Rheumatic Fever and Rheumatic Heart Disease in the United States

Emergent emm4 group A Streptococcus evidences a survival strategy during interaction with immune effector cells

The major gram-positive pathogen group A Streptococcus (GAS) is a model organism for studying microbial epidemics as it causes waves of infections. Since 1980, several GAS epidemics have been ascribed to the emergence of clones producing increased amounts of key virulence factors such as streptolysin O (SLO). Herein, we sought to identify mechanisms underlying our recently identified temporal clonal emergence among emm4 GAS, given that emergent strains did not produce augmented levels of virulence factors relative to historic isolates. By creating and analyzing isoallelic strains, we determined that a conserved mutation in a previously undescribed gene encoding a putative carbonic anhydrase was responsible for the defective in vitro growth observed in the emergent strains. We also identified that the emergent strains survived better inside macrophages and killed macrophages at lower rates than the historic strains. Via the creation of isogenic mutant strains, we linked the emergent strain "survival" phenotype to the downregulation of the SLO encoding gene and upregulation of the msrAB operon which encodes proteins involved in defense against extracellular oxidative stress. Our findings are in accord with recent surveillance studies which found a high ratio of mucosal (i.e., pharyngeal) relative to invasive infections among emm4 GAS. Since ever-increasing virulence is unlikely to be evolutionarily advantageous for a microbial pathogen, our data further understanding of the well-described oscillating patterns of virulent GAS infections by demonstrating mechanisms by which emergent strains adapt a "survival" strategy to outcompete previously circulating isolates.

Long COVID: Alice Evans, Brucellosis, and Reflections on Infectious Causes of Chronic Disease

Despite more than a century of research on the link between infection and chronic diseases, we again find ourselves flummoxed by a new pathogen that causes long-term impairment. Patients have reported being ignored or minimized, resources are lacking for diagnosis and treatment, and frustrated individuals are turning outside of the scientific profession for answers. The experience mirrors that of American Society for Microbiology past president Alice C. Evans. Accidentally infected with Brucella melitensis during her laboratory research, Evans was chronically ill for more than 20 years, during which time friends, colleagues, and physicians cast doubt on her illness. As a result, she argued passionately for improved diagnostics and for those who reported chronic infection to be taken seriously rather than presumed to be "malingering" or using their illness for financial benefit. Lessons from Evans' experience are useful as we work toward understanding long COVID and patients suffering from the condition.

Identifying genetic determinants of Streptococcus pyogenes-host interactions in a murine intact skin infection model

Streptococcus pyogenes is an obligate human pathobiont associated with many disease states. Here, we present a model of S. pyogenes infection using intact murine epithelium. We were able to perform RNA sequencing to evaluate genetic changes undertaken by both the bacterium and host at 5 and 24 h post-infection. Analysis of these genomic data demonstrate that S. pyogenes undergoes genetic adaptation to successfully infect the murine epithelium, including changes to metabolism and activation of the Rgg2/Rgg3 quorum-sensing (QS) system. Subsequent experiments demonstrate that an intact Rgg2/Rgg3 QS cascade is necessary to establish a stable superficial skin infection. QS cascade activation results in increased murine morbidity and bacterial burden on the skin. This phenotype is associated with gross changes to the murine skin and with evidence of inflammation. These experiments offer a method to investigate S. pyogenes-epithelial interactions and demonstrate that a well-studied QS pathway is critical to a persistent infection.

Research priorities for the primordial prevention of acute rheumatic fever and rheumatic heart disease by modifying the social determinants of health

The social determinants of health (SDH), such as access to income, education, housing and healthcare, strongly shape the occurrence of acute rheumatic fever (ARF) and rheumatic heart disease (RHD) at the household, community and national levels. The SDH are systemic factors that privilege some more than others and result in poverty and inequitable access to resources to support health and well-being. Primordial prevention is the modification of SDH to improve health and reduce the risk of disease acquisition and the subsequent progression to RHD. Modifying these determinants using primordial prevention strategies can reduce the risk of exposure to Group A Streptococcus, a causative agent of throat and skin infections, thereby lowering the risk of initiating ARF and its subsequent progression to RHD.This report summarises the findings of the Primordial Prevention Working Group-SDH, which was convened in November 2021 by the National Heart, Lung, and Blood Institute to assess how SDH influence the risk of developing RHD. Working group members identified a series of knowledge gaps and proposed research priorities, while recognising that community engagement and partnerships with those with lived experience will be integral to the success of these activities. Specifically, members emphasised the need for: (1) global analysis of disease incidence, prevalence and SDH characteristics concurrently to inform policy and interventions, (2) global assessment of legacy primordial prevention programmes to help inform the co-design of interventions alongside affected communities, (3) research to develop, implement and evaluate scalable primordial prevention interventions in diverse settings and (4) research to improve access to and equity of services across the RHD continuum. Addressing SDH, through the implementation of primordial prevention strategies, could have broader implications, not only improving RHD-related health outcomes but also impacting other neglected diseases in low-resource settings.

IgG2 rules: N-acetyl-β-D-glucosamine-specific IgG2 and Th17/Th1 cooperation may promote the pathogenesis of acute rheumatic heart disease and be a biomarker of the autoimmune sequelae of Streptococcus pyogenes

Antecedent group A streptococcal pharyngitis is a well-established cause of acute rheumatic fever (ARF) where rheumatic valvular heart disease (RHD) and Sydenham chorea (SC) are major manifestations. In ARF, crossreactive antibodies and T cells respond to streptococcal antigens, group A carbohydrate, N-acetyl-β-D-glucosamine (GlcNAc), and M protein, respectively, and through molecular mimicry target heart and brain tissues. In this translational human study, we further address our hypothesis regarding specific pathogenic humoral and cellular immune mechanisms leading to streptococcal sequelae in a small pilot study. The aims of the study were to (1) better understand specific mechanisms of pathogenesis in ARF, (2) identify a potential early biomarker of ARF, (3) determine immunoglobulin G (IgG) subclasses directed against GlcNAc, the immunodominant epitope of the group A carbohydrate, by reaction of ARF serum IgG with GlcNAc, M protein, and human neuronal cells (SK-N-SH), and (4) determine IgG subclasses deposited on heart tissues from RHD. In 10 pediatric patients with RHD and 6 pediatric patients with SC, the serum IgG2 subclass reacted significantly with GlcNAc, and distinguished ARF from 7 pediatric patients with uncomplicated pharyngitis. Three pediatric patients who demonstrated only polymigrating arthritis, a major manifestation of ARF and part of the Jones criteria for diagnosis, lacked the elevated IgG2 subclass GlcNAc-specific reactivity. In SC, the GlcNAc-specific IgG2 subclass in cerebrospinal fluid (CSF) selectively targeted human neuronal cells as well as GlcNAc in the ELISA. In rheumatic carditis, the IgG2 subclass preferentially and strongly deposited in valve tissues (n = 4) despite elevated concentrations of IgG1 and IgG3 in RHD sera as detected by ELISA to group A streptococcal M protein. Although our human study of ARF includes a very small limited sample set, our novel research findings suggest a strong IgG2 autoantibody response against GlcNAc in RHD and SC, which targeted heart valves and neuronal cells. Cardiac IgG2 deposition was identified with an associated IL-17A/IFN-γ cooperative signature in RHD tissue which displayed both IgG2 deposition and cellular infiltrates demonstrating these cytokines simultaneously. GlcNAc-specific IgG2 may be an important autoantibody in initial stages of the pathogenesis of group A streptococcal sequelae, and future studies will determine if it can serve as a biomarker for risk of RHD and SC or early diagnosis of ARF.

The projections of global and regional rheumatic heart disease burden from 2020 to 2030

Background

Rheumatic heart disease (RHD) remains the leading cause of preventable death and disability in children and young adults, killing an estimated 320,000 individuals worldwide yearly.

Materials and methods

We utilized the Bayesian age-period cohort (BAPC) model to project the change in disease burden from 2020 to 2030 using the data from the Global Burden of Disease (GBD) Study 2019. Then we described the projected epidemiological characteristics of RHD by region, sex, and age.

Results

The global age-standardized prevalence rate (ASPR) and age-standardized incidence rate (ASIR) of RHD increased from 1990 to 2019, and ASPR will increase to 559.88 per 100,000 population by 2030. The global age-standardized mortality rate (ASMR) of RHD will continue declining, while the projected death cases will increase. Furthermore, ASPR and cases of RHD-associated HF will continue rising, and there will be 2,922,840 heart failure (HF) cases in 2030 globally. Female subjects will still be the dominant population compared to male subjects, and the ASPR of RHD and the ASPR of RHD-associated HF in female subjects will continue to increase from 2020 to 2030. Young people will have the highest ASPR of RHD among all age groups globally, while the elderly will bear a greater death and HF burden.

Conclusion

In the following decade, the RHD burden will remain severe. There are large variations in the trend of RHD burden by region, sex, and age. Targeted and effective strategies are needed for the management of RHD, particularly in female subjects and young people in developing regions.

Psychopathological Impact in Patients with History of Rheumatic Fever with or without Sydenham's Chorea: A Multicenter Prospective Study

Sydenham's chorea (SC) is a post-streptococcal autoimmune disorder of the central nervous system, and it is a major criterium for the diagnosis of acute rheumatic fever (ARF). SC typically improves in 12-15 weeks, but patients can be affected for years by persistence and recurrencies of both neurological and neuropsychiatric symptoms. We enrolled 48 patients with a previous diagnosis of ARF, with or without SC, in a national multicenter prospective study, to evaluate the presence of neuropsychiatric symptoms several years after SC's onset. Our population was divided in a SC group (n = 21), consisting of patients who had SC, and a nSC group (n = 27), consisting of patients who had ARF without SC. Both groups were evaluated by the administration of 8 different neuropsychiatric tests. The Work and Social Adjustment Scale (WSAS) showed significantly (p = 0.021) higher alterations in the SC group than in the nSC group. Furthermore, 60.4% (n = 29) of the overall population experienced neuropsychiatric symptoms other than choreic movements at diagnosis and this finding was significantly more common (p = 0.00) in SC patients (95.2%) than in nSC patients (33.3%). The other neuropsychiatric tests also produced significant results, indicating that SC can exert a strong psychopathological impact on patients even years after its onset.

Cardiac Sequelae of COVID-19 in Children and Young Adults

Coronavirus disease 2019 (COVID-19) has a predilection to cardiac involvement. The early clinical phase, during viremia, may manifest as pericarditis, acute myocarditis, and sepsis-related cardiomyopathy. Delayed presentations, such as multisystem inflammatory syndrome in children, coronary artery dilation/aneurysms, and late myocarditis, may occur in the weeks after the acute infection. These delayed presentations commonly test negative for severe acute respiratory syndrome coronavirus 2 via polymerase chain reaction testing and are thought to be primarily postviral hyperinflammatory sequelae. The long-term consequences of cardiac involvement in COVID-19 are unknown. Most recommendations for cardiac management are based on known conditions that are similar. For example, coronary aneurysms can be managed under Kawasaki disease guidelines. Similarly, for patients with COVID-19 myocarditis, they can be cleared for sports under protocols for other types of myocarditis. There is concern for cardiac involvement as a subclinical entity even in more minor presentations. Several expert algorithms have been developed for clearing competition athletes to return to exercise. Sports clearance should be individualized considering the severity of disease, age of patient, and performance level of the sport. [Pediatr Ann. 2021;50(3):e128-e135.].