Mark Harber

Cytomegalovirus glycoprotein-B vaccine with MF59 adjuvant in transplant recipients: a phase 2 randomised placebo-controlled trial

Summary Background Cytomegalovirus end-organ disease can be prevented by giving ganciclovir when viraemia is detected in allograft recipients. Values of viral load correlate with development of end-organ disease and are moderated by pre-existing natural immunity. Our aim was to determine whether vaccine-induced immunity could do likewise. Methods We undertook a phase-2 randomised placebo controlled trial in adults awaiting kidney or liver transplantation at the Royal Free Hospital, London, UK. Exclusion criteria were pregnancy, receipt of blood products (except albumin) in the previous 3 months, and simultaneous multiorgan transplantation. 70 patients seronegative and 70 seropositive for cytomegalovirus were randomly assigned from a scratch-off randomisation code in a 1:1 ratio to receive either cytomegalovirus glycoprotein-B vaccine with MF59 adjuvant or placebo, each given at baseline, 1 month and 6 months later. If a patient was transplanted, no further vaccinations were given and serial blood samples were tested for cytomegalovirus DNA by real-time quantitative PCR (rtqPCR). Any patient with one blood sample containing more than 3000 cytomegalovirus genomes per mL received ganciclovir until two consecutive undetectable cytomegalovirus DNA measurements. Safety and immunogenicity were coprimary endpoints and were assessed by intention to treat in patients who received at least one dose of vaccine or placebo. This trial is registered with ClinicalTrials.gov, NCT00299260. Findings 67 patients received vaccine and 73 placebo, all of whom were evaluable. Glycoprotein-B antibody titres were significantly increased in both seronegative (geometric mean titre 12 537 (95% CI 6593–23 840) versus 86 (63–118) in recipients of placebo recipients; p<0·0001) and seropositive (118 395; 64 503–217 272) versus 24 682 (17 909–34 017); p<0·0001) recipients of vaccine. In those who developed viraemia after transplantation, glycoprotein-B antibody titres correlated inversely with duration of viraemia (p=0·0022). In the seronegative patients with seropositive donors, the duration of viraemia (p=0·0480) and number of days of ganciclovir treatment (p=0·0287) were reduced in vaccine recipients. Interpretation Although cytomegalovirus disease occurs in the context of suppressed cell-mediated immunity post-transplantation, humoral immunity has a role in reduction of cytomegalovirus viraemia. Vaccines containing cytomegalovirus glycoprotein B merit further assessment in transplant recipients. Funding National Institute of Allergy and Infectious Diseases, Grant R01AI051355 and Wellcome Trust, Grant 078332. Sponsor: University College London (UCL).

Cytomegalovirus Replication Kinetics in Solid Organ Transplant Recipients Managed by Preemptive Therapy

After allotransplantation, cytomegalovirus (CMV) may be transmitted from the donor organ, giving rise to primary infection in a CMV negative recipient or reinfection in one who is CMV positive. In addition, latent CMV may reactivate in a CMV positive recipient. In this study, serial blood samples from 689 kidney or liver transplant recipients were tested for CMV DNA by quantitative PCR. CMV was managed using preemptive antiviral therapy and no patient received antiviral prophylaxis. Dynamic and quantitative measures of viremia and treatment were assessed. Median peak viral load, duration of viremia and duration of treatment were highest during primary infection, followed by reinfection then reactivation. In patients who experienced a second episode of viremia, the viral replication rate was significantly slower than in the first episode. Our data provide a clear demonstration of the immune control of CMV in immunosuppressed patients and emphasize the effectiveness of the preemptive approach for prevention of CMV syndrome and end organ disease. Overall, our findings provide quantitative biomarkers which can be used in pharmacodynamic assessments of the ability of novel CMV vaccines or antiviral drugs to reduce or even interrupt such transmission.

Major histocompatibility complex class I-related chain A allele mismatching, antibodies, and rejection in renal transplantation

Even when kidney allografts are well matched for human leukocyte antigen (HLA) and anti-HLA antibodies are not detected, graft rejection can still occur. There is evidence that some patients who lose their graft have antibodies specific for major histocompatibility complex (MHC) class I-related chain A (MICA) antigens. We investigated whether mismatching MICA alleles associates with MICA antibody production and graft rejection or dysfunction. MICA and HLA antibody screening in 442 recipients was performed, and specificities were confirmed in a subgroup of 227 recipients using single-antigen multiplex technology. For assignment of MICA antibody specificity, we used three independent assays. In addition, MICA alleles of 227 recipients and donors were determined by DNA sequencing. In all, 17 patients (7.5%) had MICA antibodies, and 13 patients (6%) developed MICA donor-specific antibodies (DSA). Multivariate analysis revealed MICA mismatching, as an independent significant factor associated with the presence of MICA antibodies (p = 0.009), and 14 mismatched MICA residues significantly correlated with MICA antibody production. MICA and HLA antibodies significantly associated with acute rejection (AR) and MICA DSA and HLA DSA correlated with decreased graft function by univariate and multivariate analysis. We conclude that mismatching for MICA epitopes in renal transplantation is a mechanism leading to production of MICA antibodies that associate with AR and graft dysfunction.

Prospective Monitoring of Epstein-Barr Virus DNA in Adult Renal Transplant Recipients During the Early Posttransplant Period: Role of Mycophenolate Mofetil

Background. Epstein-Barr virus (EBV) is associated with posttransplant lymphoproliferative disease. We monitored the incidence of EBV viraemia in adult renal transplant recipients and investigated the association with clinical parameters. Methods. Whole blood from 115 renal transplant patients was tested regularly by quantitative polymerase chain reaction (PCR) assay for EBV DNA during the first 90 days posttransplantation. Results. Sixty four of 115 (56%) patients had detectable EBV DNA in blood (>100 copies/mL) on at least one occasion. The median time to first DNA detection was 15 days post-transplant and median viral load was 598 copies/mL (range 119–53,649 copies/mL). Multivariate Cox-regression analyses showed that patients receiving mycophenolate mofetil (MMF) on the day of transplant had a significantly lower risk of EBV viraemia compared to those who received no MMF (Hazard ratio=0.518, 95% CI 0.307–0.875, p=0.014). Conclusions. EBV viraemia is common during the early posttransplant period in adult renal transplant recipients. Our results suggest a role of MMF in preventing EBV viraemia, however further work is required to identify the mechanism(s) involved.

Improving outcomes in patients with Acute Kidney Injury: the impact of hospital based automated AKI alerts.

Background Acute kidney injury (AKI) is a significant cause of morbidity and mortality. Early identification may improve the outcome and in 2012 our hospital introduced an automated AKI alert system for early detection and management of AKI. Objectives Using an automated AKI alert system we analysed whether early review and intervention by the Critical Care and Outreach (CCOT) team improved patient outcomes in AKI and whether serum bicarbonate was useful in predicting outcomes in patients with AKI. Methods In a retrospective analysis we identified patients who triggered an AKI alert from 20 April 2012 to 20 September 2013 and collected data on mortality, length of stay, need for intensive care admission and renal replacement therapy (RRT). Results 994 AKI alerts were generated and analysed. Patients with bicarbonate outside the normal range had significantly higher mortality. Bicarbonate <22 mmol/L was associated with a mortality of 25.7% (49/191) compared with 16.9% (39/231) when 22–29 mmol/L (p=0.047, χ2). Those patients reviewed ≥1 day after AKI alert by CCOT compared with those seen on the day of the alert had a 2.4 times increase in mortality and were 7 times more likely to require RRT acutely. Conclusions Electronically identified AKI alerts identify patients at high risk of morbidity and mortality. In this group AKI alerts preceded CCOT review by a mean of 2 days. This represents a window for supportive interventions, which may explain improved outcomes in those reviewed earlier. The addition of serum bicarbonate offers a further method of risk stratifying patients at greater risk of death.

Randomized Controlled Trials to Define Viral Load Thresholds for Cytomegalovirus Pre-Emptive Therapy

Background To help decide when to start and when to stop pre-emptive therapy for cytomegalovirus infection, we conducted two open-label randomized controlled trials in renal, liver and bone marrow transplant recipients in a single centre where pre-emptive therapy is indicated if viraemia exceeds 3000 genomes/ml (2520 IU/ml) of whole blood. Methods Patients with two consecutive viraemia episodes each below 3000 genomes/ml were randomized to continue monitoring or to immediate treatment (Part A). A separate group of patients with viral load greater than 3000 genomes/ml was randomized to stop pre-emptive therapy when two consecutive levels less than 200 genomes/ml (168 IU/ml) or less than 3000 genomes/ml were obtained (Part B). For both parts, the primary endpoint was the occurrence of a separate episode of viraemia requiring treatment because it was greater than 3000 genomes/ml. Results In Part A, the primary endpoint was not significantly different between the two arms; 18/32 (56%) in the monitor arm had viraemia greater than 3000 genomes/ml compared to 10/27 (37%) in the immediate treatment arm (p = 0.193). However, the time to developing an episode of viraemia greater than 3000 genomes/ml was significantly delayed among those randomized to immediate treatment (p = 0.022). In Part B, the primary endpoint was not significantly different between the two arms; 19/55 (35%) in the less than 200 genomes/ml arm subsequently had viraemia greater than 3000 genomes/ml compared to 23/51 (45%) among those randomized to stop treatment in the less than 3000 genomes/ml arm (p = 0.322). However, the duration of antiviral treatment was significantly shorter (p = 0.0012) in those randomized to stop treatment when viraemia was less than 3000 genomes/ml. Discussion The results illustrate that patients have continuing risks for CMV infection with limited time available for intervention. We see no need to alter current rules for stopping or starting pre-emptive therapy.

The Case ∣ Allograft dysfunction in a patient with sickle cell disease

The article focuses on the study concerning the diagnosis of acute renal allograft in patient with sickle cell disease. The 33 year old underwent several surgeries with immediate graft function. The percutaneous renal biopsy of the patient shows focal cortical necrosis and acute tubular damage coherent with ischemia. It concludes that the allograft sickling is the primary cause of the acute renal dysfunction in patients with sickle cell disease.

Prospective Multicenter Validation of Human Transitional B cell Cytokines as a Predictive Biomarker in Renal Transplantation

Introduction In renal transplantation, non-invasive biomarkers are needed to identify patients at risk for poor outcomes and guide pre-emptive therapy. In this prospective multicenter study, we assessed B cells and their cytokines as a predictive biomarker. Methods Based on prior data, we tested the ratio of IL-10:TNF&agr; expression in peripheral blood T1 transitional B cells (T1B) 2-4mo post-transplant, to perform as an early biomarker of clinical course. (Cytokines were examined by flow cytometry after 24hr stimulation with CD40L & CpG). Results 165 patients (transplanted in 2013-14) with serial biopsies (Bxs) (including 3&12mo protocol Bxs + for-cause Bxs) and serial blood draws (0, 1, 3, 6 & 12mos) served as the training set. Immunosuppression utilized Thymoglobulin induction followed by MPA+TAC maintenance. A low T1B IL10:TNF&agr; ratio at 3mo predicted acute rejection (AR) within the 1st yr (Fig1A). Notably, in patients with a normal Bx at 2-4mo, a low T1B cytokine ratio strongly predicted late AR (6-12mo; AUC 0.9, p<0.0001) with a lead time of > 7mo in 80% of the patients. These data were validated in an independent internal cohort (2015, n=74). Further, a low T1B cytokine ratio was associated with IFTA (12 mo) and graft loss/impending graft loss (eGFR<30ml/min & >30% fall from baseline) at 4yrs (Fig1B). The predictive value of this biomarker was not influenced by either opportunistic viral infections or by non-adherence. Figure. No caption available. Next, T1B cytokine ratio was validated in an external cohort (n=100) from the UK. Immunosuppression utilized Basiliximab induction followed by TAC+MMF maintenance. As protocol Bxs were not performed in this cohort, all AR was clinical. Again, the T1B cytokine ratio at 3mo strongly predicted AR within the 1st yr (Fig1C), and was associated with significantly greater graft loss/impending graft loss (Fig1D). B cells in high-risk patients express excessive TNF&agr; relative to IL-10. Culture of B cells from such patients with &agr;-TNF, reduced their TNF&agr; and increased their IL10 expression. Such B cells subsequently suppressed autologous ∝-CD3 stimulated T cell TNF&agr; while increasing IL10 expression. Thus, TNF blockade restored a normal B cell cytokine balance (Breg activity) in high-risk patients. Finally, &agr;-TNF inhibited in vitro differentiation of B cells to plasma cells, reduced their Ab secretion, and selectively increased their IL-10 expression. Conclusion Thus, T1B IL10:TNF&agr; ratio (2-4 mo) was tested and validated as a strong biomarker for subsequent renal allograft rejection and clinical course. Importantly, our data not only identifies patients in need of pre-emptive therapy, but provides rationale for therapeutic intervention based on TNF blockade. American Society of Transplantation. Roche Organ Transplant Reseacrh Foundation.

Hepatitis E infection in stem cell and solid organ transplantpatients: A cross-sectional study: The importance of HEV RNA screening in peri-transplant period

BACKGROUND Hepatitis E Virus (HEV) is a common cause of acute viral hepatitis worldwide. Typically associated with a self-limiting illness, infection may persist in immunosuppressed populations with significant morbidity and mortality. Based on clinical data published world-wide, UK blood safety guidance recommends the universal screening for HEV RNA of blood donors and donors of tissue, organs and stem cells. OBJECTIVES This cross-sectional study aimed to determine the point prevalence of HEV viraemia and clinical course of viraemic patients in the peri-transplant period in solid organ transplant (SOT) and haematopoietic stem cell transplant (HSCT) recipients transplanted over a 3-year period (2013-2015). STUDY DESIGN Nucleic acid extracts of whole blood from patients undergoing SOT or HSCT were tested by an in-house real-time reverse-transcriptase polymerase chain reaction assay for HEV RNA. Samples were tested at baseline (time of transplant), 30, 60 and 90 days post-transplant. RESULTS 870 patients (259 HSCT, 262 liver and 349 kidney transplant) were included with 2554 samples meeting the inclusion criteria. No kidney transplant patients had HEV viraemia at time of testing. One HSCT and three liver transplant patients were found to be HEV RNA positive. Overall this represented 0.46% of the patients testing positive for HEV viraemia. CONCLUSIONS Prevalence of HEV viraemia in SOT and HSCT patients in U.K. although higher than in the general population is low at baseline and remains low throughout the early post-transplant phase. Clearance of viraemia can be maintained despite ongoing immunosuppression. Prospective U.K. studies are necessary to inform screening policies in this population.