OKT3 and ganciclovir treatments are possibly related to the presence of Epstein-Barr virus in serum after liver transplantation

Infections in lung transplanted patients: A review

Lung transplantation can improve the survival of patients with severe chronic pulmonary disorders. However, the short- and long-term risk of infections can increase morbidity and mortality rates. A non-systematic review was performed to provide the most updated information on pathogen, host, and environment-related factors associated with the occurrence of bacterial, fungal, and viral infections as well as the most appropriate therapeutic options. Bacterial infections account for about 50% of all infectious diseases in lung transplanted patients, while viruses represent the second cause of infection accounting for one third of all infections. Almost 10% of patients develop invasive fungal infections during the first year after lung transplant. Pre-transplantation comorbidities, disruption of physical barriers during the surgery, and exposure to nosocomial pathogens during the hospital stay are directly associated with the occurrence of life-threatening infections. Empiric antimicrobial treatment after the assessment of individual risk factors, local epidemiology of drug-resistant pathogens and possible drug-drug interactions can improve the clinical outcomes.

Epstein-Barr virus and renal transplantation

Epstein-Barr virus (EBV) is a gamma herpesvirus associated with diseases ranging from asymptomatic viremia to post-transplant malignancies in kidney transplant recipients. EBV specifically is associated with post-transplantation lymphoproliferative disorder (PTLD), in kidney transplant recipients, with increased risk in EBV seronegative patients with EBV seropositive donors on intensified immunosuppression. The diagnosis of PTLD relies on clinical suspicion plus tissue biopsy with polymerase chain reaction (PCR) testing of blood currently used for risk determination in high-risk recipients. Therapeutic strategies for PTLD include reduction of immunosuppression, chemotherapy and rituximab, and consideration of sirolimus-based immunosuppression. Antivirals such as ganciclovir are used to prevent reactivation of cytomegalovirus and other herpes viruses but are not onco-therapeutic. Radiation therapy or surgery is indicated for bulky, disseminated or recalcitrant disease. Prognosis varies depending on the type of malignancy identified and stage of disease.

Detection of Epstein-Barr virus DNAemia after lung transplantation and its potential relationship with the development of post-transplant complications

BACKGROUND

Recent studies suggest that Epstein-Barr virus DNAemia (EBVd) may act as a surrogate marker of post-transplant immunosuppression. This hypothesis has not been tested so far in lung transplant (LT) recipients.

METHODS

We included 63 patients undergoing lung transplantation at our center between October 2008 and May 2013. Whole blood EBVd was systematically assessed by real-time polymerase chain reaction assay on a quarterly basis. The occurrence of late complications (overall and opportunistic infection [OI] and chronic lung allograft dysfunction [CLAD]) was analyzed according to the detection of EBVd within the first 6 months post transplantation.

RESULTS

Any EBVd was detected in 30 (47.6%) patients. Peak EBVd was higher in patients with late overall infection (2.23 vs. 1.73 log10 copies/mL; P = 0.026) and late OI (2.39 vs. 1.74 log10 copies/mL; P = 0.004). The areas under receiver operating characteristic curves for predicting both events were 0.806 and 0.871 respectively. The presence of an EBVd ≥2 log10 copies/mL during the first 6 months post transplantation was associated with a higher risk of late OI (adjusted hazard ratio [aHR] 7.92; 95% confidence interval [CI] 2.10-29.85; P = 0.002). Patients with detectable EBVd during the first 6 months also had lower CLAD-free survival (P = 0.035), although this association did not remain statistically significant in the multivariate analysis (aHR 1.26; 95% CI 0.87-5.29; P = 0.099).

CONCLUSIONS

Although preliminary in nature, our results suggest that the detection of EBVd within the first 6 months after transplantation is associated with the subsequent occurrence of late OI in LT recipients.

The Biology and Clinical Utility of EBV Monitoring in Blood

Epstein-Barr virus (EBV) DNA in blood can be quantified in peripheral blood mononuclear cells, in circulating cell-free (CCF) DNA specimens, or in whole blood. CCF viral DNA may be actively released or extruded from viable cells, packaged in virions or passively shed from cells during apoptosis or necrosis. In infectious mononucleosis, viral DNA is detected in each of these kinds of specimens, although it is only transiently detected in CCF specimens. In nasopharyngeal carcinoma, CCF EBV DNA is an established tumor marker. In EBV-associated Hodgkin lymphoma and in EBV-associated extranodal NK-/T-cell lymphoma, there is growing evidence for the utility of CCF DNA as a tumor marker.

Challenges and approaches for the development of safer immunomodulatory biologics

Immunomodulatory biologics are a class of biotechnology-derived therapeutic products that are designed to engage immune-relevant targets and are indicated in the treatment and management of a range of diseases, including immune-mediated inflammatory diseases and malignancies.

Despite their high specificity and therapeutic advantages, immmunomodulatory biologics have been associated with adverse reactions such as serious infections, malignancies and cytokine release syndrome, which arise owing to the on-target or exaggerated pharmacological effects of these drugs. Immunogenicity resulting in the generation of antidrug antibodies is another unwanted effect that leads to loss of efficacy and — rarely — hypersensitivity reactions.

For some adverse reactions, mitigating and preventive strategies are in place, such as stratifying patients on the basis of responsiveness to therapy and the risk of developing adverse reactions. These strategies depend on the availability of robust biomarkers for therapeutic efficacy and the risk of adverse reactions: for example, seropositivity for John Cunningham virus is a risk factor for progressive multifocal leukoencephalopathy. The development of effective biomarkers will greatly aid these strategies.

The development and design of safer immunomodulatory biologics is reliant on a detailed understanding of the nature of the disease, target biology, the interaction of the target with the immunomodulatory biologic and the inherent properties of the biologic that elicit unwanted effects.

The availability of in vitro and in vivo models that can be used to predict adverse reactions associated with immunomodulatory biologics is central to the development of safer immunomodulatory biologics. Some progress has been made in developing in vitro and in silico tests for predicting cytokine release syndrome and immunogenicity, but there is still a lack of models for effectively predicting infections and malignancies.

Two pathways can be followed in designing and developing safer immunomodulatory biologics. The first pathway involves generating a biologic that engages an alternative target or mechanism to produce the desired pharmacodynamic effect without the associated adverse reaction, and is followed when the adverse reaction cannot be dissociated from the target biology. The second pathway involves redesigning the biologic to 'engineer out' components within the biologic structure that trigger adverse effects or to alter the nature of the target–biologic interactions.

Owing to their specificity, immunomodulatory biologics generally have better safety profiles than small-molecule drugs. However, adverse effects such as an increased risk of infections or cytokine release syndrome are of concern. Here, Park and colleagues discuss the current strategies used to predict and mitigate these adverse effects and consider how they can be used to inform the development of safer immunomodulatory biologics.

Immunomodulatory biologics, which render their therapeutic effects by modulating or harnessing immune responses, have proven their therapeutic utility in several complex conditions including cancer and autoimmune diseases. However, unwanted adverse reactions — including serious infections, malignancy, cytokine release syndrome, anaphylaxis and hypersensitivity as well as immunogenicity — pose a challenge to the development of new (and safer) immunomodulatory biologics. In this article, we assess the safety issues associated with immunomodulatory biologics and discuss the current approaches for predicting and mitigating adverse reactions associated with their use. We also outline how these approaches can inform the development of safer immunomodulatory biologics.

Review article: medical management of the liver transplant recipient - a primer for non-transplant doctors

BACKGROUND

Survival 10 years after orthotopic liver transplantation now approaches 65%. Consequently, community doctors must manage the metabolic and neoplastic complications of orthotopic liver transplantation in an ageing population.

AIMS

To review common sources of morbidity and mortality in long-term orthotopic liver transplantation recipients, and to make evidence-based recommendations regarding their management.

METHODS

Pertinent studies and reviews were identified by literature search through PubMed. Where evidence-based recommendations could not be gleaned from the literature, expert opinion was obtained from syllabi of national meetings.

RESULTS

The two most common causes of morbidity and mortality in orthotopic liver transplantation recipients are atherosclerotic vascular disease and de novo malignancy. The pathogenesis of many complications begins before orthotopic liver transplantation, and many are potentially modifiable. Most complications, however, can be directly ascribed to immunosuppressive agents. Despite improvements in our understanding of the pathogenesis and epidemiology of the metabolic and neoplastic complications of orthotopic liver transplantation, remarkably few randomized-controlled studies exist to define their optimal management.

CONCLUSIONS

Orthotopic liver transplantation recipients experience and succumb to the same afflictions of old age as non-transplant patients, but with greater frequency and at an earlier age. Most recommendations regarding surveillance for, and treatment of, medical complications of orthotopic liver transplantation remain based upon expert opinion rather than evidence-based medicine.

Review of Epstein–Barr virus and post-transplant lymphoproliferative disorder post-solid organ transplantation (Review Article)

Post-transplant lymphoproliferative disorder (PTLD) following solid organ transplantation is an important form of post-transplant malignancy. PTLD is typically associated with Epstein-Barr virus (EBV) and occurs in the setting of profound immunosuppression resulting in a deficiency of EBV-specific cytotoxic T lymphocytes (CTL). Predisposing factors include EBV mismatch between donor and recipient, use of immunosuppression especially T-cell depletive therapies and genetic predisposition of recipients. The standard approach has been to reduce immunosuppression but is often insufficient to induce tumour regression. Further understanding of the immunobiology of PTLD has resulted in improved monitoring techniques (including EBV viral load determined by polymerase chain reaction) and newer treatment options. Recent work has highlighted a potential role for dendritic cells in both the pathogenesis and treatment of PTLD. Current treatment modalities include adoptive immunotherapy using ex vivo generated autologous EBV-specific CTL or allogeneic CTL, cytokine therapies, antiviral agents, and more recently, rituximab and dendritic-cell based therapies. This review focuses on the developments and progress in the pathogenesis, diagnosis and treatment of PTLD.