Epigenetic profiling linked to multisystem inflammatory syndrome in children (MIS-C): A multicenter, retrospective study

FCGR2A Gene Polymorphism Association in Children with Multisystem Inflammatory Syndrome

OBJECTIVE

Fc gamma receptor IIa (FCGR2A) gene polymorphism is associated with increased susceptibility to autoimmune and infectious diseases. The aim of the present study was to evaluate the association of FCGR2A rs1801274 polymorphism with the development and severity of multisystem inflammatory syndrome in children (MIS-C).

METHODS

This case-control study was conducted in a single center with MIS-C patients and healthy children. Clinical and cardiac imaging data of the participants was collected. The association between the clinical severity of the disease and FCGR2A rs1801274 polymorphism were investigated.

RESULTS

There was no significant association between FCGR2A rs1801274 polymorphism and cardiovascular complications in MIS-C patients. However, those with homozygous FCGR2A rs1801274 gene polymorphism developed severe cardiac dysfunction and required immunomodulatory agents other than intravenous immunoglobulin. The mean age of the patients with severe MIS-C was significantly higher than those with mild MIS-C, and systolic dysfunction was significant.

CONCLUSIONS

Further multicenter studies in different ethnic groups are needed to evaluate the association between differences in the FCGR2A rs1801274 gene and severity of MIS-C and/or other inflammatory diseases.

TRIAL REGISTRY

Mersin University Clinical Trial Registry, Decision number 2022/280 dated April 20, 2022.

A SuperLearner-based pipeline for the development of DNA methylation-derived predictors of phenotypic traits

BACKGROUND

DNA methylation (DNAm) provides a window to characterize the impacts of environmental exposures and the biological aging process. Epigenetic clocks are often trained on DNAm using penalized regression of CpG sites, but recent evidence suggests potential benefits of training epigenetic predictors on principal components.

METHODOLOGY/FINDINGS

We developed a pipeline to simultaneously train three epigenetic predictors; a traditional CpG Clock, a PCA Clock, and a SuperLearner PCA Clock (SL PCA). We gathered publicly available DNAm datasets to generate i) a novel childhood epigenetic clock, ii) a reconstructed Hannum adult blood clock, and iii) as a proof of concept, a predictor of polybrominated biphenyl exposure using the three developmental methodologies. We used correlation coefficients and median absolute error to assess fit between predicted and observed measures, as well as agreement between duplicates. The SL PCA clocks improved fit with observed phenotypes relative to the PCA clocks or CpG clocks across several datasets. We found evidence for higher agreement between duplicate samples run on alternate DNAm arrays when using SL PCA clocks relative to traditional methods. Analyses examining associations between relevant exposures and epigenetic age acceleration (EAA) produced more precise effect estimates when using predictions derived from SL PCA clocks.

CONCLUSIONS

We introduce a novel method for the development of DNAm-based predictors that combines the improved reliability conferred by training on principal components with advanced ensemble-based machine learning. Coupling SuperLearner with PCA in the predictor development process may be especially relevant for studies with longitudinal designs utilizing multiple array types, as well as for the development of predictors of more complex phenotypic traits.

An Update on Multi-System Inflammatory Syndrome in Children

PURPOSE

To summarize the latest research on the epidemiology, pathogenesis, diagnosis, and treatment of multisystem inflammatory syndrome in children (MIS-C).

RECENT FINDINGS

The epidemiology of MIS-C has been dynamic since its initial description. The pathogenesis remains poorly understood. Case definitions of MIS-C have evolved over time, and practice patterns for treating MIS-C are variable with generally positive long-term outcomes yet persistent changes noted. MIS-C has become less prevalent and less severe over time, yet racial and ethnic disparities persist, and vaccination against COVID-19 is highly effective in preventing this disease. The link between acute infection and subsequent inflammation is not well understood, with growing evidence describing its immunologic signature. Newer case definitions require excluding other inflammatory conditions, including Kawasaki Disease (KD), before diagnosing MIS-C. Corticosteroid monotherapy may be non-inferior to IVIg alone or combination IVIg plus corticosteroids for initial treatment, distinguishing the approaches to MIS-C and KD. A wide range of biologic therapies have been employed for rescue therapy with general success and no clear benefit of one over another. Despite reports of a high rate of coronary artery abnormality regression and resolution of heart failure, long-term studies suggest persistent changes to cardiac function. The long-term effects of MIS-C continue to be active areas of research.

Genetic insights into MIS-C Post-COVID-19 in Kuwaiti children: investigating monogenic factors

Background

Multisystem inflammatory syndrome in children (MIS-C) is a severe complication arising from SARS-CoV-2 infection, with indications that rare inborn errors of immunity may play a role in its pathogenesis. Recent studies suggest that genetic predispositions, particularly monogenic forms, could significantly influence the immune responses to SARS-CoV-2 in MIS-C.

Methods

We analysed 24 children under 12 years old, all of whom met the criteria provided by the World Health Organization, 2020 for MIS-C diagnosis, from the Paediatric COVID-19 Registry in Kuwait (PCR-Q8). Demographic and clinical data were collected from medical records, and exome sequencing was performed on the children and their parents to identify rare exonic variants. These variants were prioritized using two approaches: a candidate genes approach employing trio segregation analysis, and a candidate variants approach using a gene panel informed by previous studies on MIS-C-related genetic variants and datasets of differentially expressed genes in MIS-C patients.

Results

The candidate genes approach identified 53 unique genes in 20 of the 24 probands, including DDX60 and TMEM154, which were also differentially expressed between MIS-C and control groups. The candidate variants approach identified 33 rare, predicted deleterious heterozygous variants across 19 unique genes in 19 of the 24 probands, including both previously described and novel candidate variants for MIS-C. Pathway analysis of the identified genes from both approaches revealed significant involvement in immune response, viral defence, and inflammatory pathways.

Conclusion

This study underscores the monogenic susceptibility to MIS-C, enhancing the evidence base through comprehensive genetic analysis. The findings highlight the critical role of genetic predispositions in MIS-C and suggest that further functional genomics work is necessary to explore the mechanistic contributions of these genes, facilitating the development of targeted diagnostic strategies.

Acute hepatitis of unknown aetiology in children: evidence for and against causal relationships with SARS-CoV-2, HAdv and AAV2

BACKGROUND

The cause of acute paediatric hepatitis of unknown aetiology (2022) has not been established despite extensive investigation.

OBJECTIVE

To summarise the evidence for and against a causal role for human adenovirus (HAdv), adeno-associated virus 2 (AAV-2) and SARS-CoV-2 in outbreaks of paediatric hepatitis in 2022.

METHODS

We appraised and summarised relevant evidence for each of the Bradford Hill criteria for causality using quantitative (statistical modelling) and qualitative (narrative coherence) approaches. Each team member scored the evidence base for each criterion separately for HAdv, AAV-2 and SARS-CoV-2; differences were resolved by discussion. We additionally examined criteria of strength and temporality by examining the lagged association between SARS-CoV-2 positivity, respiratory HAdv positivity, positive faecal HAdv specimens and excess A&E attendances in 1-4 years for liver conditions in England.

RESULTS

Assessing criteria using the published literature and our modelling: for HAdv three Bradford Hill criteria (strength, consistency and temporality) were partially met; and five criteria (consistency, coherence, experimental manipulation, analogy and temporality) were minimally met. For AAV-2, the strength of association criterion was fully met, five criteria (consistency, temporality, specificity, biological gradient and plausibility) were partially met and three (coherence, analogy and experimental manipulation) were minimally met. For SARS-CoV-2, five criteria (strength of association, plausibility, temporality, coherence and analogy) were fully met; one (consistency) was partially met and three (specificity, biological gradient and experimental manipulation) were minimally met.

CONCLUSION

Based on the Bradford Hill criteria and modelling, HAdv alone is unlikely to be the cause of the recent increase in hepatitis in children. The causal link between SARS-CoV-2, and to a lesser degree AAV-2, appears substantially stronger but remains unproven. Hepatitis is a known complication of multisystem inflammatory syndrome in children following COVID-19, and SARS-CoV-2 has been linked to increased susceptibility to infection post-COVID-19, which may suggest complex causal pathways including a possible interaction with AAV-2 infection/reactivation in hosts that are genetically susceptible or sensitised to infection.

Development of an epigenetic clock resistant to changes in immune cell composition

Epigenetic clocks are age predictors that use machine-learning models trained on DNA CpG methylation values to predict chronological or biological age. Increases in predicted epigenetic age relative to chronological age (epigenetic age acceleration) are connected to aging-associated pathologies, and changes in epigenetic age are linked to canonical aging hallmarks. However, epigenetic clocks rely on training data from bulk tissues whose cellular composition changes with age. Here, we found that human naive CD8+ T cells, which decrease in frequency during aging, exhibit an epigenetic age 15-20 years younger than effector memory CD8+ T cells from the same individual. Importantly, homogenous naive T cells isolated from individuals of different ages show a progressive increase in epigenetic age, indicating that current epigenetic clocks measure two independent variables, aging and immune cell composition. To isolate the age-associated cell intrinsic changes, we created an epigenetic clock, the IntrinClock, that did not change among 10 immune cell types tested. IntrinClock shows a robust predicted epigenetic age increase in a model of replicative senescence in vitro and age reversal during OSKM-mediated reprogramming.

Clinical and Laboratory Biomarkers as Predictors of Severity in Pediatric Inflammatory Multisystem Syndrome-temporally Associated With SARS-CoV-2: Data From a Prospective Nationwide Surveillance Study in Switzerland

BACKGROUND

PIMS-TS (pediatric inflammatory multisystem syndrome-temporally associated with SARS-CoV-2) is a rare but serious condition in children following SARS-CoV-2 infection, characterized by a range of clinical symptoms with varying severity. Understanding risk factors for severe PIMS-TS is crucial for appropriate and timely intervention.

OBJECTIVE

To identify factors associated with increased PIMS-TS severity in children.

METHODS

In this nationwide prospective observational study, epidemiological and clinical data was collected from children <18 years of age with suspected or confirmed PIMS-TS from all 29 pediatric hospitals in Switzerland. Children were categorized into 3 groups according to admission to intensive care unit (ICU): non-ICU, ICU-moderate and ICU-severe, defined as requirement of invasive ventilation and/or inotropic support.

RESULTS

A total of 204 children were included; 99 (49%) were categorized as non-ICU, 50 (25%) as ICU-moderate and 55 (27%) as ICU-severe. In ICU-severe cases, respiratory and neurological symptoms were more frequent compared with non-ICU cases: 72% versus 47%, P < 0.001 and 66% versus 41%, P = 0.001, respectively. Compared with the non-ICU group, children in the ICU-severe group had lower lymphocyte counts, higher neutrophil-lymphocyte ratios, lower platelet counts, as well as higher C-reactive protein, N-terminal pro-B-type natriuretic peptide, troponin T and creatinine levels at admission. Lymphopenia and elevated troponin T levels at admission were associated with an increased risk of being in the ICU-severe group.

CONCLUSION

The severity of PIMS-TS may be predicted using clinical symptoms and laboratory biomarkers, which help clinicians in decision-making and management of patients.

The Initial COVID-19 Reliable Interactive DNA Methylation Markers and Biological Implications

Earlier research has established the existence of reliable interactive genomic biomarkers. However, reliable DNA methylation biomarkers, not to mention interactivity, have yet to be identified at the epigenetic level. This study, drawing from 865,859 methylation sites, discovered two miniature sets of Infinium MethylationEPIC sites, each having eight CpG sites (genes) to interact with each other and disease subtypes. They led to the nearly perfect (96.87-100% accuracy) prediction of COVID-19 patients from patients with other diseases or healthy controls. These CpG sites can jointly explain some post-COVID-19-related conditions. These CpG sites and the optimally performing genomic biomarkers reported in the literature become potential druggable targets. Among these CpG sites, cg16785077 (gene MX1), cg25932713 (gene PARP9), and cg22930808 (gene PARP9) at DNA methylation levels indicate that the initial SARS-CoV-2 virus may be better treated as a transcribed viral DNA into RNA virus, i.e., not as an RNA virus that has concerned scientists in the field. Such a discovery can significantly change the scientific thinking and knowledge of viruses.

Epigenetic biomarkers for disease susceptibility and preventative medicine

The development of molecular biomarkers for disease makes it possible for preventative medicine approaches to be considered. Therefore, therapeutics, treatments, or clinical management can be used to delay or prevent disease development. The problem with genetic mutations as biomarkers is the low frequency with genome-wide association studies (GWASs), generally at best a 1% association of the patients with the disease. In contrast, epigenetic alterations have a high-frequency association of greater than 90%-95% of individuals with pathology in epigenome-wide association studies (EWASs). A wide variety of human diseases have been shown to have epigenetic biomarkers that are disease specific and that detect pathology susceptibility. This review is focused on the epigenetic biomarkers for disease susceptibility, and it distinct from the large literature on epigenetics of disease etiology or progression. The development of efficient epigenetic biomarkers for disease susceptibility will facilitate a paradigm shift from reactionary medicine to preventative medicine.

Association of SARS-CoV-2 infection with neurological impairments in pediatric population: A systematic review

Neurological manifestations have been widely reported in adults with COVID-19, yet the extent of involvement among the pediatric population is currently poorly characterized. The objective of our systematic review is to evaluate the association of SARS-CoV-2 infection with neurological symptoms and neuroimaging manifestations in the pediatric population. A literature search of Cochrane Library; EBSCO CINAHL; Global Index Medicus; OVID AMED, Embase, Medline, PsychINFO; and Scopus was conducted in accordance with the Peer Review of Electronic Search Strategies form (October 1, 2019 to March 15, 2022). Studies were included if they reported (1) COVID-19-associated neurological symptoms and neuroimaging manifestations in individuals aged <18 years with a confirmed, first SARS-CoV-2 infection and were (2) peer-reviewed. Full-text reviews of 222 retrieved articles were performed, along with subsequent reference searches. A total of 843 no-duplicate records were retrieved. Of the 19 identified studies, there were ten retrospective observational studies, seven case series, one case report, and one prospective cohort study. A total of 6985 individuals were included, where 12.8% (n = 892) of hospitalized patients experienced neurocognitive impairments which includes: 1) neurological symptoms (n = 294 of 892, 33.0%), 2) neurological syndromes and neuroimaging abnormalities (n = 223 of 892, 25.0%), and 3) other phenomena (n = 233 of 892, 26.1%). Based on pediatric-specific cohorts, children experienced more drowsiness (7.3% vs. 1.3%) and muscle weakness (7.3% vs. 6.3%) as opposed to adolescents. Agitation or irritability was observed more in children (7.3%) than infants (1.3%). Our findings revealed a high prevalence of immune-mediated patterns of disease among COVID-19 positive pediatric patients with neurocognitive abnormalities.

Mutations in VWA8 cause autosomal-dominant retinitis pigmentosa via aberrant mitophagy activation

BACKGROUND

Although retinitis pigmentosa (RP) is the most common type of hereditary retinal dystrophy, approximately 25%-45% of cases remain without a molecular diagnosis. von Willebrand factor A domain containing 8 (VWA8) encodes a mitochondrial matrix-targeted protein; its molecular function and pathogenic mechanism in RP remain unexplained.

METHODS

Family members of patients with RP underwent ophthalmic examinations, and peripheral blood samples were collected for exome sequencing, ophthalmic targeted sequencing panel and Sanger sequencing. The importance of VWA8 in retinal development was demonstrated by a zebrafish knockdown model and cellular and molecular analysis.

RESULTS

This study recruited a Chinese family of 24 individuals with autosomal-dominant RP and conducted detailed ophthalmic examinations. Exome sequencing analysis of six patients revealed heterozygous variants in VWA8, namely, the missense variant c.3070G>A (p.Gly1024Arg) and nonsense c.4558C>T (p.Arg1520Ter). Furthermore, VWA8 expression was significantly decreased both at the mRNA and protein levels. The phenotypes of zebrafish with VWA8 knockdown are similar to those of clinical individuals harbouring VWA8 variants. Moreover, VWA8 defects led to severe mitochondrial damage, resulting in excessive mitophagy and the activation of apoptosis.

CONCLUSIONS

VWA8 plays a significant role in retinal development and visual function. This finding may provide new insights into RP pathogenesis and potential genes for molecular diagnosis and targeted therapy.

Multisystem inflammatory syndrome in children: A dysregulated autoimmune disorder following COVID-19

Multisystem inflammatory syndrome in children (MIS-C) is a dysregulated autoimmune-mediated illness in genetically susceptible patients following COVID-19 with an interval of 2-6 weeks. The median age of patients with MIS-C is 6-11 years. Most common manifestations are involvement of gastrointestinal tract, cardiovascular system, hematological system, and mucocutaneous system. Respiratory tract, neurological system, musculoskeletal system, and kidney are less frequently affected. Mucocutaneous manifestations and coronary artery abnormalities characteristic for Kawasaki disease (KD) may be observed in a significant proportion of MIS-C patients that may make the differential diagnosis be difficult for some patients, especially in the post-pandemic era. The mortality rate is 1-3%. Management and prognosis of MIS-C are similar to that of KD. MIS-C and KD may share a common pathogenic process. Based on the observation of MIS-C-like illness in uninfected neonates, i.e. multisystem inflammatory syndrome in neonates, both MIS-C and KD may be a consequence of dysregulated, over-exaggerated humoral immune responses triggered by a specific infectious agent.

Association of SARS-CoV-2 Infection with Neurological Symptoms and Neuroimaging Manifestations in the Pediatric Population: A Systematic Review

Background

Neurological manifestations have been widely reported in adults with COVID-19, yet the extent of involvement among the pediatric population is currently poorly characterized. The objective of our systematic review is to evaluate the association of SARS-CoV-2 infection with neurological symptoms and neuroimaging manifestations in the pediatric population.

Methods

A literature search of Cochrane Library; EBSCO CINAHL; Global Index Medicus; OVID AMED, Embase, Medline, PsychINFO; and Scopus was conducted in accordance with the Peer Review of Electronic Search Strategies form (October 1, 2019 to March 15, 2022). Studies were included if they reported (1) COVID-19-associated neurological symptoms and neuroimaging manifestations in individuals aged < 18 years with a confirmed, first SARS-CoV-2 infection and were (2) peer-reviewed. Full-text reviews of 222 retrieved articles were performed, along with subsequent reference searches.

Results

A total of 843 nonduplicate records were retrieved. Of the 19 identified studies, there were ten retrospective observational studies, seven case series, one case report, and one prospective cohort study. A total of 6,985 individuals were included, where 12.8% of hospitalized patients experienced neurocognitive impairments: MIS-C (24.2%), neuroinflammation (10.1%), and encephalopathy (8.1%) were the most common disorders; headaches (16.8%) and seizures (3.8%) were the most common symptoms. Based on pediatric-specific cohorts, children experienced more drowsiness (7.3% vs. 1.3%) and muscle weakness (7.3% vs. 6.3%) as opposed to adolescents. Agitation or irritability was observed more in children (7.3%) than infants (1.3%).

Conclusion

Our findings revealed a high prevalence of immune-mediated patterns of disease among COVID-19 positive pediatric patients with neurocognitive abnormalities.

Multisystem inflammatory syndrome in neonates (MIS-N): a systematic review

Recently, a new pattern of multisystem inflammatory syndrome following an infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has emerged globally. The initial cases were described in the adult population followed by sporadic cases in the pediatric population also. By the end of 2020, similar reports were recognised in the neonatal age group. The purpose of this study was to systematically review clinical characteristics, laboratory parameters, treatment, and outcomes of neonates with multisystem inflammatory syndrome in neonates (MIS-N). A systematic review was conducted after registering with PROSPERO and electronic databases including MEDLINE, EMBASE, PubMed, SCOPUS, Google Scholar, and Web of Science were searched from January 1st 2020 till September 30th 2022. A total of 27 studies describing 104 neonates were analysed. The mean gestation age and birth weight was 35.9 ± 3.3 weeks and 2255.7 ± 783.7 g respectively. A large proportion (91.3%) of the reported cases belonged to the South-East Asian region. The median age of presentation was 2 days (range: 1-28 days) with cardiovascular system being the predominant system involved in 83.65% followed by respiratory (64.42%). Fever was noted in only 20.2%. Commonly elevated inflammatory markers were IL-6 in 86.7% and D-dimer in 81.1%. Echocardiographic evaluation suggested ventricular dysfunction in 35.8% and dilated coronary arteries in 28.3%. Evidence of SARS-CoV-2 antibodies (IgG or IgM) was seen in 95.9% neonates and evidence of maternal SARS-CoV-2 infection, either as history of COVID infection or positive antigen or antibody test, was noted in 100% of the cases. Early MIS-N was reported in 58 (55.8%) cases, late MIS-N in 28 (26.9%), and 18 cases (17.3%) did not report the timing of presentation. There was a statistically increased proportion of preterm infants (67.2%, p < 0.001), and a trend towards increased low birth weight infants, in the early MIS-N group when compared to the infants with late MIS-N. Fever (39.3%), central nervous system (50%), and gastrointestinal manifestations (57.1%) were significantly higher in the late MIS-N group (p = 0.03, 0.02, 0.01 respectively). The anti-inflammatory agents used for the treatment of MIS-N included steroids 80.8% which were given for a median of 10 (range 3-35) days and IVIg in 79.2% with a median of 2 (range 1-5) doses. The outcomes were available for 98 cases, of whom 8 (8.2%) died during treatment in hospital and 90 (91.8%) were successfully discharged home.   Conclusion: MIS-N has a predilection for late preterm males with predominant cardiovascular involvement. The diagnosis is challenging in neonatal period due to overlap with neonatal morbidities and a high risk of suspicion is warranted, especially in presence of supportive maternal and neonatal clinical history. The major limitation of the review was inclusion of case reports and case series, and highlights need of global registries for MIS-N. What is Known: • A new pattern of multisystem inflammatory syndrome following SARS-CoV-2 infection has emerged in adult population with sporadic cases now being reported in neonates. What is New: • MIS-N is an emerging condition with a heterogeneous spectrum and has a predilection for late preterm male infants. Cardiovascular system is the predominant system involved  followed by respiratory, however fever remains an uncommon presentation unlike other age-groups. There are two subtypes based on timing of presentation, with early MIS-N being reported more in preterm and low-birth weight infants.