphoproliferative and other solid tumor malignancies can be viral-related. CONCLUSION. This review discusses the imaging findings that can be associated with common viral-induced malignancies. Knowledge of these imaging presentations can help narrow the differential diagnosis to reach a specific diagnosis through a precise workup and proper management.

Immunosuppression following organ transplantation. Part 2: complications and their management

Advances in the care of patients who have had a solid organ transplant has led to a growing population of post-transplant patients, who are also living for longer. As a result of their longer life expectancy, transplant recipients often face a multitude of challenges, including optimising their immunosuppressive regimens and managing potential complications. Life-threatening infections, malignancies, and organ-specific toxicities are the complications post-transplant patients commonly encounter and these complications are often associated with increased morbidity and mortality, adverse graft functioning and survival, profound impairment in the patient's quality of life, and significant healthcare burden. This article, the second of two parts, gives an overview of the issues involved in the care of patients who are receiving immunosuppressants. The common complications encountered by post-transplant patients are discussed and their assessment, management, prevention and treatment explored.

Preventive Role of mTOR Inhibitor in Post-Kidney Transplant Urothelial Carcinoma

BACKGROUND

There is little evidence about whether mammalian target of rapamycin (mTOR) inhibitor could prevent post-kidney transplant (KT) urothelial carcinoma (UC) or not. The aim of this study is to analyze the role of mTOR inhibitor add-on in tacrolimus-based kidney transplant recipients.

METHOD

The data were obtained from the Kaohsiung Chang Gung Memorial Hospital using the Chang Gung Research Database and retrospectively reviewed from January 2000 to December 2015. Patients then were categorized into 2 groups: group FK (more than 2-year tacrolimus [FK] prescription) and group FK + mTOR inhibitor (more than 2-year tacrolimus plus at least 6-month continued sirolimus prescription). The primary end point is post-KT UC development. The secondary end point is mTOR inhibitor add-on effect on renal function deterioration episode.

RESULTS

There were 140 patients with tacrolimus-based immunosuppressant (group FK) and 82 patients with tacrolimus-based and add-on mTOR inhibitor regimen (group FK + mTOR inhibitor). The follow-up duration, sex distribution, and combined mycophenolate mofetil rate are similar in both groups. Younger age, lower tacrolimus trough level, lower UC incidence, and longer KT-to-UC interval were observed. Short- to intermediate-term results revealed noninferior graft outcome by creatinine level or creatinine deterioration.

CONCLUSIONS

In our preliminary result, mTOR inhibitor add-on in patients with tacrolimus-based regimen revealed less post-KT UC occurrence. In addition, noninferior graft outcome was also observed. In Taiwan, a high UC prevalence area, mTOR inhibitor add-on strategy can be considered as a preventive strategy for UC after KT.

Identity determination in diagnostic surgical pathology

From a technical perspective, specimen identity determination in surgical pathology over the last several decades has primarily focused on analysis of repetitive DNA sequences, specifically microsatellite repeats. However, a number of techniques have recently been developed that have similar, if not greater, utility in surgical pathology, most notably analysis of single nucleotide polymorphism (SNPs) and gene panels by next generation sequencing (NGS). For cases with an extremely limited sample or a degraded sample, sequence analysis of mitochondrial DNA continues to be the method of choice. From a diagnostic perspective, interest in identity determination in surgical pathology is usually centered on resolving issues of specimen provenance due to specimen labeling/accessioning deficiencies and possible contamination, but is also frequently performed in cases for which the patient's clinical course following definitive therapy is remarkably atypical, in cases of an unexpected diagnosis, and by patient request for "peace of mind". However, the methods used for identity determination have a much broader range of applications in surgical pathology beyond tissue provenance analysis. The methods can be used to provide ancillary information for cases in which the histomorphology is not definitively diagnostic, as for example for tumors that have a virtually identical microscopic appearance but for which the differential diagnosis includes synchronous/metachronous tumors versus a metastasis, and for the diagnosis of hydropic early gestations versus hydatidiform molar pregnancies. The methods also have utility in several other clinical settings, for example to rule out a donor-transmitted malignancy in a transplant recipient, to monitor bone marrow transplant engraftment, and to evaluate natural chimerism.

Integrated Proteome and Cytokine Profiles Reveal Ceruloplasmin Eliciting Liver Allograft Tolerance via Antioxidant Cascades

Acute rejection (AR) and spontaneous tolerance may occur after allograft orthotopic liver transplants (OLT) performed in certain combinations of donor and recipient rat strains, yet the underlying molecular cascades involved in these conditions remain poorly understood. Comprehensive analysis with proteomic tools revealed that ceruloplasmin was highly expressed during the tolerant period on day 63 post-OLT (POD 63) compared to the rejected samples on POD 14. Meanwhile, cytokine expression profiles implied that the inflammation was significantly stimulated in the AR subjects. Again, protein carbonylation was dramatically upregulated in the rejected subject within the tolerant group. Knockdown of ceruloplasmin would elicit more severe ROS damage, leading to cell death in the presence of H₂O₂, which induced Nrf2 cascade and the recovery of ceruloplasmin to mediate spontaneous tolerance. In summary, ceruloplasmin may contribute to amending the oxidative stress that eventually causes cell apoptosis and to maintaining the survival of hepatocytes in a drug-free tolerance OLT model.

Immune-checkpoint inhibitors to treat cancers in specific immunocompromised populations: a critical review

INTRODUCTION

Because of their efficacy against numerous cancers, immune-checkpoint inhibitors (ICIs), anti-cytotoxic T-lymphocyte antigen-4, and anti-programmed cell death monoclonal antibodies are being used ever more often in oncology. However, some patients were excluded from clinical trials because of their comorbidities despite their potentially higher cancer frequencies, as is the case for immunocompromised patients. Areas covered: We analyzed reported preclinical and clinical information and evaluated the risk/benefit ratio for four immunocompromised populations: people living with human immunodeficiency virus (PLHs), solid-organ transplant recipients, recipients of hematopoietic stem-cell allografts, and patients with autoimmune diseases. Expert commentary: Information available in the literature is fragmentary and scarce, making it difficult to evaluate the risk/benefit ratio. It can, nonetheless, be noted that ICI use in PLHs seems possible. For solid-organ transplant recipients, the risk for the graft seems elevated. For the other two populations, it is difficult to conclude at this time.

Post-transplant malignancies in pediatric liver transplant recipients: Experience of two centers in Turkey

BACKGROUND/AIMS

A liver transplant is the preferred treatment for patients with end-stage liver disease, as it usually results in longterm survival. However, due to the use of chronic immunosuppressive therapy, which is necessary to prevent rejection, de novo cancer is a major risk after transplantation. The aim of this study was to assess the incidence of post-transplant malignancies in children after liver transplantations.

MATERIALS AND METHODS

The study group consisted of 206 liver transplant recipients, with no history of cancer, including hepatocellular carcinoma, in two liver transplantation centers in Turkey between 1997 and 2015. Data were obtained from patient's data chart.

RESULTS

In the study group, de novo cancer was diagnosed in 13 of the 206 patients. Post-transplant lymphoproliferative disease (PTLD) occurred in seven (53.8%) patients and other malignancies in six of the 13 patients. The types of PTLD were as follows: B-cell origin (n=2), Epstein-Barr virus (EBV)-related (n=2), T-cell origin (n=1), and Hodgkin's lymphoma (n=2). EBV DNA was isolated from seven patients, three of whom developed PTLD. The others developed Kaposi's sarcomas, Burkitt's lymphomas, cutaneous large-cell lymphomas, Hodgkin's lymphomas, and liver sarcomas.

CONCLUSION

After transplantation, immunosuppressive treatment is unavoidable, increasing the risk of malignancies. However, a close follow-up and periodic screening can reduce cancer-related mortality and morbidity.