Evaluation of cytokines produced by β-hemolytic streptococcus in acute pharyngotonsillitis / Avaliação das citosinas produzidas por estreptococos β-hemolíticos em faringotonsilites agudas

INTRODUCTION: The most common pathogen in bacterial pharyngotonsillitis is group A β-hemolytic streptococcus, although groups B, C, F,and G have also been associated with pharyngotonsillitis.OBJECTIVE: To assess the levels of the cytokines TNF-α, IL-6,IL-4, and IL-10 in bacterial pharyngotonsillitis caused by group A and non-A (groups B, C, F and G) β-hemolytic streptococcus.METHODS: The study was conducted at a pediatric emergency care unit. The sample comprised children (5-9 years old) with acute bacterial pharyngotonsillitis diagnosed between December of 2011 and May of 2012. The research involved collection of blood samples from the patients, enzyme-linked immunosorbent assay detection of TNF-α, IL-6,IL-4, and IL-10, and collection of two oropharyngeal swabs for bacterial isolation. Additionally, the medical history of the study participants was also collected.RESULTS: In the studied group (mean age: 5.93 years), higher pharyngotonsillitis incidence was observed in the female gender (64.76%). Higher incidence of tonsillar exudates was observed with groups A and C. No statistically significant differences in cytokine levels were observed among groups. However, the group A and the control group showed a difference in the IL-6 level (p = 0.0016).CONCLUSIONS: The Groups A and C showed higher cytokine levels than the Groups B and control, suggesting similar immunological patterns.

INTRODUÇÃO: O patógeno mais comumente associado à faringotonsilite bacteriana é o estreptococo β-hemolítico do grupo A, a despeito dos grupos B, C, F e G terem também sido associados com a faringotonsilite.OBJETIVO: Determinar os níveis das citosinas TNF-α, IL-6, IL-4, e IL-10 na faringotonsilite bacteriana causada pelos estreptococos β-hemolíticos do grupo A e não-A (grupos B, C, F e G).MÉTODO: O estudo foi conduzido em uma emergência pediátrica. A amostra estudada compreendeu crianças (entre 5 e 9 anos) com faringotonsilite aguda bacteriana diagnosticada entre dezembro de 2011 e maio de 2012. A pesquisa envolveu a coleta de amostras sanguíneas dos pacientes, a detecção, através do ELISA, de TNF-α, IL-6, IL-4, and IL-10, além da coleta de dois swabs orofaríngeos para isolamento bacteriano. Adicionalmente foi coletada a história médica dos participantes do estudo.RESULTADOS: No grupo estudado (idade média: 5,93 anos), a maior incidência de faringotonsilite foi observada no gênero feminino (64,76%). Foram detectadas maiores incidências de exsudatos tonsilares nos grupos A e C. Não foram observadas diferenças estatisticamente significantes dos níveis de citosinas entre os grupos. Porém os grupos A e o controle mostraram diferença nos níveis de IL-6 (p = 0.0016).CONCLUSÕES: Os grupos A e C mostraram maiores níveis de citosinas que os grupos B e o controle, sugerindo mecanismos imunológicos similares.

Impacto do uso da prova rápida para estreptococo beta-hemolítico do grupo A no diagnóstico e tratamento da faringotonsilite aguda em pronto-socorro de Pediatria / Impact of the rapid antigen detection test in diagnosis and treatment of acute pharyngotonsillitis in a Pediatric emergency room / Impacto del uso de la prueba rápida para estreptococos beta-hemolíticos del grupo A en el diagnóstico y tratamiento de la faringotonsilitis en emergencia de Pediatría

OBJETIVO: Avaliar o impacto da realização rotineira da prova rápida para pesquisa de estreptococo do grupo A no diagnóstico e tratamento da faringotonsilite aguda em crianças. MÉTODOS: Estudo prospectivo e observacional que contou com a utilização de protocolo de pesquisa estabelecido na Unidade de Emergência do Hospital Universitário da Universidade de São Paulo para o atendimento de crianças e adolescentes com faringotonsilite aguda. RESULTADOS: Com base na avaliação clínica, dos 650 pacientes estudados, antimicrobianos seriam prescritos para 389 indivíduos (59,8%) e, com o uso da pesquisa de estreptococo do grupo A, foram prescritos em 286 pacientes (44,0%). Das 261 crianças que não receberiam antibiótico pelo quadro clínico, 111 (42,5%) tiveram pesquisa de estreptococo do grupo A positiva. O diagnóstico baseado no quadro clínico apresentou sensibilidade de 61,1%, especificidade de 47,7%, valor preditivo positivo de 44,9% e valor preditivo negativo de 57,5%. CONCLUSÕES: O diagnóstico clínico da faringotonsilite estreptocócica mostrou baixa sensibilidade e especificidade. O uso rotineiro da prova rápida para pesquisa de estreptococo permitiu a redução do uso de antibióticos e a identificação de um grupo de risco para as complicações da infecção estreptocócica, pois 42,5% dos pacientes com prova rápida positiva não receberiam antibióticos, se levado em consideração apenas o diagnóstico clínico.

OBJECTIVE: To evaluate the impact of the routine use of rapid antigen detection test in the diagnosis and treatment of acute pharyngotonsillitis in children. METHODS: This is a prospective and observational study, with a protocol compliance design established at the Emergency Unit of the University Hospital of Universidade de São Paulo for the care of children and adolescents diagnosed with acute pharyngitis. RESULTS: 650 children and adolescents were enrolled. Based on clinical findings, antibiotics would be prescribed for 389 patients (59.8%); using the rapid antigen detection test, they were prescribed for 286 patients (44.0%). Among the 261 children who would not have received antibiotics based on the clinical evaluation, 111 (42.5%) had positive rapid antigen detection test. The diagnosis based only on clinical evaluation showed 61.1% sensitivity, 47.7% specificity, 44.9% positive predictive value, and 57.5% negative predictive value. CONCLUSIONS: The clinical diagnosis of streptococcal pharyngotonsillitis had low sensitivity and specificity. The routine use of rapid antigen detection test led to the reduction of antibiotic use and the identification of a risk group for complications of streptococcal infection, since 42.5% positive rapid antigen detection test patients would not have received antibiotics based only on clinical diagnosis.

OBJETIVO: Evaluar el impacto de la realización de rutina de la prueba rápida para investigación de estreptococos del grupo A en el diagnóstico y tratamiento de la faringotonsilitis aguda en niños. MÉTODOS: Estudio prospectivo y observacional que contó con el uso de protocolo de investigación establecido en la Unidad de Emergencia del Hospital Universitario de la USP para la atención a niños y adolescentes con faringotonsilitis aguda. RESULTADOS: Con base en la evaluación crítica, de los 650 pacientes estudiados, antimicrobianos serían prescritos a 389 individuos (59,8%) y, con el uso de la investigación de estreptococos del grupo A se los prescribieron a 286 pacientes (44,0%). De los 261 niños que no recibirían antibióticos por el cuadro clínico, 111 (42,5%) tuvieron investigación de estreptococos del grupo A positiva. El diagnóstico basado en el cuadro clínico presentó sensibilidad del 61,1%, especificidad del 47,7%, valor predictivo positivo del 44,9% y valor predictivo negativo del 57,5%, CONCLUSIONES: En este estudio, el diagnóstico clínico de la faringotonsilitis estreptocócica mostró baja sensibilidad y especificidad. El uso de rutina de la prueba rápida para investigación de estreptococos permitió la reducción del uso de antibióticos y la identificación de un grupo de riesgo para las complicaciones de la infección estreptocócica, pues el 42,5% de los pacientes con prueba rápida positiva no recibirían antibióticos si se llevara en consideración solamente el diagnóstico clínico.

[Streptococcus super antigen in polyp tissue of patients with nasal polyposis and chronic rhinosinusitis in comparison to normal population]

Nasal polyp [NP] is a benign mucosal mass located in both sinuses and nares which is mostly seen in association with cystic fibrosis, asthma or oversensitivity to aspirin. The prominent histological feature of NP is inflammatory cell infiltration with eosinophil predominance. Superantigens role in causing NP complications is already proven. Superantigens, which are mostly originated from Streptococci and Staphylococci, activate T cells strongly and increase the process of production and release of cytokines, and secretion of IgE from B cells, which in turn directly affects proinflammatory cells such as eosinophils, both in their tissues infiltration and functions. The samples are collected from patients referring to ENT clinic in Rasoul Akram training Hospital in Tehran after thorough clinical and paraclinical examinations. For control group the samples collected from patients undergoing rhinoplasty. All the samples kept frozen and sent to immunology lab. The DNA of the excised tissues extracted and amplified by using the superantigens specific primers and PCR product detected by gel electrophoresis. The date analyzed by using mean and SD and CHI[2] analytical tools. Fifteen healthy individuals, 25 patients with rhinosinusitis and 24 with polyposis entered this trial. Group A Streptococcus toxin detection was significantly more frequent in those with nasal polyp and rhinosinusitis compared to healthy individuals [P=0.001 and 0.005, respectively], but the results were almost the same for those with nasal polyp and rhinosinusitis [P=0.4]. Streptococci may play an important role in induction or clinical exacerbation of polyposis and group A Streptococcus pyogenes exotoxin [SPEs] with superantigenic effects may have a crucial role in etiology and pathogenesis of polyps with or without rhinosinusitis. It is postulated that, T cells polyclonal activation by SPEs may cause recruitment of inflammatory cells in nasal mucosa. These inflammatory cells include IgE producing B cells leading to allergic and inflammatory reactions in NP.

Immunoasssay chromatographic antigen test for rapid diagnosis of Group A beta hemolytic Streptococcus pharyngitis in children: a cross/ sectional study

Group A beta-hemolytic streptococcus [GABHS] is an important pharyngotonsillitis etiologic agent in children. The objective of this study was diagnosis of streptococcal pharyngitis based on rapid antigen detection test and conventional pharyngeal culture. The rapid GABHS antigen detection test was compared to culture on blood agar, the gold standard for the diagnosis of this etiologic agent. Streptococcal antigen was detected in pharyngeal specimens of 34.5% of cases by rapid strip test. We detected group A Streptococcus in 17.2% of pharyngeal culture. There was no agreement between two methods [PV < 0.1]. The negative pharyngeal culture results are probably due to antibiotic usage in 43.2% of patients. Positive rapid test results in pharyngeal swab was age dependent [P < 0.05]. There was good correlation between observing the [petechia in pharynx of patients] and positive rapid test in pharyngeal swab [P < 0.004]. Throat culture results were relatated to previous antibiotic usage [P < 0.03]. The rapid test in pharyngeal swab is helpful for rapid diagnosis and treatment of GABHS pharyngitis. Diagnosis of GABHS pharyngitis based on soley clinical findings is misleading in the majority of cases. Petechia observed in pharynx of the cases was highly predictive of streptococcal pharyngitis

Pathology and pathogenesis of rheumatic heart disease.

Cardiovascular disease is on the rise. In India and other developing countries, rheumatic heart disease (RHD) continues to be a major public health problem and contributes to significant cardiac morbidity and mortality. RHD in the juvenile age group namely juvenile mitral stenosis is a variant which is unique to the Indian subcontinent. Severe valve deformities lead to high morbidity and mortality. Despite various measures no appreciable decline in prevalence of RHD has been documented. At autopsy, mitral valve was most commonly affected either alone or in combination with aortic and tricuspid valves. Both functional and organic involvement of tricuspid valve was documented. It has been convincingly demonstrated that molecular mimicry between Streptococcus pyogenes antigen and human proteins lead to autoimmune reactions both humoral and cell mediated causing RF/RHD. Heart tissues namely the valves, left atrial appendage (LAA) and myocardium reveal variable amounts of infiltration by lymphocytes. Significant endocarditis and valvulitis is observed in these cases. CD4+ T cells are most likely the ultimate effectors of chronic valve lesions in RHD. They can recognize Streptococcal M5 protein peptides and produce various inflammatory cytokines such as TNF-alpha, IFN-gamma, IL-10, IL-4 which could be responsible for progressive fibrotic valvular lesions. Cardiac myosin has been defined as a putative autoantigen recognized by autoantibodies of RF patients. Cross reactivity between cardiac myosin and group A beta hemolytic Streptococcal M protein has been adequately demonstrated. Cardiac myosin has been shown to produce myocarditis in rats and mice. Valvulitis/ endocarditis has been observed in excised LAA, cardiac valves and in hearts at autopsy from cases of RHD. The disease predominantly affects the valvular endocardium culminating in crippling valve deformities. Endocardial infiltrate and their migration into the valve substance has been elegantly demonstrated in rats and mice. Immune responses against cardiac myosin lead to valvular heart disease and infiltration of the heart by Streptococcal M protein reactive T lymphocytes. Mitral valves showed various degrees of calcification. An interesting observation is the nature of calcification in diseased/distorted valves in RHD. Recent studies indicate that calcification is not merely an inactive, "dystrophic" process but involves a regulated inflammatory process associated with expression of osteoblast markers and neoangiogenesis. Increased plasma osteopontin levels correlated with severity of mitral valve calcification. Further evidence of inflammation is supported by high levels of advanced oxidation protein products and high sensitive C-reactive protein in plasma detected in patients with RHD. Presence of inflammatory cells and increased expression of several cytokines in cases of "end stage" RHD reflects a possible subclinical, ongoing insult/injury to some unrecognized antigenic stimulus by beta hemolytic Streptococcal antigens that have sensitized/primed the various target tissues and which further culminate in permanent valve deformities.

Papel do teste de detecção rápida do antígeno do estreptococcus beta-hemolítico do grupo a em pacientes com faringoamigdalites / Role of rapid antigen detection test for the diagnosis of group-A beta-hemolytic streptococcus in patients with pharyngotonsillitis

O Streptococcus beta-hemolítico do grupo A (SGA) é o agente etiológico mais comum das faringoamigdalites (FA). O diagnóstico etiológico correto e tratamento adequado evitam complicações supurativas e não-supurativas da faringoamigdalite estreptocócica, entretanto, métodos clínicos de diagnóstico não são confiáveis. Os métodos rápidos de detecção do antígeno do SGA podem ser utilizados no diagnóstico deste agente e evitar uso indevido de antibióticos. OBJETIVOS: Os autores objetivaram avaliar a sensibilidade e especificidade dos testes rápidos para detecção do antígeno do SGA em nosso meio. FORMA DE ESTUDO: Clínico prospectivo. METODOLOGIA: Oitenta e um pacientes com faringoamigdalite aguda, atendidos no PS-ORL do Hospital das Clínicas da FMUSP, no período de maio de 2001 a abril de 2002, foram submetidos a duas coletas simultâneas de material de orofaringe com swabs. O teste rápido de detecção do SGA foi confrontado com a cultura em placa agar-sangue ("gold standard" para o diagnóstico etiológico). RESULTADOS: De 81 pacientes, 56 por cento tiveram teste rápido positivo e 44 por cento negativo; 40.7 por cento apresentaram crescimento de SGA na cultura; a sensibilidade e especificidade do teste rápido foram, respectivamente, 93,9 por cento e 68,7 por cento. O valor preditivo negativo e positivo foram, respectivamente, 94,2 por cento e 67,4 por cento. CONCLUSÕES: A alta sensibilidade do exame permite utilizá-lo com intuito de identificar pacientes com SGA. Os testes de detecção rápida do antígeno estreptocócico se mostraram uma importante arma coadjuvante no diagnóstico etiológico das faringoamigdalites.

Group A beta-hemolytic streptococcus (GAS) is an important pharyngotonsillitis etiologic agent. Correct etiologic diagnosis and early treatment prevent suppurative and non-suppurative complications of streptococcal pharyngotonsillitis, however, clinical diagnostic methods are not reliable. Within this context, rapid detection methods of GAS antigen are useful to diagnose this agent. AIM: The objective of the present study was to determine the sensitivity and specificity of rapid GAS antigen detection tests used in Brazil. STUDY DESIGN: Clinical prospective. METHODS: Eighty-one patients with clinical diagnosis of acute pharyngotonsillitis seen at the otorhinolaryngology emergency department of University Hospital, FMUSP, between May 2001 and April 2002, were submitted to two simultaneous collections of oropharyngeal material using swabs. Rapid GAS antigen detection test was compared to culture on blood agar, the gold standard for the diagnosis of this etiologic agent. RESULTS: Among the 81 studied patients, the rapid test was positive in 56 percent and negative in 44 percent. GAS growth in culture was observed for 40.7 percent of the patients. The sensitivity and specificity of the rapid test were, respectively, 93.9 percent and 68.7 percent, and the negative and positive predictive values were 94.2 and 67.4 percent, respectively. CONCLUSIONS: We concluded that the high sensitivity of the test permits its use for the identification of patients with GAS. Rapid streptococcal antigen detection tests have been shown to be an important supporting tool in the etiologic diagnosis of pharyngotonsillitis.

Papel do teste de deteccão rápida do antígeno do estreptococcus pyogenes do grupo a em pacientes com faringoamigdalites / Role of rapid antigen detection test for the diagnosis of group A beta-hemolytic streptococcus in patients with pharyngotonsillitis

O Streptococcus pyogenes do grupo A (SGA) é o agente etiológico mais comum das faringoamigdalites (FA). O diagnóstico etiológico correto e tratamento adequado evitam complicacões supurativas e não-supurativas da faringoamigdalite estreptocócica, entretanto, métodos clínicos de diagnóstico não são confiáveis. Os métodos rápidos de deteccão do antígeno do SGA podem ser utilizados no diagnóstico deste agente e evitar uso indevido de antibióticos. OBJETIVOS: Os autores objetivaram avaliar a sensibilidade e especificidade dos testes rápidos para deteccão do antígeno do SGA em nosso meio. FORMA DE ESTUDO: Clínico prospectivo. CASUíSTICA E MÉTODO: Oitenta e um pacientes com faringoamigdalite aguda, atendidos no PS-ORL do Hospital das Clínicas da FMUSP, no período de maio de 2001 a abril de 2002, foram submetidos a duas coletas simultâneas de material de orofaringe com swabs. O teste rápido de deteccão do SGA foi confrontado com a cultura em placa agar-sangue ("gold standard" para o diagnóstico etiológico). RESULTADOS: De 81 pacientes, 56 por cento tiveram teste rápido positivo e 44 por cento negativo; 40.7 por cento apresentaram crescimento de SGA na cultura; a sensibilidade e especificidade do teste rápido foram, respectivamente, 93,9 por cento e 68,7 por cento. O valor preditivo negativo e positivo foram, respectivamente, 94,2 por cento e 67,4 por cento. COMENTARIOS FINAIS: A alta sensibilidade do exame permite utilizá-lo com intuito de identificar pacientes com SGA. Os testes de deteccão rápida do antígeno estreptocócico se mostraram uma importante arma coadjuvante no diagnóstico etiológico das faringoamigdalites.

Determinação de anti-estreptolisina "O" e proteína C reativa entre escolares do município de Laranjal, PR / Determination of antistreptolysin \"O\" and C-reactive protein among school children of Laranjal, PR

Para a determinação de anti-estreptolisina "O" e proteína C reativa, no município de Laranjal-PR, foram analisados soros de 411 escolares, entre 5 a 16 anos. Para anti-estreptolisina "O", 13,6 por cento tiveram títulos elevados e 5,1 por cento foram reativos para proteína C reativa. Não foram observadas diferenças em relação ao sexo e faixa etária.

Immune responses of a liposome/ISCOM vaccine adjuvant against streptococcal fibronectin binding protein 1 (Sfb1) in mice.

BACKGROUND & OBJECTIVES: The fibronectin binding protein Sfb1 of Streptococcus pyogenes is a well characterised antigen which induces protection against lethal challenge with group A streptococcus (GAS) when adjuvanted with cholera toxin B-subunit (CTB). As an alternative to CTB adjuvanted intranasal immunisations we investigated the immune responses generated in mice using Sfb1 incorporated in to the skin and mucosal adjuvant SAMA4. METHODS: Mice (BALB/c) were vaccinated intradermally with 100 microl of either SAMA4 (adjuvant only group) or SAMA4/Sfb1 and were boosted 7 days later. Mice vaccinated with CTB based vaccines were immunised by intranasal inoculation with a mixture containing 30 microg Sfb1 and 10 microg CTB on days 1, 3, 5 and 15. At 14 days after the last booster immunisation the immune response was characterised and mice were challenged with 10(8) CFU of S. pyogenes. RESULTS: Mice vaccinated with SAMA4/Sfb1 elicited a Sfb1-specific IgG response in the sera that was significantly higher than that seen in control mice and mice immunised with the adjuvant only (P<0.05). No significant differences were seen for specific IgA antibodies in the sera in all groups examined. Compared with non-immunised and adjuvant only immunised controls, mice immunised with the Sfb1/SAMA4 vaccine exhibited a significant increase (P<0.05) in the number of Sfb1 reactive spleen cells in lymphoproliferation assays which were three fold higher than those seen for mice vaccinated with the Sfb1/CTB vaccine. Mice vaccinated with CTB/Sfb1 had the highest level of protection (80%) as where mice vaccinated with SAMA4 and SAMA4/Sfb1 displayed no protection (20% and 40%). INTERPRETATION & CONCLUSION: These data suggest that the SAMA4 adjuvant used in this study fails to elicit protective immunity in BALB/c mice when used to adjuvant the known protective antigen Sfb1.

Prospecting for new group A streptococcal vaccine candidates.

BACKGROUND & OBJECTIVES: Most group A streptococcal (GAS) vaccine strategies focused on the surface M protein of the GAS. However, vaccine based on M protein have some drawbacks. In the present study, we used two approaches to identify new proteins and peptides that may have utility as vaccine candidates. METHODS: A whole gel elution procedure was used to separate GAS surface antigens into 9 size fractionated pools. Mice were vaccinated with each pool and antibody titre, opsonic ability and protective capacity measured. In an alternative approach BioInformatics was used to identify putative GAS surface proteins. Peptides from within these proteins were then selected on the basis of predicted antigenicity or location. These peptides were conjugated to keyhole lymphocyanin (KLH) and immunogenicity measured in a mouse model. RESULTS: One pool of GAS surface proteins (approximately 29kDa) induced antibodies that were both opsonic and potentially protective. Immunoflourescent microscopy demonstrated that these antibodies bound to the surface of M1 GAS. Amino acid sequencing subsequently identified superoxide dismutase as the major antigen in this pool. A BioInformatic search of the M1 GAS genome and subsequent analysis identified several peptides that fulfilled criteria as potential vaccine candidates. Each peptide when conjugated to KLH was able to induce a strong antibody response. INTERPRETATION & CONCLUSION: Several new antigens were identified that may have potential as vaccine targets. A future GAS vaccine may have multiple peptide epitopes, providing protection against multiple GAS strains.

Anti-streptolysin O titers in normal healthy children of 5-15 years.

Antistreptolysin O (ASO) levels vary with age group of the study population and geographical locations. The present study was undertaken to determine the upper limit of normal of ASO in 200 normal children of 5-15 years of age with no history of recent sore throat infection. The standard tube dilution method (WHO) was used for estimating ASO titers. It was found that 239 IU was the upper limit of normal in the study population, which can be considered as the baseline ASO titer. This can provide useful guidelines for physicians in the interpretation of elevated ASO titers in cases of suspected acute rheumatic fever.

Streptococcal antibodies among rural school children in Bangladesh.

The upper limit of normal values of group A streptococcal antibodies should be known for a population concerned because it is influenced by many local conditions. As yet the reference value of the these antibodies has not been determined by using a quantitative method among Bangladeshi children. We determined the reference value of anti-streptolysin O and anti-deoxyribonuclease B among 361 apparently healthy rural Bangladeshi primary school children (aged 5 to 14 years, mean 9.2 years). Anti-streptolysin O was measured by an auto-analyzer and antideoxyribonuclease B was measured by microtitre method. The geometric mean titres for the entire group was 241 IU/ml and 222 IU/ml for anti-streptolysin O and anti-deoxyribonuclease B respectively. The upper limit of normal values (80th percentile) was 390 and 340 for anti-streptolysin O and anti-deoxyribonuclease B, respectively. These limits should be of value to physicians, epidemiologists and clinical laboratory personnel as well.

Humoral immune response in a sample of Bangladeshi children with rheumatic fever.

Several researchers have investigated cellular response, and antibody response to different antigens of group A beta-haemolytic streptococci, cardiac tissues and B cell alloantigen in rheumatic fever (RF). However, immunoglobulins (Ig) which may indicate general immune status did not receive attention. This study was done in the outpatient clinic of the National Center for Control of Rheumatic Fever and Heart Diseases, Dhaka, to compare Ig levels in subjects with and without RF who have had recent group A beta-haemolytic streptococcal infections. We have recruited 44 RF cases aged 5 to 20 years, and 44 subjects without RF were randomly matched for age and sex as controls. Convalescent blood samples were used to measure antistreptolysin O and IgG, IgM, and IgA levels. The cases, as compared with the controls, had significantly higher levels of antistreptolysin O (mean 399 versus 321 IU/ml), IgG (mean 2386 versus 1885 mg/dl), IgM (mean 286 versus 222 mg/dl) and IgA (mean 258 versus 184 mg/dl). It is not clearly known why the immune response is higher in the RF cases. We have to elucidate factors responsible for higher immune response in children with RF.

Improvement of the indirect hemagglutination test for the detection of antibodies to Streptococcus pyogenes

An indirect hemagglutination test for a seroepidemiological survery of Streptococcus pyogenes infection was standardized. This is an improved modification of the indirect hemagglutination test which utilizes an unstable reagent prepared with fresh blood cells. Two types of bacterial antigens represented by extracellular products and purified streptolysin O were assayed but only the former antigen gave good results. Pretreatment of the bacterial antigen with 0.15 M NaOH and neutralization to pH 5.5, as well as postfixation of sensitized red cells with 0.1 per cent glutaraldehyde at 56 degrees Celsius for 30 min were found to be essential to give long stability to the reagent in liquid suspension, at least 9 months at 4 degrees Celsius. A total of 564 serum samples with high, moderate and low anti-streptolysin 0 antibodies as determined by the neutralization assay were studied by the indirect hemagglutination test using the new reagent. The sensitivity, specificity, efficiency, positive predictive value and negative predictive value of the test in relation to the neutralization assay were 0.950, 0.975, 0.963, 0.973, and 0.955, respectively. The kappa agreement index between the two techniques was high (0.926) and ranked as "almost perfect". Antibody levels detected by both techniques also presented a high positive correlation (r(s)=0.726). Five reagent batches sucessively produced proved to be reproducible. Thus, the improved indirect hemagglutination test seems to be useful for public health laboratories.

Pharyngeal colonisation, ADNB response and development of cardiac lesions in mice following intranasal inoculation with group A beta haemolytic streptococcus M type 18.

Swiss albino mice from a randomly bred colony were inoculated intranasally with 1.6, 2 or 2.4 x 10(7) colony forming units of a mid-logarithmic phase culture of group A beta haemolytic streptococcus M type 18 for 3 days, 6 days or once a week respectively for three weeks. Pharyngeal colonisation could be observed in 67 (59.8%) of 112 mice on 4th day after inoculation and 14 (38%) of the 37 mice on 21st day. Out of 27 mice tested for determination of antibodies to deoxyribonuclease B at regular intervals for 98 days, 15 (55.5%) showed responses, with maximum titers varying from 50 units to 4800 units in individual mice. Histopathological evidence for cardiac lesions were seen in five (3.03%) of the 165 animals studied. These included one case of severe endocarditis, two cases of endocarditis with valvular lesions and one case with non-specific lymphocyte infiltration in the heart. One other animal showed subendocardial oval nodular aggregates. Although the cellular nature of these lesions were not determined, this study shows that Swiss albino mice can serve as suitable animal models to study experimental streptococcal infections. However these are preliminary observations and are to be confirmed and revalidated by further controlled experiments.

Febre reumática: perfis imunoquímicos desenvolvidos por antígenos celulares e extracelulares do Streptococcus pyogenes e isotipos de anticorpos de pacientes com a doença / Rheumatic fever: immunochemical profiles developed by cellular and extracellular antigens of Streptococcus pyogenes and antibody isotypes from patients with the disease

Como sequela da faringite aguda causada por S. pyogenes, cerca de 3 por cento dos indivídios acometidos desenvolvem febre reumática (FR), uma doença grave, de difícil diagnóstico, näo existindo uma prova laboratorial segura para a mesma. Neste trabalho foram analisados, pela técnica de "western-blot", os antígenos (Ag) celulares e extracelulares de s. pyogenes frente a 188 soros dos quais, 56 de pacientes com FR aguda, 91 com suspeita de infecçäo estreptocócica e 41 controles sadios, visando identificar as bandas antigênicas reativas com os diferentes isotipos de anticorpos (Ac). Os Ac IgG identificaram, no ag celular, bandas maiores que 100 kDa, que reagiram exclusivamente com os soros de pacientes com FR, as quais nos deram uma sensibilidade de 96 por cento e especificidade de 100 por cento no diagnóstico da doença. Os perfis imunoquímicos desenvolvidos principalmente por Ag celular e Ac IgG, em conjunto com a presença de ac IgA, constituem marcadores precoces da patogênese da febre reumática. Os dados mostraram ainda capacidade potencial da técnica para discriminar pacientes reumáticos de indivíduos sadios

Faringitis en niños de 3 a 14 años: evaluación de un método de diagnóstico / Pharyngitis in children aged 3 to 14 years: evaluation of a diagnosis method

Con el objetivo de determinar la utilidad de un método de diagnóstico etiológico rápido en las faringitis se estudiaron 98 niños que consultaron en el Servicio de Urgencia Pediátrica del CASMU. A todos se le realizaron dos exudados faríngeos: uno para cultivo convencional y otro se utilizó para detectar la presencia de antígenos de estreptococo beta hemolítico del grupo A por método inmunoenzimático (Test Pack Abbott). La sensibilidad y especificidad de este último método con respecto al cultivo fue de 91 y 94,5 por ciento. No se encontraron diferencias significativas en los signos y síntomas entre los niños con faringitis estreptocócica y no estreptocócica. La utilización de este método permite un tratamiento más racional pero su sensibilidad no es lo suficientemente elevada para resolver definitivamente el dilema del manejo de esta frecuente afección pediátrica

Anticuerpos contra productos extracelulares del estreptococo grupo A: importancia diagnóstica en la fibre reumática aguda / Antibodies against extracellular products of group a streptococcus. its diagnostic value in acute rheumatic fever

La infección estreptocóccica de la faringe es condición sine qua non el desarrollo de la fiebre reumática (FR), La demostración de esa infección suele requerir métodos inmunoserológicos que detectan anticuerpos contra productos extracelulares del estreptococo (PEE). Se evaluó la respuesta inmune humoral contra PEE en niños y adultos con y sin diagnóstico de FR. Se estableció que la distribución de valores para anti-estreptolisina O (AEL-O) no es gaussiana y que el valor de referencia debe manejarse como percentila. En adultos la percentila 97 es 227, en niños la percentila 90 es 451. En caso de FR, todos los enfermos excepto uno tuvo valores superiores. Una prueba de aglutinación que reconoce otros anticuerpos a PEE (Estreptozima mr), mostró en menores de 15 años que 15/28 los tenían a título bajo, en cambio en el grupo con FR sólo 1 mostró ausencia de esos anticuerpos. A mayor título de AEL-O mayor título en Estreptozima. Los métodos probados son eficientes para reconocer la respuesta inmune humoral contra PEE