Claire Atkinson

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).

Human Herpesvirus 6 Chromosomal Integration in Immunocompetent Patients Results in High Levels of Viral DNA in Blood, Sera, and Hair Follicles

ABSTRACT Six immunocompetent patients with human herpesvirus 6 (HHV-6) chromosomal integration had HHV-6 and β-globin DNA quantified in various samples by PCR. The mean HHV-6 DNA concentration (log10 copies/milliliter) in blood was 7.0 (≥1 HHV-6 DNA copies/leukocyte), and in serum it was 5.3 (≥1 HHV-6 DNA copies/lysed cell). The mean HHV-6 DNA load (log10 copies)/hair follicle was 4.2 (≥1 copies/hair follicle cell), demonstrating that viral integration is not confined to blood cells. The characteristically high HHV-6 DNA levels in chromosomal integration may confound laboratory diagnosis of HHV-6 infection and should be given due consideration.

Transmission of Integrated Human Herpesvirus 6 through Stem Cell Transplantation: Implications for Laboratory Diagnosis

We identified a stem cell donor with chromosomally integrated human herpesvirus (HHV)-6 and monitored the recipient for HHV-6 after transplantation. The appearance and subsequent increase in HHV-6 load paralleled engraftment and an increase in white blood cell count. Fluorescent in situ hybridization analysis showed integrated HHV-6 on chromosome band 17p13.3 in the donor and in the recipient after transplantation but not in the recipient before transplantation. The increase in viral load due to the genetic transmission of integrated HHV-6 could have been misinterpreted as substantial active infection and, thus, led to the administration of toxic antiviral therapy. We suggest that the confounding influence of integration be considered in laboratory investigations associating HHV-6 with disease.

Human Herpesvirus 6 DNA Levels in Cerebrospinal Fluid Due to Primary Infection Differ from Those Due to Chromosomal Viral Integration and Have Implications for Diagnosis of Encephalitis

ABSTRACT The prevalence and concentration of human herpesvirus 6 (HHV-6) DNA in the cerebrospinal fluid (CSF) of the immunocompetent in primary infection was compared with that in viral chromosomal integration. Samples from 510 individuals with suspected encephalitis, 200 young children and 310 older children and/or adults, and 12 other patients were tested. HHV-6 DNA concentration (log10 copies/ml) was measured in CSF, serum, and whole blood using PCR. Serum HHV-6 immunoglobulin G antibody was measured by indirect immunofluorescence. Primary infection was defined by antibody seroconversion and/or a low concentration of HHV-6 DNA (<3.0 log10 copies/ml) in a seronegative serum. Chromosomal integration was defined by a high concentration of viral DNA in serum (≥3.5 log10 copies/ml) or whole blood (≥6.0 log10 copies/ml). The prevalences of CSF HHV-6 DNA in primary infection and chromosomal integration were 2.5% and 2.0%, respectively, in the young children (<2 years) and 0% and 1.3%, respectively, in the older children and/or adults. The mean concentration of CSF HHV-6 DNA in 9 children with primary infection (2.4 log10 copies/ml) was significantly lower than that of 21 patients with viral chromosomal integration (4.0 log10 copies/ml). Only HHV-6B DNA was found in primary infection, whereas in viral integration, 4 patients had HHV-6A and 17 patients HHV-6B. Apart from primary infection, chromosomal integration is the most likely cause of HHV-6 DNA in the CSF of the immunocompetent. Our results show that any diagnosis of HHV-6 encephalitis or other type of active central nervous system infection should not be made without first excluding chromosomal HHV-6 integration by measuring DNA load in CSF, serum, and/or whole blood.

Congenital cytomegalovirus: association between dried blood spot viral load and hearing loss

Aim: To investigate the relation between cytomegalovirus (CMV) viral load on dried blood spots (DBS) from newborn biochemical screening (“Guthrie”) cards, and sensorineural hearing loss (SNHL) in congenital CMV. Design: Cross-sectional study with retrospective case-note review. Setting: Seven paediatric audiology departments in the United Kingdom. Patients: 84 children, median age 7 years: 43 with known congenital CMV, 41 with unexplained SNHL. Interventions: Half a DBS was tested for CMV DNA viral load by quantitative real-time polymerase chain reaction (PCR). Main outcome measures: Pure tone average hearing thresholds (0.5–4 kHz). Results: DBS CMV DNA viral load significantly correlated with hearing thresholds for the worse and better hearing ears (Spearman’s rank correlations: r = 0.445, p = 0.008 and r = 0.481, p = 0.004 respectively). Multivariable logistic regression showed that the effect of DBS viral load on the risk of SNHL remained important, when age and central nervous system involvement had been taken into account (odds ratio (OR) 2.76, 95% confidence interval (CI) 1.14 to 6.63, p = 0.024). The mean log DBS viral load was significantly higher in children with SNHL than in those with normal hearing (2.69 versus 1.64, 95% CI −1.84 to −0.27, p = 0.01). 8/35 (23%) children with unexplained SNHL tested positive for CMV DNA on DBS. One false positive result was obtained. Conclusion: The risk of SNHL increased with DBS viral load. Further studies should investigate whether DBS CMV testing has a role in identifying asymptomatic congenitally infected neonates at risk of SNHL, and whether antiviral treatment can reduce this risk.

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.

Use of stored dried blood spots for retrospective diagnosis of congenital CMV

The diagnosis of congenital cytomegalovirus infection cannot be made with certainty in children presenting after the perinatal period, unless stored early samples are available for diagnostic testing. This has led to uncertainty in confirming the overall contribution of CMV to hearing loss and neurodevelopmental impairment. The use of dried blood spots (DBSs) to retrospectively diagnose infection in children with compatible symptoms may be helpful diagnostically although there are ongoing uncertainties regarding the stability of viral DNA in cards, the risk of contamination between cards, and sensitivity and specificity in a clinical setting. This report aims to address these areas and evaluate the use of DBS testing in our hands in the United Kingdom to date. Results from testing artificially prepared cards and cards from three populations of children suggest a high specificity for congenital CMV infection and a good sensitivity for cases where sensorineural hearing loss is caused by congenital CMV. J. Med. Virol. 81:1394–1398, 2009.

Recombination of Globally Circulating Varicella Zoster Virus

ABSTRACT Varicella-zoster virus (VZV) is a human herpesvirus, which during primary infection typically causes varicella (chicken pox) and establishes lifelong latency in sensory and autonomic ganglia. Later in life, the virus may reactivate to cause herpes zoster (HZ; also known as shingles). To prevent these diseases, a live-attenuated heterogeneous vaccine preparation, vOka, is used routinely in many countries worldwide. Recent studies of another alphaherpesvirus, infectious laryngotracheitis virus, demonstrate that live-attenuated vaccine strains can recombine in vivo, creating virulent progeny. These findings raised concerns about using attenuated herpesvirus vaccines under conditions that favor recombination. To investigate whether VZV may undergo recombination, which is a prerequisite for VZV vaccination to create such conditions, we here analyzed 115 complete VZV genomes. Our results demonstrate that recombination occurs frequently for VZV. It thus seems that VZV is fully capable of recombination if given the opportunity, which may have important implications for continued VZV vaccination. Although no interclade vaccine-wild-type recombinant strains were found, intraclade recombinants were frequently detected in clade 2, which harbors the vaccine strains, suggesting that the vaccine strains have already been involved in recombination events, either in vivo or in vitro during passages in cell culture. Finally, previous partial and complete genomic studies have described strains that do not cluster phylogenetically to any of the five established clades. The additional VZV strains sequenced here, in combination with those previously published, have enabled us to formally define a novel sixth VZV clade. IMPORTANCE Although genetic recombination has been demonstrated to frequently occur for other human alphaherpesviruses, herpes simplex viruses 1 and 2, only a few ancient and isolated recent recombination events have hitherto been demonstrated for VZV. In the present study, we demonstrate that VZV also frequently undergoes genetic recombination, including strains belonging to the clade containing the vOKA strain.

Incidence and Dynamics of Epstein-Barr Virus Reactivation After Alemtuzumab-Based Conditioning for Allogeneic Hematopoietic Stem-Cell Transplantation

Background. Reactivation of Epstein-Barr virus (EBV) infection and posttransplant lymphoproliferative disorder (PTLD) pose a significant risk after T-cell-depleted (TCD) allogeneic hematopoietic stem-cell transplantation (HSCT). The pattern of EBV reactivation in patients receiving allogeneic HSCT, incorporating in vivo or in vitro alemtuzumab as the method of TCD, is not known. Methods. Monitoring for EBV DNA was performed by quantitative polymerase chain reaction on whole blood in 111 consecutive adults undergoing HSCT using alemtuzumab-based TCD. Patients with more than 40,000 copies/mL were screened for PTLD, followed by the withdrawal of immunosuppression and a single infusion of rituximab. Results. The 2-year cumulative incidence of EBV DNAemia was 40.3%. In vivo alemtuzumab was associated with earlier EBV reactivation than in vitro alemtuzumab (100-day incidence 22.7% vs. 2.8%, P=0.006). Eighteen patients (16%) had EBV DNAemia of more than 40,000 copies/mL. In evaluable patients, the initial rate of increase in EBV DNA levels was significantly faster in those who went on to treatment with rituximab than in patients who were left untreated (mean doubling time 3.5 days vs. 4.2 days, P=0.003). Rituximab treatment induced rapid declines in EBV DNA with an average half-life of 1.2±0.7 days. Only one patient (0.9%) had histologic confirmation of PTLD and subsequently attained a complete remission with rituximab that persists at 18 months. Conclusions. Alemtuzumab-based TCD is associated with a high frequency of EBV reactivation but a low (<1%) risk of PTLD using a strategy of preemptive rituximab therapy.

Soluble CD30: A serum marker for Epstein-Barr virus-associated lymphoproliferative diseases

The soluble form of CD30 (sCD30), a member of tumor necrosis factor receptor superfamily, has been used as a marker of disease activity in various lymphomas. Epstein–Barr virus (EBV) is a potent stimulator of CD30 expression. The study aims to evaluate whether sCD30 can be used as a diagnostic marker for EBV‐associated infectious mononucleosis (IM) and post‐transplant lymphoproliferative disease (PTLD). Plasma from EBV seropositive healthy controls (N = 90), acute IM patients (n = 90), non‐PTLD heart/lung transplant recipients (N = 30) and EBV‐positive PTLD patients (N = 23) was tested for sCD30 using a commercially available ELISA kit. EBV DNA was tested by real time quantitative polymerase chain reaction assay. Significantly higher sCD30 levels were observed in acute IM patients (median 242.9 ng/ml) compared to EBV seropositive controls (median 15.7 ng/ml; P < 0.0001). These levels were highest in IM patients within 14 days of onset of illness. PTLD patients had significantly higher sCD30 levels (median 94 ng/ml) than healthy controls (P < 0.0001) and transplant patients (median 27 ng/ml; P = 0.0007). EBV DNA was detected mostly in acute IM and PTLD patients. In both cases there was a significant correlation between sCD30 and EBV DNA levels in plasma (P < 0.0001). This study demonstrates that sCD30 and EBV DNA levels can be used as potential markers for diagnosis of IM and PTLD. J. Med. Virol. 83:311–316, 2011.