Waning of vaccine-induced immunity to measles in kidney transplanted children

Serological responses to immunization during nephrosis in infants with congenital nephrotic syndrome of the Finnish type

Background

Pretransplant vaccination is generally recommended to solid organ transplant recipients. In infants with congenital nephrotic syndrome (CNS), the immune response is hypothetically inferior to other patients due to young age and urinary loss of immunoglobulins, but data on the immunization response in severely nephrotic children remain scarce. If effective, however, early immunization of infants with CNS would clinically be advantageous.

Methods

We investigated serological vaccine responses in seven children with CNS who were immunized during nephrosis. Antibody responses to measles-mumps-rubella -vaccine (MMR), a pentavalent DTaP-IPV-Hib -vaccine (diphtheria, tetanus, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b), varicella vaccine, combined hepatitis A and B vaccine, and pneumococcal conjugate vaccine (PCV) were measured after nephrectomy either before or after kidney transplantation.

Results

Immunizations were started at a median age of 7 months [interquartile range (IQR) 7-8], with a concurrent median proteinuria of 36,500 mg/L (IQR 30,900-64,250). Bilateral nephrectomy was performed at a median age of 20 months (IQR 14-25), and kidney transplantation 10-88 days after the nephrectomy. Antibody levels were measured at median 18 months (IQR 6-23) after immunization. Protective antibody levels were detected in all examined children for hepatitis B (5/5), Clostridium tetani (7/7), rubella virus (2/2), and mumps virus (1/1); in 5/6 children for varicella; in 4/6 for poliovirus and vaccine-type pneumococcal serotypes; in 4/7 for Haemophilus influenzae type B and Corynebacterium diphtheriae; in 1/2 for measles virus; and in 2/5 for hepatitis A. None of the seven children had protective IgG levels against Bordetella pertussis.

Conclusion

Immunization during severe congenital proteinuria resulted in variable serological responses, with both vaccine- and patient-related differences. Nephrosis appears not to be a barrier to successful immunization.

Spotting a potential threat: Measles among pediatric solid organ transplantation recipients

BACKGROUND

Low-vaccination rates worldwide have led to the re-emergence of vaccine-preventable infections, including measles. Immunocompromised patients, including pediatric solid organ transplant (SOT) recipients, are at risk for measles because of suboptimal vaccination, reduced or waning vaccine immunity, lifelong immunosuppression, and global re-emergence of measles.

OBJECTIVES

To review published cases of measles in pediatric SOT recipients to heighten awareness of its clinical manifestations, summarize diagnostic and treatment strategies, and identify opportunities to optimize prevention.

METHODS

We conducted a literature review of published natural measles infections in SOT recipients ≤21 years of age, summarizing management and outcomes. We describe measles epidemiology, recommended diagnostics, treatment, and highlight prevention strategies.

RESULTS

There are seven published reports of measles infection in 12 pediatric SOT recipients, the majority of whom were unvaccinated or incompletely vaccinated. Subjects had atypical or severe clinical presentations, including lack of rash and complications, most frequently with encephalitis and pneumonitis, resulting in 33% mortality. Updated recommendations on testing and vaccination are provided. Treatment options beyond supportive care and vitamin A are limited, with no approved antivirals.

CONCLUSION

While measles is infrequently reported in pediatric SOT recipients, morbidity and mortality remain significant. A high index of suspicion is warranted in susceptible SOT recipients with clinically compatible illness or exposure. Providers must recognize this risk, educate families, and be aware of both classic and atypical presentations of measles to rapidly identify, isolate, and diagnose measles in pediatric SOT recipients. Continued efforts to optimize measles vaccination both pre- and post-SOT are warranted.

Immunological Memory and Affinity Maturation After Vaccination in Patients With Propionic Acidemia

Earlier studies have recommended routine childhood immunization in patients with propionic acidemia (PA); however, the literature presents insufficient data on the response to vaccines, notably specific IgG concentrations and avidity maturation, after measles, mumps, rubella (MMR), and diphtheria/tetanus (DiphtTe) vaccinations in this population. In patients with PA, cellular and humoral changes of the immune system (e.g. a decreased CD4+ T cell count, with a reversal of CD4/CD8 T cell ratio, a deficient gamma-globulin fraction, and in one case a decreased lymphocyte blastogenesis) have been reported. Former reports also detected pancytopenias accompanying febrile infections in PA patients. In the current study, we analyzed vaccine-specific IgG concentrations and avidity maturation after MMR and DiphtTe vaccinations in 10 patients with PA. Compared to gender and age matched controls, all 10 had protective IgG concentrations for at least one tested antigen, and in 6 out of 10 patients high relative avidity indices for measles and rubella were detected. In summary, the present study revealed a sufficient immune response and outcome, indicating an acceptable humoral memory in patients with PA after booster vaccinations.

Seroprotection against measles in previously vaccinated children with difficult-to-treat nephrotic syndrome

BACKGROUND

Children with nephrotic syndrome (NS) are vulnerable to infections. Measles infection is an important cause of morbidity and mortality in immunosuppressed children. A suboptimal seroprotection against measles has been shown in immunocompromised children. There is limited published literature on measles immunity in children with difficult-to-treat nephrotic syndrome (DTNS). We compared the proportions of children with DTNS and healthy controls who were seroprotected against measles.

METHODS

This was a cross-sectional study. Measles-specific IgG antibodies of 108 children with DTNS (3 to 10 years of age) and an equal number of age-matched healthy controls were measured. All children had received two doses of measles-containing vaccine at 9-12 and 16-24 months of age under routine immunisation programme. Serum measles IgG antibody titres were measured by indirect ELISA. The assay results were interpreted as (1) > 11 NTU (NovaTec Units), positive/seroprotective titres; (2) 9-11, equivocal; and (3) < 9 NTU, negative. Inter- and intra-group comparisons were made to identify the disease characteristics related to seroprotection status.

RESULTS

The proportion of children with protective anti-measles antibodies (n = 70, 65%) was significantly lower in DTNS as compared to controls (n = 88, 81.48%) (p = 0.005). Their median [IQR] antibody titres were also significantly lower than those in controls (14.1 [14] NTU vs. 18.3 [15.2] NTU (p = 0.001). The age, gender, clinical subtype, duration of disease, and type of immunosuppressive therapy were not significantly different between seroprotected and non-seroprotected children with DTNS.

CONCLUSION

A significantly lower percentage of fully vaccinated children with DTNS were seroprotected against measles compared to healthy controls. A higher resolution version of the Graphical abstract is available as Supplementary information.

A hidden menace? Cytomegalovirus infection is associated with reduced cortical gray matter volume in major depressive disorder

Human cytomegalovirus (HCMV) infection is associated with neuropathology in patients with impaired immunity and/or inflammatory diseases. However, the association between gray matter volume (GMV) and HCMV has never been examined in major depressive disorder (MDD) despite the presence of inflammation and impaired viral immunity in a subset of patients. We tested this relationship in two independent samples consisting of 179 individuals with MDD and 41 healthy controls (HC) (sample 1) and 124 MDD participants and 148 HCs (sample 2). HCMV positive (HCMV+) and HCMV negative (HCMV-) groups within each sample were balanced on up to 11 different clinical/demographic variables using inverse probability of treatment weighting. GMV of 87 regions was measured with FreeSurfer. There was a main effect of HCMV serostatus but not diagnosis that replicated across samples. Relative to HCMV- subjects, HCMV+ subjects in sample 1 showed a significant reduction of volume in six regions (p_uncorrected < 0.05). The reductions in GMV of the right supramarginal gyrus (standardized beta coefficient (SBC) = -0.26) and left fusiform gyrus (SBC = -0.25) in sample 1 were replicated in sample 2: right supramarginal gyrus (p_uncorrected < 0.05, SBC = -0.32), left fusiform gyrus (P_FDR < 0.01, SBC = -0.51). Posthoc tests revealed that the effect of HCMV was driven by differences between the HCMV+ and HCMV- MDD subgroups. HCMV IgG level, a surrogate marker of viral activity, was correlated with GMV in the left fusiform gyrus (r = -0.19, P_uncorrected = 0.049) and right supramarginal gyrus (r = -0.19, p_uncorrected = 0.043) in the HCMV+ group of sample 1. Conceivably, HCMV infection may be a treatable source of neuropathology in vulnerable MDD patients.

Safety and efficacy of early vaccination with live attenuated measles vaccine for hematopoietic stem cell transplant recipients and solid organ transplant recipients

BACKGROUND AND OBJECTIVE

Vaccination with the live attenuated measles vaccine is currently recommended two years after hematopoietic stem cell transplantation (HSCT) and generally contraindicated after solid organ transplantation (SOT) due to safety concerns. However, in the last few years new data on the administration of the measles vaccine to HSCT recipients less two years post-transplantation and to SOT recipients have become available. This new data may change current guidelines and practices. The objective of this review is to provide an overview of the current data on the safety and efficacy of early measles vaccination for HSCT- and SOT recipients.

METHOD

PubMed and EMBASE were searched from the earliest date available through October 2019 to identify all research that reported on the safety and efficacy of measles vaccination after SOT or less than two years after HSCT.

RESULTS

A total of ten studies was included in this review. In the six studies that evaluated the efficacy of measles vaccination after SOT, seroconversion rates ranged from 41 to 100% after one dose and 73 to 100% after two doses. In the four studies that evaluated the efficacy of measles vaccination less than two years after HSCT, seroconversion rates ranged from 33 to 100% after one dose and 100% after two doses. In all studies, the administration of the measles vaccine after transplantation was considered to be safe. There were no cases of infection with the attenuated vaccine strain, and there were no adverse events related to the vaccination.

CONCLUSION

Data on the administration of the measles vaccine after SOT and less than two years after HSCT is scarce. However, the current data available suggest that it is efficacious and well tolerable. Therefore, early measles vaccination could be considered in selected groups of SOT- and HSCT recipients during increased measles transmission or an outbreak setting.

Investigating the Interaction between Negative Strand RNA Viruses and Their Hosts for Enhanced Vaccine Development and Production

The current pandemic has highlighted the ever-increasing risk of human to human spread of zoonotic pathogens. A number of medically-relevant zoonotic pathogens are negative-strand RNA viruses (NSVs). NSVs are derived from different virus families. Examples like Ebola are known for causing severe symptoms and high mortality rates. Some, like influenza, are known for their ease of person-to-person transmission and lack of pre-existing immunity, enabling rapid spread across many countries around the globe. Containment of outbreaks of NSVs can be difficult owing to their unpredictability and the absence of effective control measures, such as vaccines and antiviral therapeutics. In addition, there remains a lack of essential knowledge of the host–pathogen response that are induced by NSVs, particularly of the immune responses that provide protection. Vaccines are the most effective method for preventing infectious diseases. In fact, in the event of a pandemic, appropriate vaccine design and speed of vaccine supply is the most critical factor in protecting the population, as vaccination is the only sustainable defense. Vaccines need to be safe, efficient, and cost-effective, which is influenced by our understanding of the host–pathogen interface. Additionally, some of the major challenges of vaccines are the establishment of a long-lasting immunity offering cross protection to emerging strains. Although many NSVs are controlled through immunisations, for some, vaccine design has failed or efficacy has proven unreliable. The key behind designing a successful vaccine is understanding the host–pathogen interaction and the host immune response towards NSVs. In this paper, we review the recent research in vaccine design against NSVs and explore the immune responses induced by these viruses. The generation of a robust and integrated approach to development capability and vaccine manufacture can collaboratively support the management of outbreaking NSV disease health risks.

The Role of Systems Vaccinology in Understanding the Immune Defects to Vaccination in Solid Organ Transplant Recipients

Solid organ transplant recipients (SOTRs) are at increased risk for many infections, whether viral, bacterial, or fungal, due to immunosuppressive therapy to prevent organ rejection. The same immune defects that render transplanted patients susceptible to infection dampen their immune response to vaccination. Therefore, it is vital to identify immune defects to vaccination in transplant recipients and methods to obviate them. These methods can include alternative vaccine composition, dosage, adjuvants, route of administration, timing, and re-vaccination strategies. Systems biology is a relatively new field of study, which utilizes high throughput means to better understand biological systems and predict outcomes. Systems biology approaches have been used to help obtain a global picture of immune responses to infections and vaccination (i.e. systems vaccinology), but little work has been done to use systems biology to improve vaccine efficacy in immunocompromised patients, particularly SOTRs, thus far. Systems vaccinology approaches may hold key insights to vaccination in this vulnerable population.

Towards Precision Vaccines: Lessons From the Second International Precision Vaccines Conference

Other than clean drinking water, vaccines have been the most effective public health intervention in human history, yet their full potential is still untapped. To date, vaccine development has been largely limited to empirical approaches focused on infectious diseases and has targeted entire populations, potentially disregarding distinct immunity in vulnerable populations such as infants, elders, and the immunocompromised. Over the past few decades innovations in genetic engineering, adjuvant discovery, formulation science, and systems biology have fueled rapid advances in vaccine research poised to consider demographic factors (e.g., age, sex, genetics, and epigenetics) in vaccine discovery and development. Current efforts are focused on leveraging novel approaches to vaccine discovery and development to optimize vaccinal antigen and, as needed, adjuvant systems to enhance vaccine immunogenicity while maintaining safety. These approaches are ushering in an era of precision vaccinology aimed at tailoring immunization for vulnerable populations with distinct immunity. To foster collaboration among leading vaccinologists, government, policy makers, industry partners, and funders from around the world, the Precision Vaccines Program at Boston Children's Hospital hosted the 2nd International Precision Vaccines Conference (IPVC) at Harvard Medical School on the 17th-18th October 2019. The conference convened experts in vaccinology, including vaccine formulation and adjuvantation, immunology, cell signaling, systems biology, biostatistics, bioinformatics, as well as vaccines for non-infectious indications such as cancer and opioid use disorder. Herein we review highlights from the 2nd IPVC and discuss key concepts in the field of precision vaccines.

The Tat Protein of HIV-1 Prevents the Loss of HSV-Specific Memory Adaptive Responses and Favors the Control of Viral Reactivation

The development of therapeutic strategies to control the reactivation of the Herpes Simplex Virus (HSV) is an unaddressed priority. In this study, we evaluated whether Tat, a HIV-1 protein displaying adjuvant functions, could improve previously established HSV-specific memory responses and prevent viral reactivation. To this aim, mice were infected with non-lethal doses of HSV-1 and, 44 days later, injected or not with Tat. Mice were then monitored to check their health status and measure memory HSV-specific cellular and humoral responses. The appearance of symptoms associated with HSV-reactivation was observed at significantly higher frequencies in the control group than in the Tat-treated mice. In addition, the control animals experienced a time-dependent decrease in HSV-specific Immunoglobulin G (IgG), while the Tat-treated mice maintained antibody titers over time. IgG levels were directly correlated with the number of HSV-specific CD8⁺ T cells, suggesting an effect of Tat on both arms of the adaptive immunity. Consistent with the maintenance of HSV-specific immune memory, Tat-treated mice showed a better control of HSV-1 re-infection. Although further studies are necessary to assess whether similar effects are observed in other models, these results indicate that Tat exerts a therapeutic effect against latent HSV-1 infection and re-infection by favoring the maintenance of adaptive immunity.

Acquired hypogammaglobulinemia and pathogen-specific antibody depletion after solid organ transplantation in human immunodeficiency virus infection: A brief report

Hypogammaglobulinemia (HGG) frequently occurs in recipients after types of (SOT). The incidence and significance of HGG in HIV+ recipients of SOT are just being explored. We reported that 12% of the recipients in the SOT in multi-center HIV-TR (HIV-TR) Study developed moderate or severe HGG at 1 year. In LT recipients, this was associated with serious infections and death. We have now further characterized the decreased antibodies in HIV+ SOT recipients who developed HGG. We measured the levels of pathogen-specific antibodies and poly-specific self-reactive antibodies (PSA) in relation to total IgG levels from serial serum samples for 20 HIV+ SOT recipients who developed moderate to severe HGG following SOT. Serum antibody levels to measles, tetanus toxoid, and HIV-1 were determined by EIA. Levels of PSAs were determined by incubating control lymphocytes with patient serum, staining with anti-human IgG Fab-FITC, and analysis by flow cytometry. Levels of PSA were higher compared to healthy, HIV-uninfected controls at pre-transplant baseline and increased by weeks 12 and 26, but the changes were not significant. Likewise, anti-HIV antibody levels remained unchanged over time. In contrast, antibody levels against measles and tetanus were significantly reduced from baseline by week 12, and did not return to baseline, even after 2 years. For HIV patients who develop moderate to severe HGG after transplant, the reduction in IgG levels is associated with a significant decrease in pathogen-specific antibody titers, while PSA levels and anti-HIV antibodies are unchanged. This may contribute to infectious complications and other clinical endpoints.

OMIC Technologies and Vaccine Development: From the Identification of Vulnerable Individuals to the Formulation of Invulnerable Vaccines

Routine vaccination is among the most effective clinical interventions to prevent diseases as it is estimated to save over 3 million lives every year. However, the full potential of global immunization programs is not realised because population coverage is still suboptimal. This is also due to the inadequate immune response and paucity of informative correlates of protection upon immunization of vulnerable individuals such as newborns, preterm infants, pregnant women, and elderly individuals as well as those patients affected by chronic and immune compromising medical conditions. In addition, these groups are undervaccinated for a number of reasons, including lack of awareness of vaccine-preventable diseases and uncertainty or misconceptions about the safety and efficacy of vaccination by parents and healthcare providers. The presence of these nonresponders/undervaccinated individuals represents a major health and economic burden to society, which will become particularly difficult to address in settings with limited public resources. This review describes innovative and experimental approaches that can help identify specific genomic profiles defining nonresponder individuals for whom specific interventions might be needed. We will provide examples that show how such information can be useful to identify novel biomarkers of safety and immunogenicity for future vaccine trials. Finally, we will discuss how system biology “OMICs” data can be used to design bioinformatic tools to predict the vaccination outcome providing genetic and molecular “signatures” of protective immune response. This strategy may soon enable identification of signatures highly predictive of vaccine safety, immunogenicity, and efficacy/protection thereby informing personalized vaccine interventions in vulnerable populations.

Reduced immunity to measles in adults with major depressive disorder

BACKGROUND

Depression can impair the immunogenicity of vaccine administration in adults. Whereas many vaccinations are administered in childhood, it is not known whether adolescent or adult onset depression is associated with impairments in the maintenance of protection of childhood vaccines. This study tested the hypothesis that individuals with adolescent or adult onset mood disorders would display compromised immunity to measles, a target of childhood vaccination.

METHODS

IgG antibodies to measles were quantified using a solid phase immunoassay in volunteers with bipolar disorder (BD, n = 64, mean age of onset = 16.6 ± 5.6), currently depressed individuals with major depressive disorder (cMDD, n = 85, mean age of onset = 17.9 ± 7.0), remitted individuals with a history of MDD (rMDD, n = 82, mean age of onset = 19.2 ± 8.6), and non-depressed comparison controls (HC, n = 202), all born after the introduction of the measles vaccine in the USA in 1963.

RESULTS

Relative to HC, both the cMDD group (p = 0.021, adjusted odds ratios (OR) = 0.47, confidence interval (CI) = 0.24-0.90), and the rMDD group (p = 0.038, adjusted OR = 0.50, CI = 0.26-0.97) were less likely to test seropositive for measles. Compared with unmedicated MDD participants, currently medicated MDD participants had a longer lifetime duration of illness and were less likely to test seropositive for measles.

CONCLUSIONS

Individuals with adolescent or adult onset MDD are less likely to test seropositive for measles. Because lower IgG titers are associated with increased risk of measles infection, MDD may increase the risk and severity of infection possibly because of impaired maintenance of vaccine-related protection from measles.

Current perspectives in assessing humoral immunity after measles vaccination

INTRODUCTION

Repeated measles outbreaks in countries with relatively high vaccine coverage are mainly due to failure to vaccinate and importation; however, cases in immunized individuals exist raising questions about suboptimal measles vaccine-induced humoral immunity and/or waning immunity in a low measles-exposure environment.

AREAS COVERED

The plaque reduction neutralization measurement of functional measles-specific antibodies correlates with protection is the gold standard in measles serology, but it does not assess cellular-immune or other parameters that may be associated with durable and/or protective immunity after vaccination. Additional correlates of protection and long-term immunity and new determinants/signatures of vaccine responsiveness such as specific CD46 and IFI44L genetic variants associated with neutralizing antibody titers after measles vaccination are under investigation. Current and future systems biology studies, coupled with new technology/assays and analytical approaches, will lead to an increasingly sophisticated understanding of measles vaccine-induced humoral immunity and will identify 'signatures' of protective and durable immune responses.

EXPERT OPINION

This will translate into the development of highly predictive assays of measles vaccine efficacy, effectiveness, and durability for prospective identification of potential low/non-responders and susceptible individuals who require additional vaccine doses. Such new advances may drive insights into the development of new/improved vaccine formulations and delivery systems.

Incomplete vaccination coverage in European children with end-stage kidney disease prior to renal transplantation

BACKGROUND

Because infections constitute a major cause of morbidity and mortality in paediatric renal allograft recipients, avoidance of preventable systemic infections by vaccination before transplantation is of utmost importance. However, data on the completeness of vaccinations and factors associated with incomplete vaccination coverage are scarce.

METHODS

Within the framework of the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN), we therefore performed a multi-centre, multi-national, retrospective study investigating the vaccination coverage before transplantation of 254 European children with end-stage renal disease (mean age 10.0 ± 5.6 years).

RESULTS

Only 22 out of 254 patients (8.7%) presented complete vaccination coverage. In particular, the respective vaccination coverage against human papillomavirus (27.3%), pneumococci (42.0%), and meningococci (47.9%) was low. Patients with complete pneumococcal vaccination coverage had numerically less lower respiratory tract infections during the first 3 years post-transplant than children without vaccination or with an incomplete status (16.4% vs 27.7%, p = 0.081). Vaccine-preventable diseases post-transplant were 4.0 times more frequently in unvaccinated than in vaccinated patients. Factors associated with an incomplete vaccination coverage were non-Caucasian ethnicity (OR 9.21, p = 0.004), chronic dialysis treatment before transplantation (OR 6.18, p = 0.001), and older age at transplantation (OR 1.33, p < 0.001).

CONCLUSIONS

The vaccination coverage in paediatric kidney transplant candidates is incomplete. Paediatric nephrologists, together with primary-care staff and patients' families, should therefore make every effort to improve vaccination rates before kidney transplantation.