Antibody responses to collagen peptides and streptococcal collagen-like 1 proteins in acute rheumatic fever patients.

Acute rheumatic fever (ARF) is a serious post-infectious immune sequelae of Group A streptococcus (GAS). Pathogenesis remains poorly understood, including the events associated with collagen autoantibody generation. GAS express streptococcal collagen-like proteins (Scl) that contain a collagenous domain resembling human collagen. Here, the relationship between antibody reactivity to GAS Scl proteins and human collagen in ARF was investigated. Serum IgG specific for a representative Scl protein (Scl1.1) together with collagen-I and collagen-IV mimetic peptides were quantified in ARF patients (n = 36) and healthy matched controls (n = 36). Reactivity to Scl1.1 was significantly elevated in ARF compared to controls (P < 0.0001) and this was mapped to the collagen-like region of the protein, rather than the N-terminal non-collagenous region. Reactivity to collagen-1 and collagen-IV peptides was also significantly elevated in ARF cases (P < 0.001). However, there was no correlation between Scl1.1 and collagen peptide antibody binding, and hierarchical clustering of ARF cases by IgG reactivity showed two distinct clusters, with Scl1.1 antigens in one and collagen peptides in the other, demonstrating that collagen autoantibodies are not immunologically related to those targeting Scl1.1. Thus, anti-collagen antibodies in ARF appear to be generated as part of the autoreactivity process, independent of any mimicry with GAS collagen-like proteins.

Vaginal microbiota in pregnant women with inflammatory rheumatic and inflammatory bowel disease: A matched case-control study.

BACKGROUND: Rheumatic diseases and vaginal infections both increase the risk of preterm birth. It is unclear whether pregnant women with rheumatic disease are more likely to experience vaginal infections, which might potentially accumulate modifiable risk factors. OBJECTIVE: In this study, we sought to evaluate the vaginal microbiota of pregnant women with inflammatory rheumatic and inflammatory bowel disease. METHODS: A total of 539 asymptomatic women with singleton pregnancy were routinely screened for an abnormal vaginal microbiota between 10 + 0 and 16 + 0 gestational weeks. Vaginal smears were Gram-stained and microscopically analysed. Those with inflammatory diseases (with or without immunomodulatory therapy) were assigned to the case group and matched in a 1:3 ratio to healthy pregnant controls. RESULTS: Overall, an abnormal vaginal microbiota occurred more frequently among women of the case group, compared with those of the control group (33.8% vs 15.6%; 95% CI: 1.78-4.27, p < .001). In particular, Candida colonisation (22.3% vs 9.2%; 95% CI: 1.69-4.75, p < .001), but also bacterial vaginosis (14.9% vs 7.2%; 95% CI: 1.25-4.1, p = .006), occurred more often in the case than in the control group. No significant difference was found with regard to the occurrence of an abnormal vaginal microbiota between subgroups with and without immunomodulatory treatment (37.0% vs 27.1%; 95% CI: 0.29-1.35, p = .232). CONCLUSION: Pregnant women with inflammatory rheumatic and inflammatory bowel disease are at risk for bacterial vaginosis and Candida colonisation, which might pose a risk for preterm birth. Prospective studies are needed to further evaluate the influence of autoimmune conditions and immunosuppressive therapy on the vaginal microbiota.

PIMS-TS, the New Paediatric Systemic Inflammatory Disease Related to Previous Exposure to SARS-CoV-2 Infection-"Rheumatic Fever" of the 21st Century?

Paediatric inflammatory multisystem syndrome temporally associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (PIMS-TS) is a new systemic inflammatory disease that mainly affects children. Its course in many features resembles that of acute rheumatic fever (ARF). Therefore, it is interesting that the experiences with ARF can be used in the management of patients with PIMS-TS. The aim of the article is to analyse the current data on PIMS-TS in relation to ARF. PIMS-TS and ARF are associated with an abnormal immune response to specific pathogens (SARS-CoV-2 and group A streptococcus, respectively). The main symptoms of both diseases are fever and cardiac involvement. Current therapy for PIMS-TS is based on anti-inflammatory treatment: intravenous immunoglobulin (first-line), intravenous glucocorticoids (second-line), or biological therapy (third-line; including interleukin [IL]-1 antagonists, IL-6 receptor blockers, and anti-tumour necrosis factor agents). Vaccination might be good prophylaxis, but the efficacy and safety of the vaccines against SARS-CoV-2 have not yet been established in children. Interesting insights may be gained by considering PIMS-TS in light of what is known of ARF due to their similar courses, but there are still many unanswered questions surrounding this disease and its pathogenesis.

School-based Streptococcal A Sore-throat Treatment Programs and Acute Rheumatic Fever Amongst Indigenous Maori: A Retrospective Cohort Study.

BACKGROUND: Acute rheumatic fever (ARF) predominantly affects indigenous Maori schoolchildren in Bay of Plenty region, and more so male Maori students, especially when socioeconomically deprived. We evaluated the effectiveness of strategies for reducing ARF with group A streptococcal pharyngitis treatment in 2011-18. METHODS: We retrospectively assessed outcomes of 3 open cohorts of Maori schoolchildren receiving different interventions: Eastern Bay rural Cohort 1, mean deprivation decile 9.80, received school-based sore-throat programs with nurse and general practice (GP) support; Eastern Whakatane township/surrounds Cohort 2, mean deprivation 7.25, GP management; Western Bay Cohort 3, mean deprivation 5.98, received predominantly GP care, but 3 highest-risk schools received school-based programs. Cases were identified from ICD10 ARF-coded hospital discharges, notifications to Ministry of Health, and a secondary-prevention penicillin database. Primary outcomes were first-presentation ARF cohorts' incidence preintervention (2000-10) and postintervention (2011-18) with cases over annual school rolls' Maori students-year denominators. RESULTS: Overall, ARF in Maori schoolchildren declined in the cohorts with school-based programs. Cohort 1 saw a postintervention (2011-18) decline of 60%, 148 to 59/100,000/year, rate ratio (RR) = 0.40(CI 0.22-0.73) P = 0.002. Males' incidence declined 190 to 78 × 100,000/year RR = 0.41(CI 0.19-0.85) P = 0.013 and females too, narrowing gender disparities. Cohort 3 ARF incidence decreased 48%, 50 to 26/100,000/year RR = 0.52(CI 0.27-0.99) P = 0.044. In contrast, ARF doubled in Cohort 2 students with GP-only care without school-based programs increasing 30 to 69/100,000/year RR = 2.28(CI 0.99-5.27) P = 0.047, especially for males 39/100,000/year to 107/100,000/year RR = 2.71(CI 1.00-7.33) P = 0.0405. CONCLUSIONS: School-based programs with indigenous Maori health workers' sore-throat swabbing and GP/Nurse support reduced first-presentation ARF incidence in Maori students in highest-risk settings.

The effect of group A streptococcal carrier on the epidemic model of acute rheumatic fever.

BACKGROUND: Group A streptococcus (GAS) is the most frequent cause of bacterial pharyngitis in school-aged children. The postinfection sequel as acute rheumatic fever (ARF) and rheumatic heart disease that cause morbidity and mortality among young people is public health concerns in several developing countries. Asymptomatic carriage state of GAS is not fully understood in terms of host and bacterial factors. Although the ability of transmitting GAS of the asymptomatic carriers is relatively low, they may present the reservoir of the epidemic. A fraction of GAS carriers is difficult to estimate in practice and may greatly vary between populations. Understanding the role of carriage on the transmission dynamic of GAS is important for assessing the public health impact of the ARF. METHOD: This study investigates the effect of GAS carriers on both the transmission and dynamic of ARF cases by using a mathematical model. RESULT: We derive the sufficient conditions for which the GAS can spread or extinct from the naive population under the variation of the fraction of symptomatic cases over the incidence of GAS. The threshold is possible to occur in general, but the last condition which is rather restrictive and involves parameter uncertainty. The increasing of carriers in the endemic state leads to the reduction in magnitude of the reproduction number and the number of ARF patients. We demonstrate that the adjustment of parameters can be carried out by the use of endemic state and some specific data. CONCLUSION: We show theoretically that the presence of asymptomatic carriers may induce the epidemic threshold and reduce the virulence of GAS and the prevalence of ARF.

Molecular Mimicry, Autoimmunity, and Infection: The Cross-Reactive Antigens of Group A Streptococci and their Sequelae.

The group A streptococci are associated with a group of diseases affecting the heart, brain, and joints that are collectively referred to as acute rheumatic fever. The streptococcal immune-mediated sequelae, including acute rheumatic fever, are due to antibody and cellular immune responses that target antigens in the heart and brain as well as the group A streptococcal cross-reactive antigens as reviewed in this article. The pathogenesis of acute rheumatic fever, rheumatic heart disease, Sydenham chorea, and other autoimmune sequelae is related to autoantibodies that are characteristic of autoimmune diseases and result from the immune responses against group A streptococcal infection by the host. The sharing of host and streptococcal epitopes leads to molecular mimicry between the streptococcal and host antigens that are recognized by the autoantibodies during the host response. This article elaborates on the discoveries that led to a better understanding of the pathogenesis of disease and provides an overview of the history and the most current thought about the immune responses against the host and streptococcal cross-reactive antigens in group A streptococcal sequelae.

Report: Metformin potential in predisposing arthralgia, type II cross reactivity secondary to group A streptococcus infection & other comorbidities in treating PCOS.

One of the most common endocrinological disorder affecting women in adolescence is Polycystic Ovarian Syndrome (PCOS). Women suffering from PCOS diagnosed with follicles in ovaries show enlarged reproductive organs with small filled follicles. Unusual bleeding, prolonged menstruation, unwanted hair growth, accumulation of fat and acne are the most common problems experienced by adolescents with PCOS. Nowadays, PCOS is treated successfully with the oral antidiabetic drug, metformin and hormone replacement therapy. Its off-label use is still controversial with unknown mechanisms due to patient risk versus benefit hypothesis by practitioners as they successfully treat PCOS in adolescents with metformin. But in few reported cases metformin has potential to induce back pain and swollen joints less frequently with rare cases of behavior alteration. Penicillin belongs to the beta-lactam antibiotics and is most commonly used to treat rheumatic fever although it has potential to cause allergic reactions affecting 10% of patients who exhibit IgE-mediated immunological reactions. Here, we present a case of a female diagnosed with PCOS who after treatment with metformin for more than two years, reported with hyperuricemia, migraine, neurological pain, severe joint and knee pains on shoulders and legs, and rheumatic fever. After treatment with benzathine benzyl penicillin for rheumatic fever, the patient also exhibited Type IV delayed hypersensitivity reaction.

Understanding group A streptococcal pharyngitis and skin infections as causes of rheumatic fever: protocol for a prospective disease incidence study.

BACKGROUND: Group A Streptococcal (GAS) infections cause the autoimmune disease acute rheumatic fever (ARF), which can progress to chronic rheumatic heart disease (RHD). Treating pharyngitis caused by GAS with antibiotics is important in preventing ARF. However, it is difficult to distinguish these infections from GAS carriers. There is growing evidence for GAS skin infections as a cause of ARF. This study will identify the incidence of true GAS pharyngitis and serological responses to GAS skin infections. The effectiveness of antibiotics for these conditions will be explored, and modifiable risk factors. Serum antibody titres indicating the upper limits of normal (ULN for ASO/ADB antibodies) will be established alongside carriage rates in asymptomatic children. METHODS: This is a prospective disease incidence study, with an associated case-control study. The study population includes 1000 children (5-14 years) from Auckland, New Zealand, 800 of whom have visited their healthcare professional, resulting in a throat or skin swab for GAS, and 200 who are asymptomatic. The conditions of interest are GAS throat swab positive pharyngitis (n = 200); GAS carriage (n = 200); GAS negative throat swab (n = 200); GAS skin infections (n = 200); and asymptomatic controls (n = 200). All participants, except asymptomatic controls, will have acute and convalescent serological testing for ASO/ADB titres (collected < 9 days, and 2-4 weeks following symptom onset, respectively), alongside viral PCR from throat swabs. Asymptomatic controls will have ASO/ADB titres measured in one blood specimen and a throat swab for microbial culture. Caregivers of children will be interviewed using a questionnaire and any GAS isolates identified will be emm typed. The persistence of GAS antibodies will also be investigated. DISCUSSION: Findings from this study will fill critical gaps in scientific knowledge to better understand the pathophysiology of ARF, improve clinical management of GAS infections, and design more effective ARF prevention programmes. In particular it will measure the incidence of true, serologically confirmed GAS pharyngitis; assess the immune response to GAS skin infections and its role as a cause of ARF; examine the effectiveness of oral antibiotics for treating GAS pharyngitis and carriage; and identify whether risk factors for GAS infections might provide intervention points for reducing ARF.

Utility of Detecting sof Gene as Evidence of Streptococcus pyogenes Infection in Acute Rheumatic Fever.

OBJECTIVE: To determine the diagnostic accuracy of polymerase chain reaction-based detection of sof gene compared to throat swab culture for S. pyogenes infection in patients with acute rheumatic fever and those with recurrence of rheumatic activity. METHODS: 40 patients between 3 to 18 years of age, with clinical diagnosis of acute rheumatic fever or new activity in established rheumatic heart disease were included. The amplicon of 228bp of sof gene was detected using a polymerase chain reaction-based technique and the results were compared with throat swab culture for Streptococcus pyogenes. RESULTS: 10 patients had a positive throat swab culture and 11 had sof gene detected. The sensitivity and specificity of the test was 100% and 96.7%, respectively compared to throat swab culture (P=0.001). The positive predictive value and the negative predictive value was 90.9% and 100% respectively. CONCLUSION: Polymerase chain reaction-based detection of sof gene provides an alternative to throat swab culture in diagnosing activity in Acute Rheumatic Fever or established Rheumatic heart disease.

Four-Weekly Benzathine Penicillin G Provides Inadequate Protection against Acute Rheumatic Fever in Some Children.

This study aimed to identify recurrent acute rheumatic fever (ARF) episodes which occurred despite adherence to prophylactic benzathine penicillin G (BPG). Data from Australia's Northern Territory were analyzed; ARF recurrences between 2012 and 2017 diagnosed while the person was prescribed BPG were identified. Days at risk (DAR)-median and interquartile range-preceding ARF onset were calculated. The timing of BPG doses was examined for individuals with no DAR. One hundred sixty-nine ARF recurrences were analyzed; median DAR in the previous 8 weeks before ARF onset was 29. Most recurrences occurred following > 7 DAR (87%). Eight recurrences (5%) occurred despite no DAR; all were aged less than 16 years at the time of their recurrence/s. Recurrent ARF most commonly occurs after delayed BPG doses, but in some cases, receiving every prescribed BPG dose on time did not prevent recurrent ARF. A method to identify high-risk individuals before recurrent ARF is needed.

Streptococcal Serology in Acute Rheumatic Fever Patients: Findings From 2 High-income, High-burden Settings.

BACKGROUND: Globally, there is wide variation in streptococcal titer upper limits of normal (ULN) for antistreptolysin O (ASO) and anti-deoxyribonuclease B (ADB) used as an evidence of recent group A streptococcal infection to diagnose acute rheumatic fever (ARF). METHODS: We audited ASO and ADB titers among individuals with ARF in New Zealand (NZ) and in Australia's Northern Territory. We summarized streptococcal titers by different ARF clinical manifestations, assessed application of locally recommended serology guidelines where NZ uses high ULN cut-offs and calculated the proportion of cases fulfilling alternative serologic diagnostic criteria. RESULTS: From January 2013 to December 2015, group A streptococcal serology results were available for 350 patients diagnosed with ARF in NZ and 182 patients in Northern Territory. Median peak streptococcal titers were similar in both settings. Among NZ cases, 267/350 (76.3%) met NZ serologic diagnostic criteria, whereas 329/350 (94.0%) met Australian criteria. By applying Australian ULN titer cut-off criteria to NZ cases, excluding chorea, ARF definite cases would increase by 17.6% representing 47 cases. CONCLUSIONS: ASO and ADB values were similar in these settings. Use of high ULN cut-offs potentially undercounts definite and probable ARF diagnoses. We recommend NZ and other high-burden settings to use globally accepted, age-specific, lower serologic cut-offs to avoid misclassification of ARF.

How Many Doses Make a Difference? An Analysis of Secondary Prevention of Rheumatic Fever and Rheumatic Heart Disease.

Background Acute rheumatic fever ( ARF ) and rheumatic heart disease cause substantial burdens worldwide. Long-term antibiotic secondary prophylaxis is used to prevent disease progression, but evidence for benefits of different adherence levels is limited. Using data from northern Australia, we identified factors associated with adherence, and the association between adherence and ARF recurrence, progression to rheumatic heart disease, worsening or improvement of rheumatic heart disease, and mortality. Methods and Results Factors associated with adherence (percent of doses administered) were analyzed using logistic regression. Nested case-control and case-crossover designs were used to investigate associations with clinical outcomes; conditional logistic regression was used to estimate odds ratios ( OR ) with 95% CIs Adherence estimates (7728) were analyzed. Being female, younger, having more-severe disease, and living remotely were associated with higher adherence. Alcohol misuse was associated with lower adherence. The risk of ARF recurrence did not decrease until ≈40% of doses had been administered. Receiving <80% was associated with a 4-fold increase in the odds of ARF recurrence (case-control OR : 4.00 [95% CI : 1.7-9.29], case-crossover OR : 3.31 [95% CI : 1.09-10.07]) and appeared to be associated with increased all-cause mortality (case-control OR : 1.90 [95% CI : 0.89-4.06]; case-crossover OR 1.91 [95% CI : 0.51-7.12]). Conclusions We show for the first time that increased adherence to penicillin prophylaxis is associated with reduced ARF recurrence, and a likely reduction in mortality, in our setting. These findings can motivate patients to receive doses since even relatively low adherence can be beneficial, and additional doses further reduce adverse clinical outcomes.

Poststreptococcal reactive arthritis in Japan.

Reactive arthritis after Group A streptococcal infection (poststreptococcal reactive arthritis: PSRA) that does not meet the Jones criteria for acute rheumatic fever (ARF) has been reported as a new entity for over a decade. In Japan there are few reports of PSRA. We encountered four children with arthritis accompanied with Group A streptococcal infection in our department. We investigated our cases and the recent Japanese literature. Japanese cases of PSRA are frequently accompanied with uveitis and erythema nodosum, and tonsillectomy resolved their symptoms in some cases. There were overlap cases between ARF, juvenile idiopathic arthritis, and PSRA.

Streptococcal pharyngitis and rheumatic heart disease: the superantigen hypothesis revisited.

Streptococcus pyogenes is a human-specific and globally prominent bacterial pathogen that despite causing numerous human infections, this bacterium is normally found in an asymptomatic carrier state. This review provides an overview of both bacterial and human factors that likely play an important role in nasopharyngeal colonization and pharyngitis, as well as the development of acute rheumatic fever and rheumatic heart disease. Here we highlight a recently described role for bacterial superantigens in promoting acute nasopharyngeal infection, and discuss how these immune system activating toxins could be crucial to initiate the autoimmune process in rheumatic heart disease.

The novel Group A Streptococcus antigen SpnA combined with bead-based immunoassay technology improves streptococcal serology for the diagnosis of acute rheumatic fever.

OBJECTIVES: Streptococcal serology provides evidence of prior Group A Streptococcus (GAS) exposure, crucial to the diagnosis of acute rheumatic fever (ARF) and post-streptococcal glomerulonephritis. However, current tests, which measure anti-streptolysin-O and anti-DNaseB antibodies, are limited by false positives in GAS endemic settings, and incompatible methodology requiring the two tests to be run in parallel. The objective was to improve streptococcal serology by combining the novel GAS antigen, SpnA, with streptolysin-O and DNaseB in a contemporary, bead-based immunoassay. METHODS: Recombinant streptolysin-O, DNAseB and SpnA were conjugated to polystyrene beads with unique fluorescence positions so antibody binding to all three antigens could be detected simultaneously by cytometric bead array. Multiplex assays were run on sera collected in three groups: ARF; ethnically matched healthy children; and healthy adults. RESULTS: The ability of the antigens to detect a previous GAS exposure in ARF was assessed using the 80th centile of the healthy children group as cut-off (upper limit of normal). SpnA had the highest sensitivity at 88%, compared with 75% for streptolysin-O and 56% for DNaseB. CONCLUSIONS: SpnA has favorable immunokinetics for streptococcal serology, and can be combined with anti-streptolysin-O and anti-DNaseB in a multiplex format to improve efficiency and accuracy.

Association of rheumatic fever & rheumatic heart disease with plausible early & late-stage disease markers.

BACKGROUND & OBJECTIVES: Rheumatic fever (RF) and rheumatic heart disease (RHD) are the autoimmune sequelae caused by Group A Streptococcus. RHD still remains a major concern in the developing countries due to its poor diagnosis, lack of vaccines and social awareness among population. This study was aimed to identify the plausible early- and late-stage disease markers associated with RF/RHD. METHODS: A total of 84 patients with confirmed pharyngitis (n=18), RF (n=23) and RHD (n=43) were included in the comparative analysis of different factors involved in host-pathogen interaction during RF/RHD pathogenesis. RESULTS: This study revealed high titre of serum antistreptolysin O (ASO) antibody in pharyngitis compared to RF and RHD patients, whereas procollagen type 1 C-peptide (PICP) level was elevated in RHD which showed an inverse correlation with serum ASO titre. The significant elevation of serum anti-peptide associated with RF (PARF) antibody in RF patients was correlated as a probable stage-specific determinant. In addition, pro-inflammatory cytokine profile revealed high levels of interleukin-12 (IL-12)/IL-23p40, IL-17A in RF, whereas IL-6 concentration was higher in RHD compared to healthy controls. INTERPRETATION & CONCLUSIONS: The overall assessment of the factors/ disease markers involved in host-pathogen interaction in RF/RHD may be suggestive of plausible disease marker in different groups of patients. Further studies with larger sample need to be done to better understand RF/RHD pathogenesis.

Emm type distribution of group A streptococcus isolates from the throat swabs of children living in areas with a high (Northland and Gisborne) or low (Palmerston North) incidence of acute rheumatic fever.

AIM: To assess the circulating emm types of pharyngeal isolates of group A streptococcus (GAS) among school children living in Northland, the Gisborne region and Palmerston North, New Zealand. METHODS: GAS were isolated from throat swabs sent to laboratories in Northland (197 in 2013) and Gisborne (115 in 2014-15) and from children enrolled in the Palmerston North Solar Ventilation Project (70 in 2013-14). The incidences of acute rheumatic fever (ARF) cases in the three regions in 2014 were 9, 19.1 and 0 cases per 100,000 for Northland, the Gisborne region and Palmerston North respectively. DNA sequencing of the N-terminal portion of the emm gene was performed at the Institute of Environmental Science and Research Limited (ESR) laboratory (Porirua, New Zealand). RESULTS: A total of 36 emm types were found among pharyngeal GAS isolates from Northland children with emm1 predominating (24%), 28 emm types from the Gisborne region with emm12 predominating (25%) and 20 emm types from Palmerston North, again with emm12 predominating (36%). Of these GAS isolates, 38% were emm pattern A-C, usually associated with throat infections, 23% were pattern D, usually associated with skin infections, and 39% pattern E or generalists. The most common of the 13 emm clusters detected were A-C4 (emm12; 18% isolates), A-C3 (emm1, emm227, emm238; 17% isolates), D4 (9 emm types; 16% isolates), E4 and E3 (8 emm types each; 15% and 10% isolates respectively). A total of 301 of the 376 (80%) isolates were serotypes previously associated with ARF in New Zealand. CONCLUSION: The only significant differences in distribution between the regions with high (Northland and Gisborne area) and low (Palmerston North) incidences of ARF were the presence of emm3 and absence of emm41 among GAS isolates from Palmerston North school children.