Corrigendum: IgG2 rules: N-acetyl-ß-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.

[This corrects the article DOI: 10.3389/fcvm.2022.919700.].

IgG2 rules: N-acetyl-ß-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-ß-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.

Impact of the Connected Medicine collaborative in improving access to specialist care: a cross-sectional analysis.

BACKGROUND: In 2017, the Canadian Foundation for Healthcare Improvement launched the Connected Medicine collaborative to support the implementation, spread and adaptation of 2 innovative remote consult solutions - the Champlain Building Access to Specialists through eConsultation (BASE) eConsult service and the Rapid Access to Consultative Expertise (RACE) service - across Canada. We evaluated the impact of the programs implemented through the collaborative. METHODS: We conducted a cross-sectional analysis of data from provincial teams that participated in the Connected Medicine collaborative, which took place between June 2017 and December 2018 in 7 provinces across Canada (British Columbia, Alberta, Saskatchewan, Manitoba, Quebec, New Brunswick, Newfoundland and Labrador). Data included utilization data collected automatically by the BASE and RACE services and, where available, responses to surveys completed by primary care providers at the end of each case. We assessed programs on the following outcomes: usage (i.e., number of cases completed, average specialist response time), number of specialties available, impact on primary care provider's decision to refer and impact on emergency department visits. We performed descriptive analyses. RESULTS: Ten provincial teams participated in the collaborative and implemented or adapted either the RACE service (4 teams), the BASE service (5 teams) or a combination of the 2 services (1 team). Average monthly case volume per team ranged from 14.7 to 424.5. All programs offered multispecialty access, with specialists from 5 to 37 specialty groups available. Specialists responded to eConsults within 7 days in 80% (n = 294/368) to 93% (n = 164/176) of cases. Six programs provided survey data on avoidance of referrals, which occurred in 48% (n = 667/1389) to 76% (n = 302/398) of cases. Two programs reported on the avoidance of potential emergency department visits, noting that originally considered referrals were avoided in 28% (n = 138/492) and 74% (n = 127/171) of cases, respectively. INTERPRETATION: The 2 innovative virtual care solutions implemented through the Connected Medicine collaborative received widespread usage and affected primary care providers' decisions to refer patients to specialists. The impact of these models of care in multiple settings shows that they are an effective means to move beyond the pilot stage and achieve spread and scale.

Triple Aim in Canada: developing capacity to lead to better health, care and cost.

QUALITY PROBLEM: Many modern health systems strive for 'Triple Aim' (TA)-better health for populations, improved experience of care for patients and lower costs of the system, but note challenges in implementation. Outcomes of applying TA as a quality improvement framework (QI) have started to be realized with early lessons as to why some systems make progress while others do not. INITIAL ASSESSMENT: Limited evidence is available as to how organizations create the capacity and infrastructure required to design, implement, evaluate and sustain TA systems. CHOICE OF SOLUTION: To support embedding TA across Canada, the Canadian Foundation for Healthcare Improvement supported enrolment of nine Canadian teams to participate in the Institute for Healthcare Improvement's TA Improvement Community. IMPLEMENTATION: Structured support for TA design, implementation, evaluation and sustainability was addressed in a collaborative programme of webinars and action periods. Teams were coached to undertake and test small-scale improvements before attempting to scale. EVALUATION: A summative evaluation of the Canadian cohort was undertaken to assess site progress in building TA infrastructure across various healthcare settings. The evaluation explored the process of change, experiences and challenges and strategies for continuous QI. LESSONS LEARNED: Delivering TA requires a sustained and coordinated effort supported by strong leadership and governance, continuous QI, engaged interdisciplinary teams and partnering within and beyond the healthcare sector.

Identification of streptococcal m-protein cardiopathogenic epitopes in experimental autoimmune valvulitis.

The M protein of rheumatogenic group A streptococci induces carditis and valvulitis in Lewis rats and may play a role in pathogenesis of rheumatic heart disease. To identify the epitopes of M5 protein that produce valvulitis, synthetic peptides spanning A, B, and C repeat regions contained within the extracellular domain of the streptococcal M5 protein were investigated. A repeat region peptides NT4, NT5/6, and NT7 induced valvulitis similar to the intact pepsin fragment of M5 protein. T cell lines from rats with valvulitis recognized M5 peptides NT5/6 and NT6. Passive transfer of an NT5/6-specific T cell line into naïve rats produced valvulitis characterized by infiltration of CD4+ cells and upregulation of VCAM-1, while an NT6-specific T cell line did not target the valve. Our new data suggests that M protein-specific T cells may be important mediators of valvulitis in the Lewis rat model of rheumatic carditis.

Tubulin is a neuronal target of autoantibodies in Sydenham's chorea.

Sydenham's chorea is a CNS disorder and sequela of group A streptococcal infection where deposition of Abs in brain may result in movement and neuropsychiatric abnormalities. We studied human mAbs 24.3.1, 31.1.1, and 37.2.1 derived from chorea and selected for cross-reactivity with group A streptococci and brain Ags. Our novel findings reveal that Sydenham's chorea mAbs target a 55-kDa brain protein with an N-terminal amino acid sequence of MREIVHLQ corresponding to beta-tubulin. Chorea mAb specificity for purified brain tubulin was confirmed in ELISA and Western immunoblot, and significant levels of anti-tubulin IgG were found in acute chorea sera and cerebrospinal fluid. Lysoganglioside G(M1) inhibited binding of chorea mAbs to tubulin and mAb reactivity with human caudate and putamen brain sections was blocked by anti-tubulin mAb. The chorea mAbs labeled both intra- and extracellular Ags of a neuronal cell line providing evidence suggesting mimicry between intracellular brain protein tubulin and extracellular lysoganglioside. In addition, chorea mAb 24.3.1 and acute chorea sera induced calcium/calmodulin-dependent protein kinase II activity in human neuronal cells. Nucleotide sequence analysis of the chorea mAb V(H) genes revealed that mAb 24.3.1 V(H) gene was encoded by the V(H)1 germline gene family which encodes other anti-ganglioside V(H) genes associated with motor neuropathies. mAb recognition of tubulin and the neuronal cell surface with initiation of cell signaling and dopamine release supports an emerging theme in autoimmunity whereby cross-reactive or polyreactive autoantibodies against intracellular Ags recognize cell surface epitopes potentially leading to disease.

Antibody-mediated neuronal cell signaling in behavior and movement disorders.

Behavioral and movement disorders may have antibody responses where mimicry and signal transduction may lead to neuropsychiatric abnormalities. In our study, antibodies in pediatric autoimmune neuropsychiatric disorders associated with streptococci (PANDAS) reacted with the neuronal cell surface and caudate-putamen and induced calcium-calmodulin dependent protein (CaM) kinase II activity in neuronal cells. Depletion of serum IgG abrogated CaM kinase II cell signaling and reactivity of CSF was blocked by streptococcal antigen N-acetyl-beta-d-glucosamine (GlcNAc). Antibodies against GlcNAc in PANDAS sera were inhibited by lysoganglioside G(M1). Results suggest that antibodies from an infection may signal neuronal cells in some behavioral and movement disorders.

Streptococcal mimicry and antibody-mediated cell signaling in the pathogenesis of Sydenham's chorea.

Recent evidence suggests that the pathogenesis of Sydenham's chorea following group A streptococcal infection is due to antibodies which develop due to the infection and infiltrate the brain and basal ganglia. Antibodies present in acute chorea react with the surface of neuronal cells and signal the induction of calcium calmodulin dependent protein kinase II with elevation of tyrosine hydroxylase and subsequent dopamine release which may lead to the movement disorder. The antibodies present in disease recognize lysoganglioside and the group A streptococcal epitope, N-acetyl-glucosamine. Monoclonal antibodies (mAbs) from Sydenham's chorea demonstrated the mimicry between lysoganglioside and the group A streptococcal carbohydrate epitope. A group of antibodies present in pediatric autoimmune neuropsychiatric disorders (PANDAS) were similar but not identical to the antibodies observed in chorea.

Mimicry and autoantibody-mediated neuronal cell signaling in Sydenham chorea.

Streptococcus pyogenes-induced acute rheumatic fever (ARF) is one of the best examples of postinfectious autoimmunity due to molecular mimicry between host and pathogen. Sydenham chorea is the major neurological manifestation of ARF but its pathogenesis has remained elusive, with no candidate autoantigen or mechanism of pathogenesis described. Chorea monoclonal antibodies showed specificity for mammalian lysoganglioside and N-acetyl-beta-D-glucosamine (GlcNAc), the dominant epitope of the group A streptococcal (GAS) carbohydrate. Chorea antibodies targeted the surface of human neuronal cells, with specific induction of calcium/calmodulin-dependent protein (CaM) kinase II activity by monoclonal antibody 24.3.1 and sera from active chorea. Convalescent sera and sera from other streptococcal diseases in the absence of chorea did not activate the kinase. The new evidence implicates antibody-mediated neuronal cell signaling in the immunopathogenesis of Sydenham chorea and will lead to a better understanding of other antibody-mediated neurological disorders.