New Developments in the Diagnosis and Management of Posttransplantation Lymphoproliferative Disorders in Solid Organ Transplant Recipients

Global research productivity of post-transplant lymphoproliferative disorder: a bibliometric study

Background

Post-transplant lymphoproliferative diseases (PTLD) are a heterogeneous collection of neoplasms that occur after solid organ transplants (SOT). In the past 20 years, there has been a rise in PTLD research. This study aims to investigate the global research output and interest regarding PTLD using a bibliometric approach.

Material and methods

On 28 November 2022, the Web of Science Core Collection documents on PTLD published between 2000 and 2022 were collected and analyzed using bibliometric techniques. The VOSviewer application was utilized to visualize the annual number of publications, authors, organizations, countries, published journals, citations, and most occurring keywords.

Results

A total of 2814 documents were retrieved, and a screening process included 1809 documents. The total number of citations was 45 239, and the average number per item was 25. Most articles (n = 747) and citations (n = 25 740) were produced in the United States. Based on citations, most of the top 10 institutions that contributed were in the United States of America. The University of Pittsburgh topped the list with 2700 citations and 64 articles. The vast majority of articles were published in Pediatric Transplantation (n = 147), Transplantation (n = 124), and the American Journal of Transplantation (n = 98). Transplantation has received the most citations, 6499, followed by the American Journal of Transplantation with 5958 citations and Blood with 4107 citations.

Conclusion

With ongoing debates over optimal classification, Epstein-Bar virus involvement, and treatment, this topic has received significant interest from researchers in recent years. Our results can be used as a guide for future research in the field and as a framework for a more in-depth look at the scientific progress of PTLD.

Complete Recovery After Immunosuppressive Treatment Change in a Patient With Posttransplant Lymphoproliferative Disorder

Posttransplant lymphoproliferative diseases are a rare but important cause of morbidity and mortality secondary to immunosuppression after solid-organ or bone marrow transplant. Generally, posttransplant lymphoproliferative diseases develop in the first 2 years after transplant, when immunosuppressive therapy is the most intense. Change or reduction in immunosup - pressive treatment is an option for treatment of posttransplant lymphoproliferative diseases. We evaluated the treatment of a patient with posttransplant lymphoproliferative disease after liver transplant. A 64-year-old man underwent liver transplant from a living donor (the patient's son) in 2011 to treat hepatocellular cancer secondary to chronic hepatitis B. Tacrolimus and mycophenolate mofetil were used for immunosuppression through 9 years after liver transplant. In the abdominal computed tomography performed in response to abdominal pain during follow-up in March 2019, multiple solid lesions were observed. A liver biopsy revealed posttransplant lymphoproliferative disease with diffuse large B-cell lymphoma. Fluorine-18 positron emission tomography/computed tomography imaging of the patient showed no pathology in favor of primary lymphoproliferative disease. Mycophenolate mofetil and tacrolimus treatment was changed to everolimus. In the follow-up dynamic magnetic resonance imaging examination that was performed at 3 months after treatment change, we observed that the lesion at liver segment 6 had regressed to 30 mm and several lesions with similar features were observed in the right lobe of the liver. Additional liver biopsy results were compatible with complete remission. The patient's clinical symptoms had fully regressed at 18 months after the diagnosis of PTLD, at the time of this writing. Ongoing radiological and clinical follow-up has shown complete remission. Change from calcineurin treatment to treatment with an inhibitor of the mechanistic target of rapamycin may be an essential and new option for treatment of posttransplant lymphoproliferative disease after liver transplant.

Safety and tolerability of a 90-minute rapid infusion of Sandoz biosimilar rituximab in B-cell lymphoproliferative disorders in a real-world setting

Although rituximab is generally well-tolerated, infusion-related reactions (IRRs) are common with the initial dose when administered intravenously according to standard recommendations. To prevent IRRs, premedication and low-speed infusion rates have been recommended. Consequently, intravenous (i.v.) infusion of rituximab can become a labor-intensive process. Rapid i.v. rituximab infusion over 90 min has demonstrated a favorable safety profile for the second and subsequent infusions during the course of therapy. The aim of this study was to investigate the safety and tolerability of 90-min rapid infusion of Sandoz rituximab biosimilar (SDZ-RTX) for patients with CD20+ lymphoma or chronic lymphocytic leukemia (CLL). We retrospectively reviewed all patients with CD20+ lymphoma or CLL who received SDZ-RTX infusions in 90 min from July 2019 to July 2021 at seven Spanish hospitals. The primary end point was the incidence of IRRs. We identified 124 patients and 576 rapid administrations of SDZ-RTX, with an average of five rapid infusions per patient. Most rapid infusions of SDZ-RTX were in combination with CHOP/CHOP-like therapy (48.4%), followed by SDZ-RTX alone (15.1%), in combination with bendamustine (14.5%), or with other regimens (22%). The 90-min SDZ-RTX infusion schedule was well-tolerated with no grade 3/4 IRRs. The incidence of any grade IRR during the first rapid infusion was 1% (5 grade 1 IRRs and 1 grade 2 IRR). In conclusion, rapid 90-min i.v. administration of SDZ-RTX for the second and subsequent infusions during the course of therapy is well-tolerated in patients with CD20+ lymphoma or CLL.

Management of Epstein-Barr Virus Infection and Post-Transplant Lymphoproliferative Disorder in Pediatric Liver Transplantation

With the advancement of immunosuppressive strategies, the outcome of liver transplantation during childhood has dramatically improved. On the other hand, Epstein–Barr virus (EBV) infection and associated post-transplant lymphoproliferative diseases (PTLD), such as malignant lymphoma, are serious complications that contribute to morbidity and mortality, and are still an important issue today. Recently, an early diagnosis by quantitative PCR and PET-CT testing, and treatment with rituximab (an anti-CD20 antibody) has been established, and long-term remission has been achieved in many cases. However, the optimal immunosuppression protocol after remission of PTLD needs to be determined, and it is hoped that a treatment for refractory PTLD (e.g., PTL-NOS) will be proposed.

Unusual presentation of extranodal diffuse large B-cell lymphoma in a solid-organ recipient during long-term immunosuppressive treatment

INTRODUCTION

Posttransplant lymphoproliferative disorders (PTLDs) refer to a group of diseases, including diffuse large B-cell lymphoma (DLBCL), that develop after solid organ transplantation or hematopoietic stem cell transplantation. Extranodal involvement in PTLDs is common. Reports about exclusive bone marrow involvement are rare.

CASE DESCRIPTION

A 70-year-old woman, who had undergone kidney transplantation in 2018, was diagnosed with exclusively extranodal, Epstein-Barr virus-negative DLBCL, with bone marrow and spleen involvement, during long-term immunosuppression. She achieved complete remission with combined immunochemotherapy and temporary hold of immunosuppression.

CONCLUSIONS

This case shows an uncommon clinical presentation of DLBCL, which was challenging to diagnose, being entirely extranodal. The favorable clinical course relied on timely diagnosis and a multidisciplinary approach. Long-term consequences of posttransplant immunosuppression require a high level of suspicion for an appropriate management, aimed at preserving the graft while eradicating the lymphoproliferative disorder.

Posttransplant Lymphoproliferative Disorder After Solid Organ Transplant: A Heterogeneous, Aggressive Disorder

Posttransplant lymphoproliferative disorder (PTLD) is a rare complication of solid organ transplant. We identified 40 patients diagnosed with PTLD between 2009 and 2020 and analyzed their presentation, treatment strategies, and outcomes. Median age at diagnosis was 52.5 years (range 21.3 to 79). Median duration of immunosuppression was 95 months (range 4 to 292). Diffuse large B cell lymphoma (n = 16, 40%) and Burkitt lymphoma (n = 6, 15%) were the most common histological subtypes. First-line therapy varied. The median number of treatment lines was 1 (range 0 to 4). Sixteen patients (40%) achieved complete response after first-line therapy. Nineteen patients (47.5%) relapsed or progressed and received salvage therapy; 45% were alive at the end of the study period (median survival 52 months; range 1 to 266; 95% confidence interval 0 to 104). Causes of death included lymphoma-related (45.5%), therapy-related (27.3%), and other (27.3%). Five (22.7%) died within 3 months of diagnosis. Pearson's r test identified disease stage (P = .045) and proliferation index (P = .005) as negative predictors of response to frontline therapy. Bone marrow involvement (P = .033) and increased age (P = .018) were significant predictors of survival. Early mortality and poor response to frontline therapy are common, outlining the need for improved treatment strategies.

A multicenter survey on post-transplant lymphoproliferative disorders in pediatric heart transplant recipients: A case for development of consensus guidelines for screening, surveillance, and treatment?

Post-transplant lymphoproliferative disorders (PTLD) are the main malignancy seen after pediatric heart transplant and are a significant cause of morbidity and mortality. Prior to the development of detailed guidelines, we sought to identify trends in screening, diagnosis, and treatment of pediatric PTLD. All Pediatric Heart Transplant Society (PHTS) institutions were surveyed. No identifiable patient information was shared. From 56 PHTS centers, 22 responses were received (39.3%). 100% agree PTLD cannot be diagnosed solely based on elevated Epstein-Barr virus (EBV) load. All respondents routinely screen for EBV by blood PCR, but frequency of screening varies. There was intermediate consensus regarding the use of computed tomography (CT) and/or positron emission tomography (PET) in surveillance management for PTLD. Most centers require a diagnostic biopsy before initiating new treatment for PTLD (14 of 18, 77.8%), but many reduce immune suppression based on elevated EBV without pathologic PTLD (16 of 22, 72.7%). Beyond immune modulation, rituximab is most commonly used (9 of 13, 69.2%). Consultation with oncology is common (17 of 17, 100%), but timing varies widely. Our survey highlights significant elements of agreement and significant practice variation among PHTS institutions regarding pediatric PTLD. Reduction of immune suppression prior to pathologic diagnosis of PTLD is a common management strategy. When this fails, rituximab is used, but is most often reserved until after confirmation of the diagnosis. Oncology subspecialists are commonly involved in these cases. Our findings highlight the need to develop improved guidelines for evaluation and treatment of pediatric PTLD.

Donor-derived Viral Infections in Liver Transplantation

Donor-derived infections are defined as any infection present in the donor that is transmitted to 1 or more recipients. Donor-derived infections can be categorized into 2 groups: "expected" and "unexpected" infections. Expected transmissions occur when the donor is known to have an infection, such as positive serology for cytomegalovirus, Epstein Barr virus, or hepatitis B core antibody, at the time of donation. Unexpected transmissions occur when a donor has no known infection before donation, but 1 or more transplant recipients develop an infection derived from the common donor. Unexpected infections are estimated to occur in far less than 1% of solid organ transplant recipients. We will review the epidemiology, risk factors, and approaches to prevention and management of donor-derived viral infectious disease transmission in liver transplantation.

Association of Epstein‑Barr virus infection with allogeneic hematopoietic stem cell transplantation in patients in Portugal

The identification of patients at higher risk of developing Epstein-Barr virus (EBV) infection in hematopoietic stem cell transplants (HSCT) is useful for the prevention of EBV-associated diseases A prospective observational study was developed that included 40 patients (27 male and 13 females, with mean age of 32.2±1.5 years old) undergoing allogeneic-HSCT between January and December 2015. EBV was examined in whole blood samples collected during routine procedures at day (D)+30, D +60, +90, D+120, D+150 and D+180 post-transplant. EBV was detected, at least once during the follow-up period in 70.0% of our patients. Results indicated that patients with unrelated donors had increased risk of developing EBV infection at D+60 and D+150 (OR=3.9, P=0.058; OR=8.0, P=0.043; respectively). Moreover, myeloablative conditioning (OR=4.3, P=0.052), anti-thymocyte globulin use (OR=12.0, P=0.030) and graft-vs.-host disease (OR=6.7, P=0.032) were associated with EBV infection at D+60, D+150 and D+90, respectively. In our series, none of these patients developed post-transplant lymphoproliferative disease. To the best of our knowledge, the present study is the first study to report EBV infection in patients undergoing aHSCT from Portugal. The study revealed that EBV infection is associated with different factors. These findings provide evidence towards the identification of high-risk patients for EBV-infection and associated disease.

[Infections in immunocompromised patients (II). The transplanted patient]

Los receptores de los diferentes tipos de trasplante presentan un riesgo elevado de infección. En los trasplantados de precursores hematopoyéticos predominan las infecciones nosocomiales. Durante el periodo posprendimiento temprano (30-100 días tras la infusión del trasplante), la incidencia de infección es más elevada en pacientes con enfermedad de injerto contra huésped. En el pulmón pueden aparecer lesiones nodulares por infección fúngica invasora o bien un patón difuso habitualmente secundario a infección vírica o a neumonía por P. jirovecii. Después de los primeros 100 días persiste un moderado riesgo de infección por microorganismos convencionales y oportunistas, como la infección tardía por CMV. Los avances en las técnicas quirúrgicas y el empleo de calcineurínicos han reducido la mortalidad por infecciones en trasplantados de órgano sólido. Durante el primer mes, son frecuentes las infecciones nosocomiales; entre el primer y sexto mes son más frecuentes las infecciones oportunistas dependientes de la inmunidad celular y a partir de sexto mes el riesgo baja y predominan las infecciones comunitarias semejantes a las de los pacientes inmunocompetentes.

Pediatric Liver Transplantation: An Update for the Pediatrician

Pediatric liver transplantation is a state-of-the-art treatment for children with end-stage liver disease. Over the past few decades, the advent of new surgical techniques using split liver grafts and living donors has drastically increased the organ availability for pediatric patients, while advances in immunosuppression have improved overall outcomes. The pediatrician is a key player in the multidisciplinary team that cares for these children starting with the timely referral of children who require liver transplantation to the active participation in optimizing the child's overall health before and after transplantation. [Pediatr Ann. 2016;45(12):e439-e445.].

Surgical Pathologic Diagnosis

Surgical pathology results can play a crucial role in the management of immunocompromised patients. Here we highlight factors that differ between immunocompromised and immunocompetent hosts, such as variation in inflammatory response. Conditions that are covered include drug reactions, disease within solid organ allografts, immune reconstitution inflammatory syndrome, specific immunodeficiency syndromes, neoplasms related to viral infections, and viral, bacterial, fungal, and parasitic infections. Special techniques including immunohistochemistry, in situ hybridization and molecular detection of pathogen nucleic acid from formalin-fixed, paraffin-embedded tissue are discussed.

Primary Epstein-Barr virus infection, seroconversion, and post-transplant lymphoproliferative disorder in seronegative renal allograft recipients: a prospective cohort study

BACKGROUND

Epstein-Barr virus (EBV)-seronegative renal transplant recipients are at risk of post-transplant lymphoproliferative disorder (PTLD). We compared primary EBV infection, seroconversion, and PTLD in EBV-seronegative patients who received renal allograft from seropositive or seronegative donors (D+/R- and D-/R-, respectively).

METHODS

We prospectively followed 25 D+/R- and 8 D-/R- recipients. We followed patients from January 1999 to June 2009 with clinical visits, monthly EBV polymerase chain reaction tests, and serologic tests for a period of 1 year after kidney transplantation and on an individual basis thereafter.

RESULTS

Three patients (9%) developed PTLD including 2 early-onset (<12 months) and 1 late-onset (>12 months) disease. In D+/R- and D-/R- patients, the frequencies of PTLD (8% vs. 12.5%, P = 0.7), EBV seroconversion (64% vs. 50%, P = 0.4), and EBV viremia (40% vs. 25%, P = 0.6) were not significantly different. Clinical, serologic, and virologic surveillance as well as reduction in immunosuppression after evidence of primary EBV infection resulted in a PTLD rate of 9%, despite a seroconversion rate of 60.6%. Rate of graft loss after reduction in immunosuppression was 10% (2 of 20), which was not significantly different from 13 patients without EBV seroconversion (no graft loss, P = 0.5). Rates of viremia, seroconversion, and PTLD in D+/R- and D-/R- patients appear to be similar.

CONCLUSIONS

The incidence of PTLD in renal transplants ranges from 0.5% to 2.9%. Our data show a significantly higher rate in EBV-seronegative renal allograft recipients, suggesting the need for close surveillance. Our data also suggest that donors for EBV-seronegative recipients may be accepted irrespective of positive or negative serostatus, with ongoing surveillance important in either circumstance.

Prompt diagnosis and management of Epstein-Barr virus-associated post-transplant lymphoproliferative disorder and hemophagocytosis: A dreaded complication in a post-liver transplant child

EBV-associated PTLD is increasingly recognized as an important cause of morbidity and mortality in both solid organ and hematopoietic stem cell transplant recipients. Mortality rates due to PTLD and virus-induced HLH are reported to be quite high. We report a case of EBV-associated PTLD and HLH in a child after liver transplantation who was successfully managed due to timely intervention. This case highlights that measurement of EBV load by quantitative polymerase chain reaction assays is an important aid in the surveillance and diagnosis of PTLD and early detection of EBV-induced PTLD, and aggressive treatment with rituximab is a key to survival in patients who have undergone liver transplantation.

Blood disorders typically associated with renal transplantation

Renal transplantation has become one of the most common surgical procedures performed to replace a diseased kidney with a healthy kidney from a donor. It can help patients with kidney failure live decades longer. However, renal transplantation also faces a risk of developing various blood disorders. The blood disorders typically associated with renal transplantation can be divided into two main categories: (1) Common disorders including post-transplant anemia (PTA), post-transplant lymphoproliferative disorder (PTLD), post-transplant erythrocytosis (PTE), and post-transplant cytopenias (PTC, leukopenia/neutropenia, thrombocytopenia, and pancytopenia); and (2) Uncommon but serious disorders including hemophagocytic syndrome (HPS), thrombotic microangiopathy (TMA), therapy-related myelodysplasia (t-MDS), and therapy-related acute myeloid leukemia (t-AML). Although many etiological factors involve the development of post-transplant blood disorders, immunosuppressive agents, and viral infections could be the two major contributors to most blood disorders and cause hematological abnormalities and immunodeficiency by suppressing hematopoietic function of bone marrow. Hematological abnormalities and immunodeficiency will result in severe clinical outcomes in renal transplant recipients. Understanding how blood disorders develop will help cure these life-threatening complications. A potential therapeutic strategy against post-transplant blood disorders should focus on tapering immunosuppression or replacing myelotoxic immunosuppressive drugs with lower toxic alternatives, recognizing and treating promptly the etiological virus, bacteria, or protozoan, restoring both hematopoietic function of bone marrow and normal blood counts, and improving kidney graft survival.

Evaluation of Epstein-Barr virus-specific immunologic response in solid organ transplant recipients with an enzyme-linked ImmunoSpot assay

Epstein-Barr virus (EBV) is a γ-herpes virus, responsible for infectious mononucleosis in immunocompetent hosts. Cellular immunity appears rapidly during EBV primary infection, keeping it silent despite long-life persistence in B lymphocytes. Defects of the EBV-specific cellular immunity are supposed to be the basis of post-transplantation lymphoproliferative disorders, promoted by high levels of immunosuppression. We retrospectively reviewed 197 solid organ transplant recipients to investigate EBV-specific lymphocyte responsiveness using Enzyme-linked ImmunoSpot assay (EliSpot), which assesses the EBV-specific interferon (IFN)-γ producing peripheral blood mononuclear cells, and kinetics of EBV infection/reactivation post-transplantation using quantitative real-time polymerase chain reaction (PCR) on whole blood. Overall, 102 of the 197 patients (51.8%) showed EBV responsiveness at the EBV-EliSpot assay: 68 (66.6%) showed a persistently positive EBV response in 3 or more determinations and 34 (33.3%) had transient episodes of nonresponsiveness. Ninety-five (48.2%) patients were persistently EBV nonresponders. EBV-DNAemia data were available for 58 patients: 27.6% presented at least one episode of EBV-DNA occurrence. No differences were found in EBV-EliSpot response stratification between the groups of patients who experienced episodes of EBV reactivation and those without EBV-DNAemia. However, EBV DNAemia peak values tended to be higher in the first year post-transplantation in the group of patients with a persistent positive EBV-specific immune response. EBV viral load quantitation in blood and EliSpot EBV-specific immune response determination may represent a powerful tool for monitoring solid organ transplant recipients, guiding immunosuppression modulation in patients with active EBV replication.

Duplex realtime PCR method for Epstein-Barr virus and human DNA quantification: its application for post-transplant lymphoproliferative disorders detection

INTRODUCTION

The quantification of circulating Epstein-Barr virus (EBV) DNA is used to monitor transplant patients as an early marker of Post-Transplant Lymphoproliferative Disorders (PTLD). So far no standardized methodology exists for such determination.

OBJECTIVE

Our purpose was to develop and validate a real-time PCR assay to quantify EBV DNA in clinical samples from transplant recipients.

METHODS

A duplex real-time PCR method was developed to amplify DNA from EBV and from a human gene. The EBV load was determined in peripheral blood mononuclear cells (PBMC), plasma and oropharyngeal tissue from 64 non-transplanted patients with lymphoid-hypertrophy (Non-Tx), 47 transplant recipients without PTLD (Tx), 54 recipients with PTLD (Tx-PTLD), and 66 blood donors (BD). WinPEPI, version 11.14 software was used for statistical analysis.

RESULTS

Analytical validation: the intra and inter-assays variation coefficients were less than 4.5% (EBV-reaction) and 3% (glyceraldehyde 3-phosphate dehydrogenase - GAPDH reaction). Linear ranges comprised 10(7)-10 EBV genome equivalents (gEq) (EBV-reaction) and 500,000-32 human gEq (GAPDH-reaction). The detection limit was 2.9 EBV gEq (EBV-reaction). Both reactions showed specificity. Application to clinical samples: higher levels of EBV were found in oropharyngeal tissue from transplanted groups with and without PTLD, compared to Non-Tx (p<0.05). The EBV load in PBMC from the groups of BD, Non-Tx, Tx and Tx-PTLD exhibited increasing levels (p<0.05). In BD, PBMC and plasma, EBV loads were undetectable.

CONCLUSIONS

The performance of the assay was suitable for the required clinical application. The assay may be useful to monitor EBV infection in transplant patients, in particular in laboratories from low-income regions that cannot afford to use commercial assays.

Life-threatening infection in transplant recipients

Modern post-transplant care pathways commonly encompass periods of critical care support. Infectious events account for many of these interactions making critical care physicians integral members of multidisciplinary transplant teams. Despite continuing advances in clinical care and infection prophylaxis, the morbidity and mortality attributable to infection post-transplant remains considerable. Emerging entities constantly add to the breadth of potential opportunistic pathogens. Individualized risk assessments, rapid and thorough diagnostic evaluation, and prompt initiation of appropriate antimicrobial therapies are essential. The approach to managing transplant recipients with infection in critical care is discussed and common and emerging opportunistic pathogens are reviewed.

Epidemiology and morbidity of Epstein-Barr virus infection in pediatric renal transplant recipients: a multicenter, prospective study

BACKGROUND

The epidemiology and morbidity of Epstein-Barr virus (EBV) infection in pediatric renal transplant recipients have been characterized insufficiently.

METHODS

In a prospective, multicenter study among 106 pediatric kidney allograft recipients aged 11.4 ± 5.9 years, we investigated the epidemiology of EBV infection and the relationship between EBV load, EBV serology, and EBV-related morbidity (posttransplant lymphoproliferative disease [PTLD] or symptomatic EBV infection, defined as flu-like symptoms or infectious mononucleosis).

RESULTS

EBV primary infection occurred in 27 of 43 (63%) seronegative patients and reactivation/reinfection in 28 of 63 (44%) seropositive patients. There was no association between the degree or duration of EBV load and EBV-related morbidity: The vast majority (17 of 18 [94%]) of patients with a high, persistent EBV load remained PTLD-free throughout a follow-up of 5.0 ± 1.3 years, while 2 of 3 (66%) patients with EBV-related PTLD exhibited only a low EBV load beforehand. Eight of 18 (44%) patients with a high, persistent EBV load remained asymptomatic during a follow-up of 5.3 ± 2.9 years. Multivariate analysis identified the EBV high-risk (D(+)/R(-)) serostatus (odds ratio [OR], 7.07; P < .05), the presence of human leukocyte antigen (HLA)-DR7 (OR, 5.65; P < .05), and the intensity of the immunosuppressive therapy (OR, 1.53; P < .01) as independent risk factors for the development of a symptomatic EBV infection.

CONCLUSIONS

Presence of EBV high-risk seroconstellation, HLA-DR7, and intensity of immunosuppressive therapy are significant risk factors for a symptomatic EBV infection, whereas there is no close association between the degree or duration of EBV load and EBV-related morbidity. Clinical Trials Registration. NCT00963248.

Infections in Heart and Lung Transplant Recipients

Patients undergoing thoracic organ transplantation procedures involving the heart or lung are at increased risk for developing a wide variety of infections due to their underlying immunosuppression and/or other factors. Lung transplant recipients are at high risk for developing infections caused by bacteria, viruses, and opportunistic fungi, whereas heart transplant recipients are at risk for developing infections caused by these same microorganisms, as well as parasitic infections, including toxoplasmosis and New World trypanosomiasis. This review will highlight the various infections that thoracic organ transplant recipients may develop following their procedures.

Herpes viruses in transplant recipients: HSV, VZV, human herpes viruses, and EBV

The herpes viruses are responsible for a wide range of diseases in patients following transplant, resulting from direct viral effects and indirect effects, including tumor promotion. Effective treatments and prophylaxis exist for the neurotropic herpes viruses HSV-1, HSV-2, varicella zoster virus, and possibly HHV-6. Antivirals seem to be less effective at prevention of the tumor-promoting effects of Epstein-Barr virus and HHV-8. Reduction in immunosuppression is the cornerstone to treatment of many diseases associated with herpes virus infections.

Infection and chronic allograft dysfunction

With the advent of more potent immunosuppressive regimens, the incidence of acute rejection following renal transplantation has declined sharply in recent years. In spite of this, long-term graft outcomes remain suboptimal because of relentless attrition by cumulated insults to the allograft. As acute rejection rates have declined, other causes of graft injury and loss have recently emerged. Among these, infectious diseases remain a persistent threat and can be associated with allograft dysfunction. This group includes nephropathy due to polyoma (BK) virus infection, cytomegalovirus disease, and bacterial infection (the latter most commonly arising from the urinary tract). Rarer infectious causes of chronic allograft dysfunction include cryoglobulinemia associated with hepatitis C, Epstein-Barr virus-associated posttransplant lymphoproliferative disease, and direct cytotoxicity from adenoviral infection or parvovirus B19.

Lymphoproliferative disorders after solid organ transplantation-classification, incidence, risk factors, early detection and treatment options

Posttransplant lymphoproliferative disorder (PTLD) is a heterogeneous disease group of benign and malignant entities. The new World Health Organisation classification introduced in 2008 distinguishes early lesions, polymorphic, monomorphic and classical Hodgkin lymphoma-type PTLD. Based on the time of appearance, early and late forms can be identified.PTLDs are the second most frequent posttransplantation tumors in adulthood, and the most frequent ones in childhood. The incidence varies with the transplanted organ-from 1%-2% following kidney transplantation to as high as 10% following thoracic organ transplantation-due to different intensities in immunosuppression. Immunocompromised state and Epstein-Barr virus (EBV) infection are the two major risk factors.In Europe and the US approximately 85% of PTLDs are of B-cell origin, and the majority are EBV-associated. Symptoms are often unspecific; extranodal, organ manifestations and central nervous system involvement is common. Early lesions respond well to a decrease in immunosuppression. Malignant entities are treated with rituximab, chemotherapy, radiotherapy and surgical therapy. Adoptive T-cell transfer represents a promising therapeutic approach. The prognosis is favorable in early PTLD, and poor in late PTLD. Five-year survival is 30% for high-grade lymphomas. The prognosis of EBV-negative lymphomas is worse.Lowering the risk of PTLD may be achieved by low dose maintenance immunosuppression, immunosuppressive drugs inhibiting cell proliferation, and special immunotherapy (e.g. interleukin-2 inhibitors). Early detection is especially important for high risk-e.g. EBV-negative-patients, where the appearance of EBV-DNA and the increase in its titer may help.

Prevention and treatment of infectious complications after solid organ transplantation in children

Effective prevention, diagnosis, and treatment of infectious diseases after transplantation are key factors contributing to the success of organ transplantation. Most transplant patients experience different kinds of infections during the first year after transplantation. Children are at particular risk of developing some types of infections by virtue of lack of immunity although they may be at risk for other types due the effect of immunosuppressive regimens necessary to prevent rejection. Direct consequences of infections result in syndromes such as mononucleosis, pneumonia, gastroenteritis, hepatitis, among other entities. Indirect consequences are mediated through cytokines, chemokines, and growth factors elaborated by the transplant recipient in response to microbial replication and invasion, which contribute to the net state of immunosuppression among other effects. This review summarizes the major infections that occur after pediatric organ transplantation, highlighting the current treatment and prevention strategies, based on the available data and/or consensus.

Significance of Epstein-Barr virus (EBV) load and Interleukin-10 in post-transplant lymphoproliferative disorders

The complex relationship between EBV, IL-10 and lymphomagenesis has been widely investigated and several studies have highlighted the diagnostic value of EBV DNA copies and serum IL-10, that may be considered as tumor markers. Notwithstanding the great number of data published in the last few years on the behavior of EBV DNA copies in the peripheral blood of transplanted patients, a threshold value significant for impending or overt post-transplant lymphoproliferative disorder (PTLD) has not yet been defined. Too many factors, both technical and clinicopathological, may affect the results of clinical studies, making their comparison difficult. On the contrary, although the role of IL-10 in PTLDs has been well documented, a sufficient number of studies exploring sensitivity and specificity of serum IL-10 measurement is lacking. The aim of this review is to summarise data on EBV load quantification and serum IL-10 detection in transplanted patients, providing clinicians with wide and useful information in order to improve bedside management of transplanted patients with regard to PTLDs occurrence and treatment.

Viruses

Viral infections are an important and often unrecognized component of disease in immunocompromised patients. The diagnosis and management of viral infections have expanded largely because of new quantitative molecular diagnostic assays. Well-recognized pathogens such as herpes simplex virus (HSV), cytomegalovirus (CMV), and respiratory viruses have been joined by newly recognized pathogens such as BK virus, human herpesvirus-6 (HHV-6), and human metapneumovirus in this highly susceptible patient population. The role of Epstein-Barr virus (EBV) and Human herpesvirus-8 (HHV-8) in lymphoproliferative diseases also continue to be clarified. As a result, the management of viral infections in patients with hematologic malignancies continues to be a growing challenge for the clinician.

Measuring Epstein-Barr virus (EBV) load: the significance and application for each EBV-associated disease

Because Epstein-Barr virus (EBV) is ubiquitous and persists latently in lymphocytes, simply detecting EBV is insufficient to diagnose EBV-associated diseases. Therefore, measuring the EBV load is necessary to diagnose EBV-associated diseases and to explore EBV pathogenesis. Due to the diverse biology of EBV, the significance of measuring EBV DNA and the optimal type of specimen differ among EBV-associated diseases. Recent advances in molecular technology have enabled the EBV genome to be quantitated rapidly and accurately. Real-time polymerase chain reaction (PCR) is a rapid and reliable method to quantify DNA and is widely used not only as a diagnostic tool, but also as a management tool for EBV-associated diseases. However, each laboratory currently measures EBV load with its own "homebrew" system, and there is no consensus on sample type, sample preparation protocol, or assay units. The EBV real-time PCR assay system must be standardised for large-scale studies and international comparisons.

Kinetics of Epstein-Barr virus DNA load in different blood compartments of pediatric recipients of T-cell-depleted HLA-haploidentical stem cell transplantation

Epstein-Barr virus (EBV) DNA levels in whole-blood samples of 54 pediatric patients receiving T-cell-depleted haploidentical hematopoietic stem cell transplantation (HSCT) in 2003 to 2007 were retrospectively compared with EBV DNA loads in peripheral blood mononuclear cells (PBMC). Determination of EBV DNA in whole blood missed 1 of 19 patients (5.2%), who tested positive for EBV DNA in PBMC. The analytical sensitivity of EBV DNA detection in whole-blood samples relative to that in PBMC was 94.7%. Regression analysis showed a significant correlation between DNA levels in PBMC and whole blood (r = 0.81; P < 0.001). Relative to that in PBMC, the appearance of EBV DNA in whole blood was delayed in 9/18 patients (median, 49 days; range, 6 to 226 days), while peak levels and clearance were reached simultaneously. Following peak levels, EBV DNA showed a slower decline in whole blood than in PBMC. In conclusion, (i) EBV DNA levels in PBMC were significantly correlated with those in whole blood; (ii) a differential kinetics of EBV DNA in the two blood compartments was observed; and (iii) monitoring of EBV DNA levels in whole blood appears to be a valuable alternative to PBMC in the follow-up of pediatric recipients of haploidentical T-cell-depleted HSCT.

Lymphoma after living donor kidney transplantation: an Iranian multicenter experience

INTRODUCTION

Post-transplant lymphoproliferative disorders (PTLD) are well-recognized complications in solid organ recipients. Limited data exist about the development of PTLDs in living kidney recipients. This study deals with a multicenter nationwide experience with kidney recipients from living donors.

METHODS

We reviewed data of PTLD patients from a total population of 6,500 patients transplanted at three different transplant centers in Iran from 1984 to 2006. We also compared their data with 2,250 normal kidney recipients of Baqiyatallah Transplant Center. Data were analyzed to determine potential correlates with the occurrence of PTLD and patient outcome.

RESULTS

Overall, 31 patients were diagnosed as having post-transplant lymphomas. The incidence of PTLD in our kidney transplant population comprised 0.47%. Sixteen (53%) PTLD patients were females, whereas 15 (47%) were males. The mean ages at transplantation and diagnosis were 37.1 and 41.9, respectively. Twelve (63%) patients died, and seven are alive. All deaths occurred within the 1st year after PTLD diagnosis. The mean time period from transplantation to diagnosis of PTLD was 64 (0.7-173) months. Localization of PTLD in the brain associated the worst outcome. Compared to non-PTLD patients, PTLD patients were significantly female predominated (51.6% vs. 32.2%; P = 0.03) and had lower age at transplantation (36.9 years vs. 42.9 years, respectively; P = 0.01). Patients under immunosuppressive regimens containing azathioprine were at higher risk for acquiring PTLDs compared to those with a MMF-containing regimen.

CONCLUSION

PTLD is a major threat to kidney transplant recipients. Immunosuppressive agents have a significant role in developing the disease. Early detection of the disease and using more safe immunosuppresants may have beneficial effects on patient outcomes and incidence of the disease.

Monomorphic post-transplant lymphoproliferative disorder of the tongue: case report and review of literature

Background

Post-transplant lymphoproliferative disorder (PTLD) is a spectrum of hematological diseases arising in context of immunosuppression after organ transplantation. PTLD can involve any organ; however, it is extremely rare in oral cavity.

Methods

Using morphologic and immunophenotypic approaches we have studied a case of monomorphic PTLD of the tongue that developed in a patient following unilateral kidney and pancreas transplantation on immunosuppressive therapy. Additionally, cases of PTLD in the oral cavity were reviewed in the English literature.

Results

The neoplasm showed large cell morphology and B-cell phenotype. In situ hybridization for Epstein-Barr virus was positive. Complete remission was obtained after decreasing immunosuppressive therapy. The patient remained in remission at 790 days' follow up.

Conclusion

This rare case increased our awareness of PTLD in the oral cavity of patients following solid organ transplantation and immunosuppressive therapy.

Second malignancies after allogeneic hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (allo-HCT) may prolong life and cure patients suffering from otherwise fatal diseases. However, the growing population of long-term survivors has led to the realization of multiple long-term complications, including the risk of second malignancies. Compared to the autologous setting, allo-HCT carries a much higher risk of posttransplant lymphoproliferative disorder (PTLD), which usually occurs within the first year after allo-HCT and is strongly associated with the Epstein-Barr virus (EBV). Treatment-related myelodysplastic syndromes (tMDS) and second leukemias are extremely rare. Both autologous and allo-HCT carry increased risks for second solid malignancies (SSM). The cumulative incidence of SSM continues to increase in each of the largest studies with as much as 20 years of follow-up, likely related to the long latency of radiation-related SSM. Systematic, prospective monitoring, vigilant screening processes, and well-maintained survivorship clinics and databases are absolute necessities, and should be included in the infrastructure of individual transplant centers and networks, with mandatory periodic reporting of second malignancy incidences. Primary care and transplant physicians alike must be aware of the risk of second malignancies after allo-HCT. Most importantly, guidelines should be developed in regard to screening and prevention of second malignancies, so that physicians can provide state-of-the-art counsel and care for the benefit of our patients.

Viral dynamics in transplant patients: implications for disease

Viral infections cause substantial morbidity and mortality in transplant patients. Quantifying viral loads is widely appreciated as a direct means to diagnose and monitor the course of viral infections. Recent studies indicate that the kinetics of viral load changes rather than single viral load measurements better correlate with organ involvement. In this Review, we will summarise the current knowledge regarding the kinetics of viruses relevant to transplantation including cytomegalovirus, Epstein-Barr virus, the herpes viruses 6 and 7, hepatitis C virus, GB virus C, adenovirus, and the emerging human polyomavirus type BK. We discuss the implications of viral kinetics for organ pathology as well as for the evaluation of antiviral interventions in transplant patients.

Gene expression of porcine lymphotrophic herpesvirus-1 in miniature Swine with posttransplant lymphoproliferative disorder

Porcine lymphotropic herpesvirus-1 (PLHV-1) is a gamma-herpesvirus related to Epstein-Barr virus (EBV) and associated with development of posttransplant lymphoproliferative disorder (PTLD) following allogeneic stem cell or spleen transplantation in miniature swine. Oligonucleotide microarrays were designed based on known open reading frames (ORFs) of PLHV-1. Expression was compared by cohybridization of cDNA from lymph nodes of PLHV-1+ swine after allogeneic spleen transplantation between either: 1) PTLD-affected and PTLD-unaffected swine; or 2) PTLD-affected swine vs. samples from the same animal prior to diagnosis. In PTLD-affected animals, consistent upregulation (nine ORFs) and downregulation (four ORFs) of PLHV-1 mRNA was observed in comparison to those without PTLD. No differences in gene expression were discovered at the time of clinical PTLD diagnosis compared to six to nine days prior to diagnosis in the same animals. This model provides insights into the pathogenesis of PTLD and, by extension, potential diagnostic and therapeutic tools for human EBV-associated PTLD.

Polyomavirus-associated nephropathy: update on BK virus-specific immunity

The human polyomavirus type 1, also called BK virus (BKV), causes polyomavirus-associated nephropathy (PVAN) in 1-10% of renal transplant recipients, with graft loss in over 50% of cases. The risk factors for PVAN are not conclusively defined and likely involve complementing determinants of recipient, graft, and virus. A central element seems to be the failing balance between BKV replication and BKV-specific immune control, which can result from intense triple immunosuppression, HLA-mismatches, prior rejection and anti-rejection treatment, or BKV-seropositive donor/seronegative recipient pairs. Consistent with this general hypothesis, the timely reduction of immunosuppression in kidney transplant recipients reduced graft loss to less than 10% of cases. However, the BKV-specific humoral and cellular immune response is not well characterized. Recent work from several groups suggest that changes in antibody titers and BKV-specific CD4+ and CD8+ T cells may help to better define the risk and the course of PVAN in renal transplant patients.

EBV-associated recurrent Hodgkin's disease after renal transplantation

Hodgkin's disease is recognized as part of the spectrum of post-transplantation lymphoproliferative disorders (PTLD), although it is still an uncommon de novo malignancy in this population. Epstein–Barr virus (EBV) has been linked to both post-transplant non-Hodgkin's lymphomas and Hodgkin's disease. We report a case of recurrent Hodgkin's disease in a patient who received a renal transplant in childhood and later developed EBV-associated Hodgkin's disease with remission after chemotherapy until subsequent relapse 9 years later that was successfully treated. To our knowledge, this is the first report of recurrent Hodgkin's disease in a transplant recipient. We briefly discuss the pathogenesis of and risk factors for EBV-related PTLD, utility of EBV load surveillance, and the options for treatment of PTLD including immunosuppression reduction, antiviral therapy, anti-CD20 monoclonal antibodies, cytotoxic T cells, and the possible roles of interferon-α and rapamycin.

Posttransplant Lymphoproliferative Disorders in Liver Transplanted Patients: A Report of Four Cases

BACKGROUND

Posttransplant lymphoproliferative disorders (PTLDs) are an uncommon but important cause of morbidity and mortality in solid organ transplant recipients. They are often the result of Epstein-Barr virus (EBV)-induced proliferation of B-lymphocytes in the setting of immunosuppression.

PATIENTS AND METHODS

We retrospectively analyzed four cases of PTLD after liver transplantation. In all patients immunosuppression was reduced and anti-CD20 monoclonal antibody (rituximab) was administered. In two of four patients, EBV viral load was positive in the peripheral blood, and gancyclovir was therefore also prescribed. Chemotherapy (CHOP) was used as a rescue in the event of treatment failure.

RESULTS

Even if no severe adverse events were observed during the treatment period, our treatment approach to PTLD was not effective, and only one patient out of four is still alive.

CONCLUSIONS

Well-designed clinical trials are necessary to evaluate the role of this combined approach in the treatment of PTLD in liver transplant recipients.

Clinical characteristics and outcomes of posttransplant lymphoproliferative disorders following allogeneic hematopoietic stem cell transplantation in Korea

Between 1995 and 2003, seven cases of posttransplant lymphoproliferative disorder (PTLD) were identified among 1,116 patients who received allogeneic hematopoietic stem cell transplantations (HSCT) at Catholic HSCT Center (overall incidence 0.6%). Five (71.4%) patients had episodes of acute graft-versus-host-disease (GVHD) and were treated with steroids. Cervical lymphadenopathy was observed in most cases (71.4%), but clinical symptoms varied depending on the involved sites. Pathologic findings varied: 1 case of plasmacytic hyperplasia, 3 of polymorphic PTLD, 2 of diffuse large B-cell lymphoma, 1 of large T-cell lymphoma, which proved to be associated with Epstein-Barr virus (EBV). The proportion of EBV-negative PTLD was 33.3%. Five patients demonstrated a good response to treatment (treatment response rate 71.4%). The overall mortality was 42.8%, and one death was directly attributable to PTLD. The incidence of PTLD is expected to increase, based on the rising use of grafts from alternative donors and recent clinical features of PTLD manifested by a disseminated and fulminant nature. It is necessary to have a high level of suspicion when monitoring patients and readily adopt prompt and effective cellular immunotherapy for PTLD.