Systematic Review of Group A Streptococcal emm Types Associated with Acute Post-Streptococcal Glomerulonephritis

Reduction in Acute Post-Streptococcal Glomerulonephritis Incidence in Counties Manukau, New Zealand, after the COVID-19 Pandemic

The COVID-19 pandemic has altered the epidemiology of many common childhood infections, including Group A streptococcal (GAS) disease. Acute post-streptococcal glomerulonephritis (APSGN) is a nonsuppurative complication of GAS pharyngitis and pyoderma. It remains the most common cause of pediatric acute glomerulonephritis globally. In Counties Manukau, New Zealand, APSGN rates have previously been shown to be the highest in the country, with marked ethnic and socioeconomic disparities. We performed a retrospective review of children aged 0-14 years who were discharged from Kidz First Hospital, Counties Manukau, between 2015 and 2023 and met the Strep A Vaccine Global Consortium consensus definition of APSGN. We describe a marked, sustained reduction in APSGN hospitalizations, temporally associated with the COVID-19 pandemic. This ongoing reduction in APSGN incidence is notable in light of contrasting reports of increasing incidence of rheumatic fever in New Zealand and invasive GAS disease internationally.

The heterophilicic epitopes in conserved HA regions of human and avian influenza viruses can produce antibodies that bound to kidney tissue

Influenza virus infection can cause kidney damage. However, the link between influenza infection and disease is still unclear. The purpose of this study was to analyze the relationship between heterophilic epitopes on H5N1 hemagglutinin (HA) and disease. The monoclonal antibody (mAb) against H5N1 was prepared, mAbs binding to human kidney tissue were screened, and the reactivities of mAbs with five different subtypes of influenza virus were detected. Design and synthesize the peptides according to the common amino acid sequence of these antigens, and analyze the distribution of the epitope on the crystal structure of HA. Immunological methods were used to detect whether the heterophilic epitopes could induce the production of antibodies that cross-react with kidney tissue. The results showed that H5-30 mA b binding to human kidney tissue recognized the heterophilic epitope 191-LVLWGIHHP-199 on the head of HA. The key amino acid were V192, L193, W194 and I196, which were highly conserved in human and avian influenza virus HA. The heterophilic epitope could induce mice to produce different mAbs binding to kidney tissue. Such heterophilic antibodies were also detected in the serum of the patients. It can provide materials for the mechanism of renal diseases caused by influenza virus infection.

Infection-Related Glomerulonephritis in Children and Adults

Infection-related glomerulonephritis is an immunologically mediated glomerular injury after an infection. Glomerulonephritis may occur with the infection or after a variable latent period. Poststreptococcal glomerulonephritis (PSGN) is the prototype of infection-related glomerulonephritis. The streptococcal antigens, nephritis-associated plasmin-like receptor and streptococcal exotoxin B, have emerged as major players in the pathogenesis of PSGN. Although PSGN is the most common infection-related glomerulonephritis in children, in adults, glomerulonephritis is secondary to bacteria such as staphylococci, viruses such as hepatitis C, and human immunodeficiency virus, and, rarely, parasitic infections. Supportive therapy is the mainstay of treatment in most infection-related glomerulonephritis. Treatment of the underlying infection with specific antibiotics and antiviral medications is indicated in some infections. Parasitic infections, although rare, may be associated with significant morbidity. Poststreptococcal glomerulonephritis is a self-limiting condition with a good prognosis. However, bacterial, viral, and parasitic infections may be associated with significant morbidity and long-term consequences. Epidemiologic studies are required to assess the global burden of infection-related glomerulonephritis. A better understanding of the pathogenesis of infection-related glomerulonephritis may unravel more treatment options and preventive strategies.

The pathological spectrum of pediatric kidney disease: 18-Year experience from a single tertiary care center in northern Taiwan

BACKGROUND

Glomerular disease is one of the leading causes of chronic kidney disease in children worldwide. Recent studies outlined the changing spectrum of glomerular disease in certain countries. Therefore, our study aimed to evaluate the histopathological patterns and changes in pediatric kidney disease over the past 18 years in northern Taiwan.

METHODS

This was a retrospective chart review study of pediatric patients (≤18 years of age) undergoing percutaneous renal biopsies (PRBs) of native kidneys between January 2002 and July 2020 from a Pediatric Care Center at Chang Gung Memorial Hospital, Taoyuan, Taiwan.

RESULTS

This study analyzed a total of 339 pediatric native PRBs. The mean age of the subjects was 13.7 ± 7.0 years (184 girls and 155 boys). The most common indications of PRBs included acute nephritic syndrome (55.7%), idiopathic nephrotic syndrome (22.7%), persistent asymptomatic hematuria (13.9%), and unexplained renal failure (7.7%). Our study revealed that proliferative lupus nephritis (LN), minimal change disease (MCD)-related nephrotic syndrome, and IgA nephropathy (IgAN) were the most frequent biopsy-proven pediatric glomerular diseases. In addition, we showed that severe acute post-streptococcal glomerulonephritis (APSGN) was infrequent and has not even been diagnosed since 2010.

CONCLUSION

Our result revealed that the spectrum of biopsy-proven pediatric kidney disease has not changed significantly over the past two decades. Furthermore, proliferative LN, MCD, and primary IgAN continue to be the most common histopathological diagnoses among Taiwanese children.

Using Genomics to Understand the Epidemiology of Infectious Diseases in the Northern Territory of Australia

The Northern Territory (NT) is a geographically remote region of northern and central Australia. Approximately a third of the population are First Nations Australians, many of whom live in remote regions. Due to the physical environment and climate, and scale of social inequity, the rates of many infectious diseases are the highest nationally. Molecular typing and genomic sequencing in research and public health have provided considerable new knowledge on the epidemiology of infectious diseases in the NT. We review the applications of genomic sequencing technology for molecular typing, identification of transmission clusters, phylogenomics, antimicrobial resistance prediction, and pathogen detection. We provide examples where these methodologies have been applied to infectious diseases in the NT and discuss the next steps in public health implementation of this technology.

Acute Post-Streptococcal Glomerulonephritis In Children: A Comprehensive Review

BACKGROUND

Acute post-streptococcal glomerulonephritis (APSGN) is an immune-complex (ICs) mediated glomerular disease triggered by group A β-hemolytic streptococcus (GAS) or Streptococcus pyogenes infections. APSGN represents a major cause of acquired kidney injury in children.

METHODS

This non-systematic review summarizes recent evidence on APSGN. We discuss the epidemiology, pathogenesis, clinical and laboratory findings, histopathology, treatment and prognosis of the disease.

RESULTS

The median APSGN incidence in children in developing countries is estimated at 24.3/100,000 per year, compared with 6.2/100,000 per year in developed countries. Nephritis-associated plasmin receptor, identified as glyceraldehyde-3-phosphate dehydrogenase, and the cationic cysteine proteinase streptococcal pyrogenic exotoxin B are thought to be two leading streptococcal antigens involved in the pathogenesis of APSGN, which activate the complement system, mainly via the alternative but also the lectin pathway. This process is critical for the generation of inflammation by the ICs deposited in the glomerulus. The classic phenotype is an acute diffuse proliferative glomerulonephritis leading to features of the nephritic syndrome including hematuria, oliguria, hypertension and edema. The histopathology shows that the glomeruli are diffused affected, mostly presenting enlarged glomerular tuffs due to hypercellularity. Proliferative endothelial and mesangial cells and inflammation are also observed. APSGN frequently has spontaneous recovery. There is no specific therapy, but its morbidity and mortality are drastically reduced by the prevention and/or treatment of complications.

CONCLUSION

Despite recent advances, the pathogenesis of APSGN is not fully understood. There is no specific treatment for APSGN. The prognosis is generally good. However some cases may evolve to chronic kidney disease.

Concomitant rapidly progressive glomerulonephritis and acute rheumatic fever after streptococcus infection: a case report

Acute post-streptococcal glomerulonephritis (APSGN) and acute rheumatic fever (ARF) are common immune-mediated complications after group A streptococcus (GAS) infection. The causative antigenic epitopes on GAS are different for APSGN and ARF, and their simultaneous occurrence is uncommon. A 12-year-old boy presented with fever and gross haematuria. He had subcutaneous nodules on the dorsum of both feet along with a new holosystolic murmur at the apex, and he developed hypertension and generalised oedema after admission. Investigation confirmed the diagnosis of ARF with APSGN. He received a corticosteroid to control inflammation of both the conditions. His clinical signs gradually improved but he still had rheumatic heart disease. As both diseases can occur in the same patient, treatment should be provided for both conditions.Abbreviations: APSGN: acute post-streptococcal glomerulonephritis; ARF: acute rheumatic fever; ASO: antistreptolysin O; Cr: serum creatinine; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; GAS: group A streptococcus; RBC: red blood cells; RPGN: rapidly progressive glomerulonephritis; S1: first heart sound; S2: second heart sound; TTE: transthoracic echocardiogram.

Renal autoimmunity: The role of bacterial and viral infections, an extensive review

Autoimmunity is a process by which the loss of self-tolerance results in an immune attack against the body own tissues and organs. For autoimmunity to occur, various elements serving as triggers were described by which infections are considered one of the leading factors. In turn, renal involvement in autoimmune diseases, whether by an organ-specific attack, or as part of a systemic disease process, is well known. As bacterial and viral infections are considered to be common triggers for autoimmunity in general, we aimed to study their association with renal autoimmunity in particular. We performed an extensive search of the recent and relevant medical literature regarding renal autoimmunity syndromes such as infection-associated glomerulonephritis and vasculitis, associated with bacterial and viral infections. By utilizing PubMed and Google Scholar search engines, over 200 articles and case reports were reviewed. Among other mechanisms, direct infection of the renal parenchyma, molecular mimicry, induction of B-cells or secretion of superantigens, bacterial and viral pathogens were found to correlate with the development of renal autoimmunity. Nevertheless, this was not true for all pathogens, as some mimic autoimmune diseases and others show a surprisingly protective effect. The exact immunopathogenesis is yet to be determined, however. For conclusion, bacterial and viral infections are linked to renal autoimmunity by both direct damage and as mediators of systemic diseases. Further research particularly on the immunopathogenetic mechanisms of renal autoimmunity associated with infections is required.

Sociodemographic determinants of chronic kidney disease in Indigenous children

Rates of chronic kidney disease (CKD) are disproportionately increased in Indigenous peoples. The focus has traditionally been on adults, as they experience the highest rates of kidney failure requiring kidney replacement therapy. The impacts of colonization, systemic racism, and sociodemographic marginalization however impact the health of Indigenous peoples across the lifespan. This review presents the social context within which Indigenous children develop and the impact relevant to kidney health across the developmental stages. In utero exposures impact nephron endowment which can manifest in glomerular hyperfiltration and sclerosis as well as an increased risk of congenital anomalies of the kidney and urinary tract. Young children are at increased risk of autoimmune conditions, secondary to infectious and environmental exposures, and are also exposed to the impacts of a Western lifestyle manifesting early onset overweight/obesity. Adolescents begin to manifest more severe metabolic complications such as type 2 diabetes. The impacts of early onset diabetes are associated with aggressive kidney complications and high rates of kidney failure in young adulthood. Finally, the key elements of successful prevention and treatment strategies are discussed including the importance of screening for asymptomatic, modifiable early disease, linked with clinical primary and tertiary care follow-up, and culturally relevant and safe care.

Autoimmunity in Acute Poststreptococcal GN: A Neglected Aspect of the Disease

Acute poststreptococcal GN (APSGN) is the prototype of immune complex GN and is associated with manifestations of autoimmune reactivity that have been neglected as epiphenomena. Recently, studies have demonstrated transient antifactor B autoantibodies that activate the alternative complement pathway, bringing self-immunity to a central position in the pathogenesis of APSGN. Therefore, examining other manifestations of autoimmunity that have been reported in association with poststreptococcal GN is of interest. This article reviews the renal and extrarenal manifestations of autoimmune reactivity in APSGN and considers their potential relevance in modifying the usually benign clinical course of the disease. It also discusses related aspects of the nephritogenic antigens, complement activation, and genetic elements associated with immune reactivity and their potential relevance to the familial incidence of the disease.

Concerns for efficacy of a 30-valent M-protein-based Streptococcus pyogenes vaccine in regions with high rates of rheumatic heart disease

The prevalence of rheumatic heart disease (RHD) in the Aboriginal population of the Australian Northern Territory is high, and Streptococcus pyogenes skin infections likely contribute to this. A promising candidate S. pyogenes “30mer” vaccine is composed of 30 pharyngitis associated type-specific antigens from the S. pyogenes M protein. Cross opsonisation experiments suggest that 30mer vaccine protection may extend to non-cognate emm types. A new “emm cluster” scheme for classifying M protein is based on the full-length coding sequence, and correlates with functional and immunological properties, and anatomical tropism. Twenty-seven years of research in the Northern Territory has yielded 1810 S. pyogenes isolates with clinical and emm type data. The primary aim was to analyse these data with reference to the emm cluster scheme and cross opsonisation information, to inform estimation of 30mer vaccine efficacy in the Northern Territory. The isolates encompass 101 emm types. Variants of cluster A-C were enriched in throat isolates, and variants of emm cluster D enriched in skin isolates. Throat isolates were enriched for 30mer vaccine cognate emm types in comparison with skin isolates of which only 25% were vaccine emm types. While cross opsonisation data indicates potential for enhancing 30mer vaccine coverage, more than one third of skin isolates were within 38 emm types untested for cross opsonisation. Emm cluster D variants, in particular emm cluster D4, were not only all non-cognate with the vaccine, but were abundant and diverse, and less likely to be cross-opsonisation positive than other emm clusters. Long term persistence of many emm types in the study area was revealed. It was concluded that the 30mer vaccine efficacy in the Northern Territory will likely require both cross protection, and additional measures to elicit immunity against variants of emm cluster D.

The bacterium Streptococcus pyogenes causes throat and skin infections. A danger from such infections is an immune response that attacks human heart tissue, leading to rheumatic heart disease, which is difficult to treat and potentially deadly. Disadvantaged populations such as the Indigenous people in remote tropical northern Australia have high burdens of S. pyogenes skin infection, and rheumatic heart disease. An effective vaccine would be a benefit, but none is approved for clinical use. We analysed data from 1810 S. pyogenes isolates from north Australia obtained over 28 years, to determine the potential of a previously described S. pyogenes vaccine candidate to be effective in this region. Only one quarter of the isolates from skin infections had a surface antigen corresponding to any one of the 30 antigen variants in the candidate vaccine. Previous work in animals indicates potential cross-protection from the vaccine against strains with mismatched antigens. However, even if this occurs in humans, protection against skin infection strains would likely remain compromised, unless there were additional components in the vaccine. Further studies on cross-protection are critical to defining the potential of this type of vaccine in populations burdened with S. pyogenes skin infections and rheumatic heart disease.