Heart transplantation in Val142Ile mutation in the modern era: A single center experience.

Little is known about the post heart transplantation management of extra cardiac manifestations in patients with hereditary transthyretin amyloid cardiomyopathy (hATTR-CM) in the new era of disease modifying treatment for ATTR amyloidosis. This is a retrospective study of all patients with hATTR-CM associated with the Val142Ile variant who underwent heart transplantation (HT) from January 2014 to February 2022. All 10 patients with the Val142Ile mutation were successfully transplanted, with a 1 year survival post heart transplantation (HT) of 90%, comparable to an age, sex, and race matched cohort of patients transplanted for non-amyloid indications. However, 4 (40%) of these patients developed progressive extracardiac manifestations requiring initiation of TTR silencer therapy with the small interfering RNA (siRNA) drug patisiran, which was well tolerated with no significant side effects in this population. We recommend formal neurologic evaluation and assessment of extracardiac manifestations annually as part of routine post-transplant care, and disease modifying therapy, aimed at TTR stabilization or silencing, should be initiated in the context of previously untreated extracardiac manifestations or evidence of subclinical neuropathy to prevent progression.

Association of race and gender with primary caregiver relationships and eligibility for advanced heart failure therapies.

BACKGROUND: Caregiver support is considered necessary after heart transplant (HT) and left ventricular assist device (LVAD) for patients with end-stage heart failure (HF). Few studies have demonstrated how caregivers differ by gender and race, and whether that impacts therapy eligibility. METHODS: We examined caregiver relationships among 674 patients (32% women, 55% Black) evaluated at Emory University from 2011 to 2017. Therapy readiness was assessed using the Stanford Integrated Assessment for Transplant (SIPAT). Evaluation outcome according to caregiver relationship was compared using χ2 analysis. Multivariable logistic regression determined the association between caregiver and eligibility according to gender and race. RESULTS: Women and Black patients were less likely to have spouses as their support person (P < .001). Women were less likely to be considered eligible for advanced therapies (adjusted odds ratio [aOR] .64, 95% confidence interval [CI] .46-.89; P = .008), with Black women having lower eligibility than White women (aOR .28, 95% CI .11-.72; P = .008). Social support and SIPAT scores did not significantly influence eligibility by gender or race. CONCLUSION: Lack of caregiver support is considered a relative contraindication to advanced therapies. Type of caregiver in our cohort varied according to race and gender but did not explain differences in eligibility for advanced therapies.

Ventricular arrhythmia burden and implantable cardioverter-defibrillator outcomes in transthyretin cardiac amyloidosis.

BACKGROUND: As targeted treatments for amyloid transthyretin cardiomyopathy (ATTR-CM) are becoming available, we aim to characterize the rates of ventricular arrhythmias (VAs), implantable cardioverter-defibrillator (ICD) utilization, and their impact on survival. METHODS: This is a retrospective cohort study of 130 patients with ATTR-CM diagnosed at Emory University's Cardiac Amyloidosis Center between April 2012 and September 2020. VAs were defined as nonsustained or sustained ventricular tachycardia and ventricular fibrillation. RESULTS: Of 130 patients, 42 had wild-type disease (wtATTR) and 88 had hereditary variants (hATTR), most commonly Val122Ile (89%). At ATTR-CM diagnosis, 80 (62%) patients had EF ≤ 40% consistent with systolic heart failure. Of the 69 (53%) patients with documented VAs significantly higher rates occurred among those with EF ≤ 40% compared with EF > 40% (67% vs. 28%, p = .001). Thirty-two patients (25 hATTR, 7 wtATTR) had primary prevention ICDs implanted. Eight (25%) of these patients received appropriate ICD therapy while two (6%) experienced inappropriate therapy. Comparing patients with EF ≤ 35% with and without ICDs did not reveal any survival difference (3.3 ± 0.5 vs. 2.8 ± 0.4 years, p = .699). CONCLUSIONS: High rates of VAs and appropriate ICD therapy were found among a unique cohort of largely hereditary ATTR-CM patients with a high rate of systolic heart failure.

Sex differences in eligibility for advanced heart failure therapies.

OBJECTIVES: We investigated sex-based differences in eligibility for and outcomes after receipt of advanced heart failure (HF) therapies. BACKGROUND: Although women are more likely to die from HF than men, registry data suggest that women are less likely to receive heart transplant (HT) or left ventricular assist device (LVAD) for largely unknown reasons. METHODS: We performed a single-center retrospective cohort study of patients evaluated for advanced HF therapies from 2012 to 2016. Logistic regression was used to determine the association of sex with eligibility for HT/LVAD. Competing risks and Kaplan-Meier analysis were used to examine survival. RESULTS: Of 569 patients (31% women) evaluated, 223 (39.2%) were listed for HT and 81 (14.2%) received destination (DT) LVAD. Women were less likely to be listed for HT (adjusted odds ratio [OR] 0.36, 95% confidence interval [CI] 0.21-0.61; P < .0001), based on allosensitization (P < .0001) and obesity (P = .02). Women were more likely to receive DT LVAD (adjusted OR 2.29, 95% CI 1.23-4.29; P = .01). Survival was similar between men and women regardless of whether they received HT and DT LVAD or were ineligible for therapy. CONCLUSION: Women are less likely to be HT candidates, but more likely to receive DT LVAD.

Validating patient prioritization in the 2018 Revised United Network for Organ Sharing Heart Allocation System: A single-center experience.

The 2018 Revised United Network for Organ Sharing Heart Allocation System (HAS) was proposed to reclassify status 1A candidates into groups of decreasing acuity; however, it does not take into account factors such as body mass index (BMI) and blood group which influence waitlist (WL) outcomes. We sought to validate patient prioritization in the new HAS at our center. We retrospectively evaluated patients listed for heart transplantation (n = 214) at Emory University Hospital from 2011 to 2017. Patients were reclassified into the 6-tier HAS. Multistate modeling and competing risk analysis were used to compare outcomes of transplantation and WL death/deterioration between new tiers. Additionally, a stratified sensitivity analysis by BMI and blood group was performed. Compared with tier 4 patients, there was progressively increasing hazard of WL death/deterioration in tier 3 (HR: 2.52, 95% CI: 1.37-4.63, P = .003) and tier 2 (HR: 5.03, 95% CI: 1.99-12.70, P < .001), without a difference in transplantation outcome. When stratified by BMI and blood group, this hierarchical association was not valid in patients with BMI ≥30 kg/m2 and non-O blood groups in our cohort. Therefore, the 2018 HAS accurately prioritizes the sickest patients in our cohort. Factors such as BMI and blood group influence this relationship and iterate that the system can be further refined.

Myocardial Energetics and Heart Failure: a Review of Recent Therapeutic Trials.

PURPOSE OF REVIEW: Several novel therapeutics being tested in patients with heart failure are based on myocardial energetics. This review will provide a summary of the recent trials in this area, including therapeutic options targeting various aspects of cellular and mitochondrial metabolism. RECENT FINDINGS: Agents that improve the energetic balance in myocardial cells have the potential to improve clinical heart failure status. The most promising therapies currently under investigation in this arena include (1) elamipretide, a cardiolipin stabilizer; (2) repletion of iron deficiency with intravenous ferrous carboxymaltose; (3) coenzyme Q10; and (4) the partial adenosine receptor antagonists capadenoson and neladenosone. Myocardial energetics-based therapeutics are groundbreaking in that they utilize novel mechanisms of action to improve heart failure symptoms, without causing the adverse neurohormonal side effects associated with current guideline-based therapies. The drugs appear likely to be added to the heart failure therapy armamentarium as adjuncts to current regimens in the near future.

Alloying ZnS in the hexagonal phase to create high-performing transparent conducting materials.

Alloyed zinc sulfide (ZnS) has shown promise as a relatively inexpensive and earth-abundant transparent conducting material (TCM). Though Cu-doped ZnS has been identified as a high-performing p-type TCM, the corresponding n-doped ZnS has, to date, been challenging to synthesize in a controlled manner; this is because the dopant atoms compete with hole-inducing zinc vacancies near the conduction band minimum as the most thermodynamically stable intrinsic point defects. We thus aim to identify the most promising n-type ZnS-based TCM, with the optimal combination of physical stability, transparency, and electrical conductivity. Using a relatively new method for calculating the free energy of both the sphalerite (cubic) and wurtzite (hexagonal) phases of undoped and doped ZnS, we find that doped ZnS is more stable in the hexagonal structure. This, for the first time, fundamentally explains previous experimental observations of the coexistence of both phases in doped ZnS; hence, it profoundly impacts future work on sulfide TCMs. We also employ hybrid density functional theory calculations and a new carrier transport model, AMSET (ab initio model for mobility and Seebeck coefficient using the Boltzmann transport equation), to analyze the defect physics and electron mobility of the different cation- (B, Al, Ga, In) and anion-doped (F, Cl, Br, I) ZnS, in both the cubic and hexagonal phases, at various dopant compositions, temperatures, and carrier concentrations. Among all doped ZnS candidates, Al-doped ZnS (AZS) exhibits the highest dopant solubility, largest electronic band gap, and highest electrical conductivity of 3830, 1905, and 321 S cm(-1), corresponding to the possible carrier concentrations of n = 10(21), 10(20), and 10(19) cm(-3), respectively, at the optimal 6.25% dopant concentration of Al and the temperature of 300 K.

Myocardial perfusion imaging-derived left ventricular strain: Regional abnormalities associated with transthyretin cardiac amyloidosis.

Background: Transthyretin (ATTR) cardiac amyloidosis is associated with an apical-sparing strain pattern on TTE. We hypothesize that strain indices derived from myocardial perfusion imaging (MPI) can identify this abnormality. Methods: A group with ATTR amyloidosis was compared to age-matched controls with LVH but without amyloidosis who underwent PET or SPECT MPI. Strain values were used to calculate the apical strain index (ASI), apex-to-base ratio (ABR), and ejection fraction to global strain ratio in multiple planes. Results: A direct comparison using Welch's t-tests reveals 6 statistically significant metrics. After regression analysis, the circumferential ASI and ABR at rest remain significantly greater in the ATTR group compared to controls. Conclusion: MPI-derived strain from the circumferential plane at rest may distinguish cardiac amyloidosis from other forms of LVH. If these findings are confirmed with validation studies, routine MPI-derived strain analysis could identify patients with subclinical amyloidosis who may benefit from further testing.

Outcomes among heart transplant recipients following acute coronary syndrome: A nationwide population based study.

BACKGROUND: For patients with refractory heart failure despite optimal medical therapy, orthotopic heart transplantation (OHT) remains the treatment of choice. Since transplanted hearts have variable cardiac denervation and acute coronary syndrome often presents as a silent myocardial infarction or with atypical symptoms, the true impact of ACS on outcomes within this population needs more study. The aim of this study is to evaluate in-hospital mortality in post-transplant patients with ACS. METHODS: Utilizing data from the 2002-15 Nationwide Inpatient Sample database, patients with a primary diagnosis of acute coronary syndrome among those with prior heart transplantation were included. A risk adjusted regression analysis was performed to assess if ACS post-OHT had an independent impact on the risk of in-hospital mortality. A 2:1 propensity matching was used to match ACS patients with and without OHT, respectively to assess differences in mortality. RESULTS: A total of 3,224,073 patients with a primary diagnosis of acute coronary syndrome were included, of which 842 (0.03%) were heart-transplant recipients. The type of ACS: NSTEMI (76.0% vs 74.5%; p = 0.32) and STEMI (24.8% vs 26.7%; p = 0.21) between heart transplant and non-heart transplant patients was similar in both groups. Following ACS, patients with heart transplant were more likely to have accompanying shock of any etiology (15.6% vs 3.8%; p < 0.001) and cardiogenic shock (11.2% vs 2.6%; p < 0.001) compared to those with native hearts. OHT patients also had significantly higher in-hospital mortality (14.3% vs. 3.7%; p < 0.001) that remain significant following regression analysis (aOR 3.6, 95% CI 2.8-4.5; p < 0.001) irrespective of the presence of cardiogenic shock compared to native hearts. This relationship remained consistent following propensity matching where patients with OHT had significantly higher in-hospital mortality (13.5% vs. 7%; p < 0.001). CONCLUSIONS: ACS following OHT was more likely to have accompanying cardiogenic shock. ACS in the setting of prior OHT remained a strong independent predictor of higher mortality as compared to native hearts.

Left Ventricular Assist Devices and Pregnancy: Systematic Review of Existing Literature and Case Report.

Although pregnancy is generally contraindicated in advanced heart failure (AHF), successful pregnancies have been observed in patients with left ventricular assist devices (LVADs). The number of pregnancies in patients with LVADs is increasing, yet optimal management strategies remain undefined. Additionally, no successful pregnancies have been reported with the HeartMate 3 (HM3) (Abbott) LVAD. A systematic review of pregnancy in patients with LVADs was prepared utilizing 3 major scientific databases. We also present the first reported case of successful pregnancy and delivery in a patient supported by an HM3 LVAD. The systematic search yielded 95 results. After filtering to include only relevant citations, eight unique cases were identified. Cases were compared on the basis of several clinical factors. Although pregnancies supported by LVADs are medically complex, several cases of successful deliveries have been observed. Clinical management between cases, however, did vary significantly. Several areas requiring further study were identified.

Peptidoglycan induced expression of peroxisome proliferator-activated receptor γ in mouse peritoneal macrophages: role of ERK and JNK MAP kinases.

The peroxisome proliferator-activated receptor (PPAR) γ plays an important role in macrophage inflammatory homeostasis. Here we investigate the cross talk between PPARγ and TLR2 signaling pathway in mouse peritoneal macrophages. Real time RT-PCR and immunoblot analysis revealed that peptidoglycan (PGN) treatment of macrophages leads to biphasic effect on PPARγ expression i.e. an early upregulation and a late suppression. Inhibition of ERK MAP kinase by PD98059 abolished the early and rapid induction of PPARγ, while the inhibition of JNK MAP kinase by SP600125 nullifies the late inhibitory effect on the PPARγ expression in a dose-dependent manner. Furthermore, PPARγ knockdown macrophages showed enhanced NF-κB activity after PGN treatment. PGN treatment also enhances PPARγ interaction with p65 as observed by immunoprecipitation. This interaction may inhibit NF-κB (p65) activity as increased nuclear localization of p65 was observed in PPARγ knockdown macrophages after PGN treatment. PPARγ knockdown also increased the PGN-induced inflammatory cytokines (TNF-α, IL-1ß, IL-12p40) production. Thus, our observations suggest that PGN induces PPARγ expression which is regulated by MAPKs activation and this enhanced PPARγ in turn attenuate NF-κB activity probably via enhancing p65 nuclear export. These results provide insight into how these pathways could be modulated in inflammatory diseases.

Evaluation of striate keratopathy after manual small-incision cataract surgery and its final outcomes in a tertiary hospital.

Purpose: To study the demographic profile, contributing and precipitating factors, the severity of striate keratopathy and its relation with endothelial cell count, and evaluate the final treatment outcome of striate keratopathy. Methods: This observational: analytical cohort study was conducted on 75 patients developing striate keratopathy after MSICS in the immediate postoperative period. Demographic profile, preoperative risk factors, and intraoperative complications were evaluated retrospectively. Postoperatively, slit-lamp grading of striate keratopathy was done, and specular microscopy of both eyes was taken. Treatment of striate keratopathy was initiated, and patients were followed up for 6 to 10 weeks for improvement. Results: Striate keratopathy was most commonly associated with surgeries performed by resident surgeons (92%), longer duration of surgery, associated predisposing factors, and intraoperative or postoperative complications. On postoperative day 1, the majority of patients had moderate and severe striate keratopathy (66% and 32%, respectively). It was associated with significant endothelial cell loss (ECL) at the final follow-up (P = 0.0016). Striate keratopathy resolved in 97.3% of patients, irrespective of the treatment with hypertonic saline. At 6 to 10 weeks, 92% of patients achieved a BCVA of ≥6/9. Conclusion: A careful preoperative evaluation, adequate training of resident surgeons, meticulous surgical technique, and prompt management of postoperative complications can lead to a decrease in the incidence of striate keratopathy in the majority of cases. The use of hypertonic saline eye drops does not change the final outcome, and most cases resolve spontaneously during follow-up.

High-density lipoprotein therapy: is there hope?

OPINION STATEMENT: The treatment of lipid abnormalities generally has focused on low-density lipoprotein cholesterol (LDL-C) reduction based on extensive clinical trials and the National Cholesterol Education Program Adult Treatment Panel III guidelines. Unfortunately, it has become increasingly clear that a significant percentage of patients continue to have cardiovascular events despite being on LDL-C-lowering medications and having LDL-C levels below 100 mg/dL. Numerous epidemiologic studies have associated low high-density lipoprotein cholesterol (HDL-C) levels with increased risk of cardiovascular disease (CVD). Furthermore, recent data show that up to 55% of patients hospitalized for CVD have low HDL-C levels (<40 mg/dL) on admission, suggesting a possible target for further reducing CVD. Low HDL-C also is part of the atherogenic phenotype associated with obesity, glucose intolerance, and hypertension, termed the metabolic syndrome, and often is seen in patients with insulin resistance states. In general, the first line of therapy for increasing HDL-C in patients with levels below 40 mg/dL is lifestyle modification with smoking cessation, exercise, weight loss, and diet modifications. The pharmacologic treatment of isolated low HDL-C in patients without coronary disease is controversial but should be considered in those with a strong family history of CVD. In patients with coronary artery disease and isolated low HDL-C, statins remain the first-line therapy and should be instituted after lifestyle modifications, with the goal of increasing HDL-C above 40 mg/dL. If concomitant hypertriglyceridemia is present, a fibrate or niacin should be considered. Although statins do offer some HDL-C-raising properties, they tend to have modest effects. If treatment goals have not been achieved with either lifestyle changes or statin therapy, then the next agent of choice is niacin. Among the various HDL-C-raising therapies, niacin continues to be the most potent therapeutic option available. There are several novel HDL-C therapies in the research pipeline; however, only one class of medications is relatively close to clinical use, the cholesteryl ester transferase protein (CETP) inhibitors. Although one of the CETP inhibitors, torcetrapib, has received much negative attention from a large randomized trial showing increased mortality associated with its use, the overall class of therapeutic agents may still hold some benefit. Currently, two new CETP inhibitors without the off-target effects of torcetrapib are undergoing clinical research. Overall, the use of HDL-C-modifying agents likely will increase over the next decade.

Profiling HPV-16-specific T cell responses reveals broad antigen reactivities in oropharyngeal cancer patients.

Cellular immunotherapeutics targeting the human papillomavirus (HPV)-16 E6 and E7 proteins have achieved limited success in HPV-positive oropharyngeal cancer (OPC). Here we have conducted proteome-wide profiling of HPV-16-specific T cell responses in a cohort of 66 patients with HPV-associated OPC and 22 healthy individuals. Unexpectedly, HPV-specific T cell responses from OPC patients were not constrained to the E6 and E7 antigens; they also recognized E1, E2, E4, E5, and L1 proteins as dominant targets for virus-specific CD8+ and CD4+ T cells. Multivariate analysis incorporating tumor staging, treatment status, and smoking history revealed that treatment status had the most significant impact on HPV-specific CD8+ and CD4+ T cell immunity. Specifically, the breadth and overall strength of HPV-specific T cell responses were significantly higher before the commencement of curative therapy than after therapy. These data provide the first glimpse of the overall human T cell response to HPV in a clinical setting and offer groundbreaking insight into future development of cellular immunotherapies for HPV-associated OPC patients.

Errors in Electronic Health Record-Based Data Query of Statin Prescriptions in Patients With Coronary Artery Disease in a Large, Academic, Multispecialty Clinic Practice.

BACKGROUND: With the recent implementation of the Medicare Quality Payment Program, providers face increasing accountability for delivering high-quality care. Such pay-for-performance programs aim to leverage systematic data captured by electronic health record (EHR) systems to measure performance; however, the fidelity of EHR query for assessing performance has not been validated compared with manual chart review. We sought to determine whether our institution's methodology of EHR query could accurately identify cases in which providers failed to prescribe statins for eligible patients with coronary artery disease. METHODS AND RESULTS: A total of 9459 patients with coronary artery disease were seen at least twice at the Emory Clinic between July 2014 and June 2015, of whom 1338 (14.1%, 95% confidence interval 13.5-14.9%) had no statin prescription or exemption per EHR query. A total of 120 patient cases were randomly selected and reviewed by 2 physicians for further adjudication. Of the 120 cases initially classified as statin prescription failures, only 21 (17.5%; 95% confidence interval, 11.7-25.3%) represented true failure following physician review. CONCLUSIONS: Sole reliance on EHR data query to measure quality metrics may lead to significant errors in assessing provider performance. Institutions should be cognizant of these potential sources of error, provide support to medical providers, and form collaborative data management teams to promote and improve meaningful use of EHRs. We propose actionable steps to improve the accuracy of EHR data query that require hypothesis testing and prospective validation in future studies.

Racial differences in the development of de-novo donor-specific antibodies and treated antibody-mediated rejection after heart transplantation.

BACKGROUND: Despite improvements in outcomes after heart transplantation, black recipients have worse survival compared with non-black recipients. The source of such disparate outcomes remains largely unknown. We hypothesize that a propensity to generate de-novo donor-specific antibodies (dnDSA) and subsequent antibody-mediated rejection (AMR) may account for racial differences in sub-optimal outcomes after heart transplant. In this study we aimed to determine the role of dnDSA and AMR in racial disparities in post-transplant outcomes. METHODS: This study was a single-center, retrospective analysis of 137 heart transplant recipients (81% male, 48% black) discharged from Emory University Hospital. Patients were classified as black vs non-black for the purpose of our analysis. Kaplan-Meier and Cox regression analyses were used to evaluate the association between race and selected outcomes. The primary outcome was the development of dnDSA. Secondary outcomes included treated AMR and a composite of all-cause graft dysfunction or death. RESULTS: After 3.7 years of follow-up, 39 (28.5%) patients developed dnDSA and 19 (13.8%) were treated for AMR. In multivariable models, black race was associated with a higher risk of developing dnDSA (hazard ratio [HR] 3.65, 95% confidence interval [CI] 1.54 to 8.65, p = 0.003) and a higher risk of treated AMR (HR 4.86, 95% CI 1.26 to 18.72, p = 0.021) compared with non-black race. Black race was also associated with a higher risk of all-cause graft dysfunction or death in univariate analyses (HR 2.10, 95% CI 1.02 to 4.30, p = 0.044). However, in a multivariable model incorporating dnDSA, black race was no longer a significant risk factor. Only dnDSA development was significantly associated with all-cause graft dysfunction or death (HR 4.85, 95% CI 1.89 to 12.44, p = 0.001). CONCLUSION: Black transplant recipients are at higher risk for the development of dnDSA and treated AMR, which may account for racial disparities in outcomes after heart transplantation.

Evaluation of striate keratopathy after manual small-incision cataract surgery and its final outcomes in a tertiary hospital

Purpose: To study the demographic profile, contributing and precipitating factors, the severity of striate keratopathy and its relation with endothelial cell count, and evaluate the final treatment outcome of striate keratopathy. Methods: This observational analytical cohort study was conducted on 75 patients developing striate keratopathy after MSICS in the immediate postoperative period. Demographic profile, preoperative risk factors, and intraoperative complications were evaluated retrospectively. Postoperatively, slit-lamp grading of striate keratopathy was done, and specular microscopy of both eyes was taken. Treatment of striate keratopathy was initiated, and patients were followed up for 6 to 10 weeks for improvement. Results: Striate keratopathy was most commonly associated with surgeries performed by resident surgeons (92%), longer duration of surgery, associated predisposing factors, and intraoperative or postoperative complications. On postoperative day 1, the majority of patients had moderate and severe striate keratopathy (66% and 32%, respectively). It was associated with significant endothelial cell loss (ECL) at the final follow-up (P = 0.0016). Striate keratopathy resolved in 97.3% of patients, irrespective of the treatment with hypertonic saline. At 6 to 10 weeks, 92% of patients achieved a BCVA of ?6/9. Conclusion: A careful preoperative evaluation, adequate training of resident surgeons, meticulous surgical technique, and prompt management of postoperative complications can lead to a decrease in the incidence of striate keratopathy in the majority of cases. The use of hypertonic saline eye drops does not change the final outcome, and most cases resolve spontaneously during follow-up

Designing an effective vaccine to prevent Epstein-Barr virus-associated diseases: challenges and opportunities.

INTRODUCTION: Epstein-Barr virus (EBV) is a ubiquitous herpesvirus associated with a number of clinical manifestations. Primary EBV infection in young adolescents often manifests as acute infectious mononucleosis and latent infection is associated with multiple lymphoid and epithelial cancers and autoimmune disorders, particularly multiple sclerosis. Areas covered: Over the last decade, our understanding of pathogenesis and immune regulation of EBV-associated diseases has provided an important platform for the development of novel vaccine formulations. In this review, we discuss developmental strategies for prophylactic and therapeutic EBV vaccines which have been assessed in preclinical and clinical settings. Expert commentary: Major roadblocks in EBV vaccine development include no precise understanding of the clinical correlates of protection, uncertainty about adjuvant selection and the unavailability of appropriate animal models. Recent development of new EBV vaccine formulations provides exciting opportunities for the formal clinical assessment of novel formulations.

Short-course rapamycin treatment enables engraftment of immunogenic gene-engineered bone marrow under low-dose irradiation to permit long-term immunological tolerance.

BACKGROUND: Application of genetically modified hematopoietic stem cells is increasingly mooted as a clinically relevant approach to protein replacement therapy, immune tolerance induction or conditions where both outcomes may be helpful. Hematopoietic stem and progenitor cell (HSPC)-mediated gene therapy often requires highly toxic pretransfer recipient conditioning to provide a 'niche' so that transferred HSPCs can engraft effectively and to prevent immune rejection of neoantigen-expressing engineered HSPCs. For widespread clinical application, reducing conditioning toxicity is an important requirement, but reduced conditioning can render neoantigen-expressing bone marrow (BM) and HSC susceptible to immune rejection if immunity is retained. METHODS: BM or HSPC-expressing OVA ubiquitously (actin.OVA) or targeted to MHC II+ cells was transferred using low-dose (300 cGy) total body irradiation. Recipients were administered rapamycin, cyclosporine or vehicle for 3 weeks commencing at BM transfer. Engraftment was determined using CD45 congenic donors and recipients. Induction of T-cell tolerance was tested by immunising recipients and analysing in-vivo cytotoxic T-lymphocyte (CTL) activity. The effect of rapamycin on transient effector function during tolerance induction was tested using an established model of tolerance induction where antigen is targeted to dendritic cells. RESULTS: Immune rejection of neoantigen-expressing BM and HSPCs after low-dose irradiation was prevented by a short course of rapamycin, but not cyclosporine, treatment. Whereas transient T-cell tolerance developed in recipients of OVA-expressing BM administered vehicle, only when engraftment of neoantigen-expressing BM was facilitated with rapamycin treatment did stable, long-lasting T-cell tolerance develop. Rapamycin inhibited transient effector function development during tolerance induction and inhibited development of CTL activity in recipients of OVA-expressing BM. CONCLUSIONS: Rapamycin acts to suppress acquisition of transient T-cell effector function during peripheral tolerance induction elicited by HSPC-encoded antigen. By facilitating engraftment, short-course rapamycin permits development of long-term stable T-cell tolerance.