Niveles de protección contra Haemophilus influenzae tipo b en niños, adolescentes y adultos cubanos / Levels of protection against Haemophilus influenzae type b in Cuban children, adolescents and adults

La concentración de los anticuerpos contra el polisacárido capsular polirribosilribitol fosfato del Haemophilus influenzae tipo b se considera un buen indicador serológico para evaluar protección contra la enfermedad invasiva. Existen pocos reportes que estudien la inmunidad serológica en Cuba. El objetivo general de este estudio fue determinar los niveles de protección séricos contra Haemophilus influenzae tipo b en niños, adolescentes y adultos cubanos, en una muestra de 575 individuos. Se cuantificó la concentración de IgG anti-polirribosilribitol fosfato de Haemophilus influenzae tipo b mediante un inmunoensayo enzimático estandarizado y validado en el laboratorio de inmunología del Centro Nacional de Genética Médica, La Habana, Cuba. Se determinaron las concentraciones medias geométricas de anticuerpos y los niveles de protección frente a la enfermedad invasiva por Haemophilus influenzae tipo b. La concentración media geométrica de IgG anti-polirribosilribitol fosfato fue de 1,94 μg/mL (IC95 por ciento 1,80; 2,08) y fue mayor en el grupo de 16 a 22 años. El porcentaje con protección de larga duración fue mayor para el sexo femenino que para el masculino (82,2 por ciento vs 71,4 por ciento; p=0,0339) entre los que poseían inmunidad natural. El grupo de sujetos nacidos en el periodo en que se vacunó con la vacuna conjugada cubana QUIMI-HIB® presentó concentraciones medias geométricas superiores (2,75 μg/mL, IC95 por ciento 2,00; 3,79). El 99,1 por ciento de los participantes presentó protección frente a la enfermedad invasiva por Haemophilus influenzae tipo b, el 19,8 por ciento a corto plazo y el 79,3 por ciento protección de larga duración. El inmunoensayo validado para la cuantificación de IgG anti-polirribosilribitol fosfato podría emplearse en estudios de seroprevalencia. En los sujetos estudiados, se encontró un predominio de elevadas concentraciones de IgG anti- polirribosilribitol fosfato del Haemophilus influenzae tipo b que confieren protección de larga duración(AU)

The levels of antibodies directed against the capsular polysaccharide polyribosylribitol phosphate of Haemophilus influenzae type b are considered a good serological indicator to assess the immunity against invasive disease. In Cuba, there are few reports that study serological immunity. The general objective was to determine serum protection levels against Haemophilus influenzae type b in Cuban children, adolescents and adults, in a sample of 575 Cuban individuals. The concentration of IgG against Haemophilus influenzae type b was quantified by means of an indirect ELISA standardized and validated in the immunology laboratory of the National Center of Medical Genetics, Havana, Cuba. The geometric mean concentration of IgG anti- polyribosylribitol phosphate and the levels of protection against invasive Haemophilus influenzae type b disease were determined. The geometric mean concentration of IgG anti- polyribosylribitol phosphate was 1.94 μg/mL (95percentCI 1.80;2.08) and the group from 16 to 22 years old presented the highest. Among those with natural immunity, the percentage with long-term protection was higher for females vs. males (82.2percent vs. 71.4percent; p=0.0339). The group of subjects born in the period in which they were vaccinated with the Cuban conjugate vaccine QUIMI-HIB® presented higher geometric mean concentration (2.75 μg/mL, CI95percent 2.00; 3.79). The 99.1percent of the participants had protection against invasive Haemophilus influenzae type b disease, 19.8percent short-term and 79.3percent long-term protection. The ELISA for the quantification of anti- Haemophilus influenzae type b IgG antibodies, developed and validated, could be used in seroprevalence studies. In the subjects studied, there was a predominance of high IgG anti- Haemophilus influenzae type b polyribosylribitol phosphate concentration values that confer long-term protection(AU)

Prevalencia de anticuerpos de tipo IgG e IgM contra COVID-19 en personal municipal esencial en Ushuaia, Tierra del Fuego, Argentina / Prevalence of IgG e IgM antibodies against COVID-19 in essential municipal personnel. Ushuaia, T. del Fuego, Argentina

Con el propósito de ampliar el conocimiento epidemiológico sobre la circulación del SARS-CoV-2 en la ciudad de Ushuaia durante el brote ocurrido de marzo a mayo de 2020, nos planteamos realizar un estudio observacional, de corte transversal, de mayo a julio, buscando la respuesta serológica al contacto con el virus en trabajadores esenciales municipales. N=1305. Los datos fueron ingresados a una plataforma con ingreso restringido, para luego cruzar las variables obtenidas en formato Excel. La mayoría de las personas estudiadas fueron de género masculino, con una media de edad de 38,5 años. El 20% de las personas con IgG+ tuvieron nexo epidemiológico. La prevalencia fue del 2,75%. Quienes presentaron IgM+ fueron descartados por otro método, considerándose falsos positivos. La idea y realización en forma precoz del estudio fue útil para evaluar la diseminación viral asintomática en el personal municipal afectado a tareas esenciales y tomar decisiones en las primeras etapas de la pandemia. No se encontraron diferencias significativas en los grupos más expuestos. Se observaron casos de transmisión asintomática intrafamiliar. Estas pruebas serológicas no tienen fines diagnósticos ni confieren un pasaporte inmunitario. Pudimos establecer la confiabilidad de la técnica utilizada, fundamentalmente en relación a la IgG. El método se optimizó. Consideramos que las políticas públicas basadas en evidencias científicas permiten tomar mejores decisiones en beneficio de la comunidad. Creemos que el presente estudio aporta al estado de comprensión en la materia. Cada reporte puede ser de utilidad para el conocimiento de la diseminación viral

With the purpose of expanding epidemiological knowledge about the circulation of SARS-CoV-2 in the city of Ushuaia during the outbreak that occurred from March to May of this current, we plan to carry out an observational, cross-sectional study from May to July, seeking the serological response to contact with the virus in essential municipal workers. N = 1316. The data were entered into a platform with restricted entry, to later cross the variables obtained in Excel format. Most of the people studied were male, with a mean age of 38 years. 20% of the people with IgG + had an epidemiological link. The prevalence was 2.88%. Those who presented IgM+ were discarded by another method, being considered false positives. The early idea and implementation of the study was useful to evaluate asymptomatic viral shedding in municipal personnel affected by essential tasks and to make decisions in the early stages of the pandemic. No significant differences were found in the most exposed groups. Cases of asymptomatic interfamily transmission were observed. These serological tests do not have diagnostic purposes nor do they confer an immune passport. We were able to establish the reliability of the technique used, mainly in relation to IgG. The method was optimized. We believe that public policies based on scientific evidence allow us to make better decisions for the benefit of the community. We believe that the present study contributes to the state of understanding in the matter. Each report can be useful for understanding viral shedding.

Avaliação do kit Filaria Deteção; IgG4 produzido com o antígeno recombinante Wb123 para diagnóstico da filariose linfática no Brasil / Evaluation of the Filaria Detection; IgG4 kit employing recombinant Wb123 antigen for diagnosis of lymphatic filariasis in Brazil / Evaluación de pruebas de anticuerpos antifiláricos IgG4, fabricado con el antígeno recombinante Wb123, para el diagnóstico de la filariasis linfática en Brasil

RESUMO O Plano Global de Eliminação da Filariose Linfática, lançado pela Organização Mundial da Saúde em 2000, propõe o uso de testes de detecção de antígeno circulante filarial como ferramenta diagnóstica para avaliação e monitoramento das ações de controle da parasitose. Entretanto, esses testes, apesar de apresentarem alta sensibilidade, não conseguem detectar com eficiência a infecção em seu estágio inicial, quando ainda não existe a presença de helmintos adultos. Considerando essa limitação, a pesquisa de anticorpos antifilariais tem sido apontada como uma alternativa, uma vez que os anticorpos produzidos contra as larvas infectantes do parasito são detectados antes da presença de antígeno circulante filarial. O objetivo deste estudo foi definir o ponto de corte e avaliar a acurácia do kit Filaria Detect™ IgG4 produzido com o antígeno recombinante Wb123 para diagnóstico da filariose linfática no Brasil. Para isso, foi realizado um estudo de avaliação de teste diagnóstico, no qual foram utilizadas 256 amostras de soro: 79 (30,9%) obtidas de indivíduos microfilarêmicos e 177 (60,1%), de indivíduos amicrofilarêmicos e que testaram negativo para os testes imunológicos Bm14 CELISA e Og4C3 ELISA. A definição do ponto de corte ideal, bem como da acurácia do kit Filaria Detect™ IgG4, foi obtida através da construção de curvas ROC, sendo a densidade óptica de 0,239 aquela na qual o teste obteve melhor desempenho, com sensibilidade de 81,0% e especificidade de 96,6%. Os resultados obtidos demonstraram que o kit Filaria Detect™ IgG4 é uma ferramenta promissora para investigação e monitoramento de áreas submetidas ao tratamento em massa para filariose linfática.

ABSTRACT The Global Programme to Eliminate Lymphatic Filariasis, launched by the World Health Organization in the year 2000, proposes the use of circulating filarial antigen tests as a diagnostic tool to assess and monitor initiatives to control filarial infection. However, despite a high sensitivity, these tests are not efficient to detect infection at early stages, before worms have reached the adult stage. Considering this limitation, anti-filarial antibody testing has been suggested as an alternative, given that the antibodies produced against the larvae are detectable before the presence of circulating filarial antigen. The objective of the present study was to determine the diagnostic cut-off and the accuracy of the Filaria Detect™ IgG4 kit employing recombinant Wb123 antigen for diagnosis of lymphatic filariasis in Brazil. For that, we performed a diagnostic evaluation study in which 256 serum samples were analyzed: 79 (30.9%) obtained from microfilaremic individuals and 177 (60.1%) from amicrofilaremic individuals who tested negative with the Bm14 CELISA and Og4C3 ELISA immunologic tests. The ideal cutoff as well as the Filaria Detect™ IgG4 kit accuracy were determined based on ROC curve analyses, with an optical density of 0.239 identified as the cutoff with the best performance, with 81.0% sensitivity and 96.6% specificity. The results show that the Filaria Detect™ IgG4 kit is a promising tool for investigation and monitoring of areas undergoing mass drug administration for lymphatic filariasis.

RESUMEN En el programa mundial de eliminación de la filariasis linfática, puesto en marcha por la Organización Mundial de la Salud en el año 2000, se propone el uso de pruebas de detección del antígeno filárico circulante como instrumento de diagnóstico para la evaluación y el seguimiento de las medidas de control de la parasitosis. Sin embargo, esas pruebas, a pesar de tener un alto grado de sensibilidad, no permiten detectar con eficiencia la infección en su fase inicial, cuando todavía no existen helmintos adultos. En vista de esa limitación, se ha señalado como una opción el estudio de anticuerpos antifiláricos, puesto que los anticuerpos producidos contra las larvas infectantes del parásito se detectan antes de la existencia de antígeno filárico circulante. El objetivo de este estudio fue definir el punto de corte y evaluar la exactitud del estuche Detect™ para pruebas de anticuerpos antifiláricos IgG4, fabricado con el antígeno recombinante Wb123, para el diagnóstico de la filariasis linfática en Brasil. Para ello, se realizó un estudio de evaluación de la prueba diagnóstica, en el cual se utilizaron 256 muestras de suero, a saber, 79 (30,9%) obtenidas de personas microfilarémicas y 177 (60,1%) de personas amicrofilarémicas, que arrojaron resultados seronegativos en las pruebas inmunológicas CELISA Bm14 y ELISA Og4C3. La definición del punto de corte ideal y de la exactitud del estuche Detect™ se obtuvo con la construcción de curvas de la característica operativa del receptor (ROC); una densidad óptica de 0,239 marcó el mejor nivel de desempeño de la prueba, con una sensibilidad de 81,0% y una especificidad de 96,6%. Los resultados obtenidos demostraron que el estuche Detect™ es un instrumento prometedor para la investigación y el seguimiento de las regiones donde se realiza un tratamiento masivo de la filariasis linfática.

Respuesta inmunológica a varias proteínas del H. pylori en pacientes guatemaltecos / Inmune response to various H. pylori proteins in Guatemalan patients

Se determinó la respuesta inmunológica a proteínas recombinantes de Helicobacter pylori en pacientes dis-pépticos (adultos y niños), pacientes con cáncer gástrico y sus familiares asintomáticos adultos viviendo con ellos. Se utilizó la prueba recomLine® Helicobacter IgG e IgA, y con base en el reconocimiento de los factores de virulencia VacA y CagA se determinó si la cepa de H. pylori era de tipo I o II. El análisis de los datos fue descriptivo y analítico y se estimaron los intervalos de confianza de 95%, con un nivel de error de 0.05 y Odds ratio. El 58.7% (121/206) de los pacientes presentó la bacteria en tinción histológica de biopsia, positividad que disminuyó con la edad y daño histológico. La frecuencia de la respuesta a los anticuerpos IgG fue mayor que IgA, en ambos casos ésta fue menor en los niños. Las proteínas del H. pylori más reconocidas tanto por IgA como IgG fueron VacA y CagA, y la respuesta a las otras proteínas investigadas fue mayor al aumentar el daño histológi-co. La cepa tipo I fue la que predominó en la población en estudio con 66% (136/206). Se deben continuar con los estudios de prevalencia de la cepa tipo I del H. pylori y del reconocimiento de sus antígenos en la población guatemalteca a fin de determinar su utilidad en el diagnóstico y pronóstico de la infección.

The immune response to recombinant Helicobacter pylori proteins was determined in dyspeptic patients (adults and children), patients with gastric cancer and their asymptomatic adults' relatives living with them. The recomLine® Helicobacter IgG and IgA test was used and based on the recognition of the virulence factors VacA and CagA, it was determined whether the H. pylori strain was type I or II. The data analysis was descriptive and analytic, and 95% confidence intervals were estimated, with an error level of 0.05, and Odds ratio. The patients that presented the bacterium in histological biopsy were 58.7% (121/206), positivity that decreased with age and histological damage. The frecuency of response to IgG antibodies was higher than IgA, in both cases it was lower in children. VacA and CagA were the H. pylori proteins most recognized by both IgA and IgG and it was observed that the number of recognized proteins was greater with increasing histological damage. The type I strain was the one that predominated in the study population 66% (136/206). Prevalence studies of the type I strain of H. pylori ant the recognition of its antigens in the Guatemalan population should continue in order to determine its usefulness in the diagnosis and prognosis of infection.

Immunogenicity of Whole / 生物医学与环境科学（英文）

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Measles, rubella, mumps and Toxoplasma gondii antibodies in saliva of vaccinated students of schools and universities in São Paulo City, Brazil

ABSTRACT Introduction: Vaccines are well-established public health interventions with major impacton the prevalence of infectious diseases, but outbreaks are occurring frequently due to pri-mary and secondary failures, despite high coverage. Surveillance of efficacy and duration ofinduced immunity is a difficult task as it requires invasive blood sampling in children andteenagers. Saliva can be an acceptable alternative source of IgG to assess vaccine efficacyand toxoplasmosis incidence. We investigated IgG response for measles, mumps, rubella,and T. gondii in saliva samples of vaccinated young people. Methods: Saliva was collected from 249 public schools students from São Paulo, Brazil, aged7 to 13 years old, during an interactive exhibition on hygiene. We used S. aureus proteinA solid phase capture assay for IgG reactive to biotinylated purified proteins. Paired salivaand serum (47) were tested from young adults with serum evidence of T. gondii infectionand from negative children less than 12 month old for standardization. Reproducibility wasgreater than 98% and sensitivity and specificity of the saliva assays were greater than 95%,as well as the concordance of paired saliva and serum samples. Results: Saliva from high school students showed a prevalence of 8.5% (95% CI: 5.0-11.9%)for anti T. gondii IgG; 96.8% (94.6-99%) of anti-measles IgG; 59.1% (53-65%) of anti-rubella IgG,and 57.5% (51.3-63.6%) of anti-mumps IgG. Discussion: The prevalence of antibodies against mumps and rubella after 6-8 years of vaccination was lower than against measles among students. The findings of this study demonstrate the feasibility of saliva sampling for follow-up of vaccine immune status in teenagers. This useful approach allows for IgG detection for vaccine control or epidemio- logical studies.

Seroprevalence of chikungunya virus infection in five hospitals within Anyigba, Kogi State of Nigeria

ABSTRACT Febrile illnesses in developing countries are often misdiagnosed as malaria or typhoid fever. Although arboviral infections have similar clinical symptoms, they are usually not screened because of limited resources and the fact that there are several viruses in this group. Chikungunya virus (CHIKV) has been isolated in parts of Nigeria, but there is no documented evidence of the infection in Kogi State. This study determined seroprevalence of active and past CHIKV infection among febrile patients who tested negative for malaria and typhoid fever. Sera from 243 febrile patients were screened for CHIKV IgG and IgM using an immunochromatographic test kit. Clinical and socio-demographic variables were collected using a structured questionnaire. Recent CHIKV infection was observed in 5.8% of the study participants while 25.1% had IgG antibodies demonstrating previous infection. Significant associations were observed between seropositivity and age of participants (p < 0.001), sex (p = 0.044), marital status (p = 0.002), and occupation (p < 0.001). Clinical symptoms such as fever, joint pain, and headache were significantly associated with seropositivity. This study identified recent CHIKV infection in Anyigba. Therefore, there is need for routine screening of febrile patients and molecular characterization to determine the nature of circulating strains.

Epitope of dengue virus E protein detect human antibodies associated with mild disease: a potential peptide for vaccine development

ABSTRACT The antigenic potential of seven immunogenic peptides of the dengue virus was evaluated in the sera of patients with dengue confirmed by IgM/IgG serology. Antibodies IgM and IgG against dengue virus peptides were analyzed by ELISA in 31 dengue sero-positive and 20 sero-negative patients. The P5 peptide showed significant IgG immunoreactivity mostly in the sera of patients with dengue without warning signs in comparison with patients with dengue with warning signs, correlating with mild disease. This finding suggests that the low antibody response against P5 epitope could be a risk factor for higher susceptibility to dengue virus infection with warning signs, and that P5 could be a potential antigen for vaccine development.

Low risk of serological cross-reactivity between dengue and COVID-19

In the near future, the overlap of Coronavirus disease 2019 (COVID-19) and dengue epidemics is a concrete threat in tropical regions. Co-epidemics of COVID-19 and dengue could be an overwhelming challenge for health systems in low- and middle-income countries. In this work, we investigated potential serological cross-reactions between COVID-19 and dengue patients. Among 32 COVID-19 positive sera, no positive Dengue virus (DENV) IgG/IgM results were observed. On the other hand, one false-positive result was observed among 44 DENV-positive sera tested for COVID-19 antibodies with each of the two rapid tests used. Further data on accuracy of COVID-19 diagnostic test are urgently warranted.

The direct and indirect effects of the pneumococcal conjugated vaccine on carriage rates in children aged younger than 5 years in Latin America and the Caribbean: a systematic review / Efeitos diretos e indiretos da vacina pneumocócica conjugada no estado de portador em crianças menores de 5 anos, na América Latina e no Caribe: uma revisão sistemática

ABSTRACT Objective To demonstrate the impact of pneumococcal conjugate vaccine in Streptococcus pneumoniae carriage status in children younger than 5 years in Latin America and the Caribbean. Methods A systematic literature review was carried out on the direct and indirect effects of pneumococcal vaccine in the carriage status, after implementation in childhood immunization programs. Studies carried out in children younger than 5 years were selected from the PubMed® and Virtual Health Library databases, and data collected after implementation of pneumococcal vaccine in Latin America and the Caribbean, between 2008 and 2018. Results From 1,396 articles identified, 738 were selected based on titles and abstracts. After duplicate removal, 31 studies were eligible for full-text reading, resulting in 6 publications for analysis. All selected publications were observational studies and indicated a decrease in the carriage and vaccine types, and an increase in the circulation of non-vaccine serotypes, such as 6A, 19A, 35B, 21 and 38. We did not identify changes in the antimicrobial resistance after vaccine implementation. Conclusion A decrease in the carriage status of vaccine types and non-vaccine types was detected. The continuous monitoring of pneumococcal vaccine effect is fundamental to demonstrate the impact of the carriage status and, consequently, of invasive pneumococcal disease, allowing better targeting approaches in countries that included pneumococcal vaccine in their immunization programs. Our study protocol was registered in PROSPERO (www.crd.york.ac.uk/prospero) under number CRD42018096719.

RESUMO Objetivo Demonstrar o impacto das vacinas pneumocócicas conjugadas no estado de portador de Streptococcus pneumoniae em crianças menores de 5 anos na América Latina e no Caribe. Métodos Foi realizada revisão sistemática da literatura sobre os efeitos diretos e indiretos da vacina pneumocócica no estado de portador em crianças menores de 5 anos, após a implantação da vacina nos calendários de imunização infantil. A partir de dados da PubMed®e da Biblioteca Virtual da Saúde, foram selecionados estudos de portador em crianças menores de 5 anos, com dados coletados após implementação da vacina de 2008 a 2018, na América Latina e no Caribe. Resultados Dos 1.396 artigos identificados, 738 foram selecionados mediante leitura de títulos e resumos. Após a extração dos duplicados, 31 foram elegíveis para leitura do texto completo, restando 6 artigos para análise. Todos os estudos selecionados eram observacionais e indicavam diminuição do portador e tipos vacinais, e aumento da circulação de sorotipos não vacinais, como 6A, 19A, 35B, 21 e 38. Não foi observada alteração na resistência antimicrobiana após a introdução da vacina. Conclusão Detectou-se redução no estado de portador, dos tipos vacinais e não vacinais. O monitoramento contínuo do efeito das vacinas pneumocócicas é fundamental, para demonstrar o impacto do estado de portador e, consequentemente, da doença pneumocócica invasiva, permitindo o melhor direcionamento nas ações em saúde para os países que incluíram a vacina no calendário de imunização. Nosso protocolo de estudo foi registrado no PROSPERO (www.crd.york.ac.uk/prospero) sob o número CRD42018096719.

Performance evaluation of an indirect immunofluorescence kit for the serological diagnosis of dengue / Avaliação do desempenho de kit de imunofluorescência indireta para o diagnóstico sorológico de dengue

ABSTRACT Objective: To evaluate the performance of indirect immunofluorescence for serological diagnosis of dengue virus in a population with high prevalence of arboviruses. Methods: Two-hundred serum samples from patients with clinical suspicion of dengue fever were tested by immunoenzymatic and indirect immunofluorescence assay BIOCHIP® mosaic. Specificity, sensitivity and Kappa coefficient were calculated. Discordant samples were tested by polymerase chain reaction for confirmation. Results: Of the 200 samples, 20% were positive and 80% negative for anti-dengue virus IgM antibodies in the immunoenzymatic test. Of the 40 positives, 25% were negative in indirect immunofluorescence. Of these ten discordant results, only 20% were also negative in the polymerase chain reaction (PCR). Of the 160 negatives in the immunoenzymatic test, 5% were positive in indirect immunofluorescence. Of these nine discordant results, 33% were positive in the PCR. The Kappa coefficient was 0.7 (0.572-0.829). Sensitivity and specificity of indirect immunofluorescence were respectively 75% and 94%. For anti-dengue virus IgG antibodies, of the 200 samples, 15.5% were positive and 84.5% were negative in the immunoenzymatic test. Of the 31 positives, 12.9% were negative in indirect immunofluorescence. Of these four discordant results, 25% were negative in the PCR. Of the 169 negatives, 8% were positive in indirect immunofluorescence. Of these 14 discordant results, 64% were also positive in the PCR. The Kappa coefficient was 0.695 (0.563-0.83). Sensitivity and specificity of indirect immunofluorescence were 87.1% and 91.7%, respectively. Conclusion: For diagnosis of acute infection, the immunoenzymatic test is enough, and the use of additional methods is not warranted. Replacing the immunoenzymatic test by indirect immunofluorescence would compromise the sensitivity for IgM. However, indirect immunofluorescence can distinguish three arboviruses simultaneously, an advantage during concomitant epidemics.

RESUMO Objetivo: Avaliar o desempenho da imunofluorescência indireta no diagnóstico sorológico de dengue em uma população com alta prevalência de arboviroses. Métodos: Duzentas amostras de soro de pacientes com suspeita clínica de dengue foram testadas por ensaio imunoenzimático e imunofluorescência indireta mosaico BIOCHIP®. Foram calculados especificidade, sensibilidade e coeficiente Kappa. Nas amostras discordantes, realizou-se reação em cadeia da polimerase como método confirmatório. Resultados: Das 200 amostras, 20% foram positivas e 80% negativas para IgM antivírus da dengue no ensaio imunoenzimático. Das 40 positivas, 25% foram negativas na imunofluorescência indireta. Destas dez negativas, apenas 20% eram também negativas na reação em cadeia da polimerase. Das 160 negativas no ensaio imunoenzimático, 5% foram positivas na imunofluorescência indireta. Por fim, dentre as nove discordantes, 33% tiveram vírus da dengue detectado na reação em cadeia da polimerase. O coeficiente Kappa foi 0,70 (0,57-0,82). Sensibilidade e especificidade por imunofluorescência indireta foram, respectivamente, 75% e 94%. Para IgG antivírus da dengue, de 200 amostras, 15,5% foram positivas e 84,5% negativas no ensaio imunoenzimático. Das 31 positivas, 12,9% foram negativas na imunofluorescência indireta. Destas quatro discordantes, 25% apresentaram vírus da dengue não detectado na reação em cadeia da polimerase. Das 169 negativas, 8% foram positivas na imunofluorescência indireta. Destas, 64% foram positivas também na reação em cadeia da polimerase. O coeficiente Kappa foi 0,695 (0,56-0,83). Sensibilidade e a especificidade por imunofluorescência indireta foram, respectivamente, 87,1% e 91,7%. Conclusão: Ensaio imunoenzimático seria suficiente para diagnóstico sorológico de infecção aguda, não justificando a incorporação da imunofluorescência indireta. Substituir ensaio imunoenzimático pela imunofluorescência indireta poderia comprometer a sensibilidade para IgM. Contudo, a imunofluorescência indireta auxilia diferenciar três arboviroses simultaneamente, sendo vantajoso em epidemias concomitantes.

Frecuencia de anticuerpos IgG a seis agentes infecciosos en los estudiantes de la carrera de Química Biológica / Frequency of IgG antibodies to six infectious agents in students of the Biological Chemistry degree

Se determinó la frecuencia de anticuerpos IgG para Toxoplasma gondii y los virus de paperas, sarampión, rubéola, varicela y hepatitis B en 90 estudiantes de la carrera de Química Biológica de la Facultad de CCQQ y Farmacia. La mayor frecuencia se encontró para rubéola y sarampión, 98.9% para cada prueba y la menor frecuencia fue para T. gondii con 23.3%. No se encontró asociación significativa entre la positividad y el género, entre la positividad a paperas, sarampión, varicela y el haber sufrido la infección o haber estado en contacto con personas infectadas y entre la positividad a T. gondii y el consumir carne roja y/o comida callejera (p > .05). Únicamente en el caso de la hepatitis B se encontró una asociación significativa entre la positividad y la edad (p = < .001), el hecho de estar vacunado (p < .001) y el ser sexualmente activo (p = .004). Los porcentajes de vacunación en la población en estudio fue alta únicamente para hepatitis B (80%), mientras que para las otras infecciones fue 35.6% para rubéola y sarampión, 22.2% para varicela y 10% para paperas. Más de 82% de los estudiantes presentaron protección a los seis agentes estudiados y se recomienda realizar encuestas sero-epidemiológicas constantes, evaluar los programas de inmunización, identificar los grupos a riesgo y que las personas que no presenten anticuerpos se vacunen.

The frequency of IgG antibodies for Toxoplasma gondii and the mumps, measles, rubella, varicella and hepa-titis B viruses was determined in 90 students of the Biological Chemistry career of the Faculty of CCQQ and Pharmacy. The highest frequency was found for Rubella and Measles, 98.9% each, and the lowest frequency was for T. gondii with 23.3%. No significant difference was found between positivity and gender, between positivity to mumps, measles, chicken pox and having suffered infection or having been in contact with infected persons and between positivity to T. gondii and consuming red meat and / or street food (p > .05). Only in the case of Hepatitis B a significant difference between positivity and age (p = .001), the fact of being vaccinated (p = .001) and being sexually active (p = .004 was found. The percentage of vaccination in the study population was high only for He-patitis B (80%), while for the other infections it was 35.6% for rubella and measles, 22.2% for varicella and 10% for mumps. More than 82% of the students presented protection to the six agents studied and it is recommended to carry out constant sero-epidemiological surveys, to evaluate the immunization programs, to identify the risk groups and that people who do not present antibodies get vaccinated.

O probiótico Saccharomyces boulardii modula a resposta de IgG2a em camundongos expostos aos antígenos de Leishmania infantum / Probiotic Saccharomyces boulardii modulates IgG2a response in mice exposed to Leishmania infantum antigens

O objetivo do presente estudo foiavaliar os efeitos do probiótico Saccharomyces boulardii na modulação da resposta imune humoral de animais expostos a antígenos de Leishmania infantum. Para isso, 16 camundongos BALB/c foram imunizados com antígeno particulado de Leishmania infantum e divididos em dois grupos experimentais, um composto por animais suplementados e outro por animais não suplementados com o probiótico. Amostras de sangue dos animais foram colhidas semanalmente durante o período experimental e submetidas ao Ensaio da Imunoabsorbância Ligado à Enzima indireto para avaliação dos títulos de IgG totais e o perfil dos isotipos de IgG produzidos (IgG1 e IgG2a). A suplementação com o probiótico não exacerbou a produção de IgG total em comparação ao grupo controle, não havendo diferenças significativas entre os dois grupos. Porém, as soroconversões de IgG2a foram mais elevadas no grupo suplementado, no qual registrou-se um aumento de 1,46 vezes no final do experimento. Assim,a suplementação com S. boulardii foi capaz de modular a resposta de IgG2a/IgG1 nos animais expostos aos antígenos de Leishmania infantum.

The aim of the present study was to evaluate the effects of the Saccharomyces boulardii probiotic on the modulation of humoral immune response in animals exposed to Leishmania infantum antigens. For this, 16 BALB/c mice were immunized with Leishmania infantum particulate antigen and divided into two experimental groups, one consisting of supplemented animals and the other not probiotic supplemented animals. Blood samples from the animals were taken weekly during the experimental period and subjected to the Indirect Enzyme-Linked Immunosorbance Assay for evaluation of total IgG titers and the profile of the produced IgG isotypes (IgG1 and IgG2a). Probiotic supplementation did not exacerbate total IgG production compared to the control group, with no significant differences between the two groups. However, IgG2a seroconversions were higher in the supplemented group, which showed a 1.46-fold increase at the end of the experiment. Thus, supplementation with S. boulardii was able to modulate the IgG2a/IgG1 response in animals exposed to Leishmania infantum antigens.

Preliminary assessment of anti-α-Gal IgG and IgM levels in patients with patent Plasmodium vivax infection

Anti-α-Gal responses may exert a protective effect in falciparum malaria. However, the biological role of such antibodies is still unknown during Plasmodium vivax infections. We investigated IgG and IgM responses to α-Gal in individuals with vivax malaria. Anti-α-Gal IgG and IgM levels were higher in these patients than in controls, but no significant correlation was found between parasitaemia and anti-α-Gal response, nor between this response and ABO blood group status. This is the first study to investigate anti-α-Gal antibodies in P. vivax-infected patients; a larger survey is necessary to achieve a better understanding of host immune response during vivax malaria.

Anti-hepatitis B antibody levels In immunized medical students: are they at risk?

Abstract INTRODUCTION Medical students have an occupational risk for hepatitis B (HB). This study sought to determine anti-HBs and anti-HBc IgG levels in vaccinated students, check their seroconversion, and correlate this with vaccination. METHODS One hundred and forty-three students' blood samples and their vaccination schedules were analyzed. RESULTS: 65.7% were positive for anti-HBs; however, anti-HBs was absent in 34.3%. Only two samples were positive for anti-HBc IgG. CONCLUSIONS More than 30% of students did not have minimum protective levels. Comparing HBV vaccination and anti-HBs reactivity, the majority of reactive individuals received their last dose within the past 16 years.

Prevalencia de anticuerpos anti-Saccharomyces cerevisiae en pacientes celíacos / Prevalence of anti-Saccharomyces cerevisiae antibodies in celiac patients / Prevalência de anticorpos anti-Saccharomyces cerevisiae em pacientes celíacos

La enfermedad celíaca (EC) es una condición inflamatoria crónica del intestino delgado causada por intolerancia al gluten. El tratamiento consiste en la dieta libre de gluten (DLG). Los anticuerpos anti Saccharomyces cerevisiae (ASCA) están dirigidos contra la pared celular de la levadura, se asocian a enfermedades autoinmunes, y se propone la permeabilidad intestinal alterada como causa de activación de la inmunidad humoral. El objetivo del trabajo fue determinar la prevalencia de ASCA IgG e IgA en pacientes celíacos bajo tratamiento y evaluar la asociación de ASCA con el grado de adherencia a la DLG. Se analizaron 59 sueros de pacientes adultos celíacos con alta o baja adherencia a la DLG, y se determinó ASCA IgG e IgA. Se halló una prevalencia de ASCA IgG y/o IgA del 44%. Se encontró asociación entre ASCA-IgG y adherencia a DLG (OR 4,04 IC 95%: 1,32-12,38). La prevalencia de ASCA en la población celíaca estudiada es similar a la reportada en la bibliografía. La menor prevalencia de ASCA IgG en pacientes con una estricta DLG respecto de aquellos con baja adherencia, indicaría que su presencia depende del nivel de ingesta de gluten, sugiriéndolos como herramienta complementaria en el seguimiento del paciente celíaco.

Celiac disease (CD) is a chronic inflammatory condition of the small intestine caused by gluten intolerance. The treatment consists of gluten free diet (GFD). Anti Saccharomyces cerevisiae antibodies (ASCA) are directed against the cell wall of yeast, associated with autoimmune diseases, and an altered intestinal permeability is proposed as a cause of activation of humoral immunity. The objective of this work was to determine the prevalence of IgG and IgA ASCA in celiac patients under treatment and to evaluate the association of ASCA with the degree of adherence to GFD. Fifty-nine serum samples from adult celiac patients with high or low adherence to GFD were analyzed, determining IgG and IgA ASCA. A 44% prevalence of IgG and/or IgA ASCA was found. An association was discovered between IgG ASCA and GFD adherence (OR 4.04, 95% CI: 1.32-12.38). The prevalence of ASCA in the studied celiac population is similar to that reported in the literature. The lower prevalence of IgG ASCA in patients with a strict GFD compared to those with low adherence would indicate that their presence depends on the level of gluten intake, suggesting them as a complementary tool in the follow-up of the celiac patient.

A doença celíaca (DC) é uma condição inflamatória crônica do intestino delgado causada pela intolerância ao glúten. O tratamento consiste na dieta sem glúten (DSG). Os anticorpos anti Saccharomyces cerevisiae (ASCA) são dirigidos contra a parede celular da levedura, associados a doenças autoimunes, e à permeabilidade intestinal alterada como causa da ativação da imunidade humoral. O objetivo foi determinar a prevalência de ASCA IgG e IgA em pacientes celíacos em tratamento; avaliar a associação de ASCA com o grau de adesão ao DSG. Foram analisados 59 soros de pacientes celíacos adultos com alta ou baixa adesão ao DSG, determinando ASCA IgG e IgA. Foi encontrada uma prevalência de SCA IgG/ou IgA de 44%. Foi encontrada uma associação entre ASCA-IgG e a adesão ao DSG (OR 4,04 IC 95% 1,32-12,38). A prevalência de ASCA na população celíaca estudada é semelhante à relatada na literatura. A menor prevalência de ASCA IgG em pacientes com rigorosa DSG, em comparação àqueles com baixa adesão, indicaria que sua presença depende do nível de ingestão de glúten, sugerindo-os como uma ferramenta complementar no seguimento do paciente celíaco.

Anticuerpos de cadena única de alpaca para la detección de antígenos de Fasciola hepática / Single-chain antibodies from alpaca for the detection of Fasciola hepatica antigens

RESUMEN Objetivo. Producir anticuerpos recombinantes de cadena única de alpaca que se unan con alta afinidad y especificidad al antígeno excretado-secretado (ES) de Fasciola hepatica para el desarrollo de tecnologías nuevas de diagnóstico de fascioliasis humana y animal. Materiales y métodos. Se ha construido una genoteca de cADNde los dominios variables de anticuerpos de cadena única pesada, conocidos como VHH, a partir de células mononucleares de sangre periférica de una alpaca inmunizada con el antígeno ES de F. hepatica. La genoteca fue tamizada con el antígeno ES por despliegue diferencial de fagos (phage display), seleccionando diez VHH que se unen específicamente a ES. El VHH anti ES fue clonado en un vector de expresión, la proteína recombinante (VHH-ES1) de 15,3 kDa fue producida por fermentación en E. coli y purificada a homogeneidad por cromatografía de afinidad. La unión del VHH-ES1 al antígeno ES fue evaluada por ELISA usando VHH-ES1 como anticuerpo de captura, antisuero policlonal anti-ES de conejo y conjugado anti IgG de conejo con peróxidasa de rábano. Resultados. Se ha identificado y producido un VHH-ES1 recombinante que se une al antígeno ES (VHH-ES1) que correspondía a un anticuerpo de la subclase IgG2 de bisagra larga. La unión del anticuerpo VHH-ES1 al antígeno muestra linealidad respecto a la concentración de ES en el rango de 50-5000 ng/mL y el valor límite de detección del antígeno está en el rango de 30-170 ng/mL de ES (R2=0,99). Conclusión . El VHH-ES1 se une con afinidad y especificidad al antígeno ES de F. hepatica y es un anticuerpo promisorio a evaluar para el desarrollo de nuevas tecnologías de diagnóstico de fascioliasis.

ABSTRACT Objectives. To produce recombinant single-chain antibodies from alpaca that will bind to the excreted-secreted (ES) Fasciola hepatica antigen with high affinity and specificity, so as to develop new diagnostic technologies of human and animal fascioliasis. Materials and Methods. A gene bank of DNA of the variable dominions of heavy single-chain antibodies (VHH) has been created, based on mononuclear cells of peripheral blood of an alpaca immunized with the ES antigen of F. hepatica. The gene bank was screened with the ES antigen by differential phage display, selecting ten VHH that bind specifically to ES. The anti-ES VHH was cloned in an expression vector, the recombinant protein (VHH-ES1) of 15.3 kDa was produced by fermentation in E. coli and purified to homogeneity by affinity chromatography. The binding of VHH-ES1 to the ES antigen was evaluated by ELISA using VHH-ES1 as capture antibody, policlonal anti-ES serum of rabbit and conjugated rabbit anti IgG with radish peroxidase. Results. A VHH that binds to the ES antigen (VHH-ES1) has been identified through differential phage display and produced by fermentation in E. coli; this corresponds to an antibody of the long-hinge IgG2 subclass. The binding of the VHH-ES1 antibody to the antigen shows linearity with respect to the concentration of ES in the 50-5,000 ng/mL range and the limit of detection value of the antigen is in the 30-170 ng/mL range of ES (R2=0.99). Conclusions. The VHH-ES1 binds with affinity and specificity to the ES antigen of F. hepatica and is a promissory antibody to be assessed for the development of new fascioliasis diagnostic technologies.

Apresentação periorbitária de doença relacionada ao IgG4 / Periorbital presentation of IgG4 related disease

Resumo A doença relacionada ao IgG4 é uma condição imunomediada caracterizada pela presença de lesões com reação inflamatória associada à fibrose e à infiltração linfoplasmocitária rica em plasmócitos tissulares IgG4 positivos, compondo um espectro de doenças fibroproliferativas. A patogênese da DRIgG4 ainda é pouco compreendida e o tratamento é empírico. Relatamos o caso de um homem de 50 anos com lesões amareladas palpebrais associadas a edema local, diagnosticadas previamente como processo alérgico, até que biópsia com estudo imuno-histoquímico e dosagem de IgG4 sérico aventaram a hipótese de doença relacionada ao IgG4. Foi iniciado tratamento com corticoide e rituximabe, observando-se estabilização do quadro e sem apresentação de outras formas clínicas da doença.

Abstract IgG4-Related Disease is an immunomediated condition that is characterized by the presence of inflammatory lesions associated with fibrosis and lymphoplasmacytic infiltration rich in positive IgG4 tissue plasmocytes, forming a spectrum of fibroproliferative diseases. The pathogenesis of IgG4-RD is still poorly understood and the treatment is empirical. We report the case of a 50-year-old man with yellow eyelid lesions associated with local edema, previously diagnosed as an allergic process, until biopsy with immunohistochemical study and serum IgG4 dosage revealed the hypothesis of IgG4 related disease. Treatment with corticoid and rituximab was initiated, showing stabilization of the condition, without presenting other clinical forms of the disease.

Diagnostic significance of immunoglobulin G avidity in symptomatic and asymptomatic West Nile virus infection

Abstract INTRODUCTION West Nile virus (WNV) immunoglobulin M (IgM) antibodies have been shown to persist for up to 500 days in certain patients. To evaluate the usefulness of immunoglobulin G (IgG) avidity assessment in the diagnosis of WNV infection, we analyzed 54 WNV IgM- and/or IgG-positive serum samples from 39 patients with neuroinvasive disease and 15 asymptomatic cases tested during a seroprevalence investigation. METHODS Serological tests (WNV IgM/IgG antibody detection, IgG avidity) were performed using commercially available enzyme-linked immunosorbent assays. RESULTS WNV IgM antibodies were detected in 47 (87%) samples. Acute/recent WNV infection was confirmed based on low/borderline avidity index (AI) in 44 IgM-positive samples (93.6%). In three IgM-positive samples (6.4%), high IgG AIs were detected, thus indicating persisting IgM antibodies from previous infections. All IgM-negative samples showed high AIs. Patients with WNV neuroinvasive disease tested within 30 days showed low AIs. In six patients tested 34-50 days after disease onset, AI was borderline (42%-60%), suggesting earlier WNV IgG maturation. Samples with the highest IgM values were associated with the lowest AIs (Spearman's rho coefficient -0.767, p < 0.001). CONCLUSIONS Our results indicate that IgG avidity differentiates current/recent WNV infection from persistent IgM seropositivity from the previous WNV transmission season both in patients with WNV neuroinvasive disease and in asymptomatic persons. A strong negative correlation between IgM antibody levels and AI indicates that in cases with very high IgM levels, determination of IgG avidity may not be necessary. As many patients showed rapid avidity maturation, low IgG avidity is indicative of WNV infection within the previous month.

Immune humoral response of young lambs naturally infested by Oestrus ovis (Diptera: Oestridae) / Resposta imune humoral de cordeiros jovens naturalmente infestados por Oestrus ovis (Diptera: Oestridae)

Abstract Twenty-six newborn lambs were evaluated for 21 weeks, from birth to slaughter, to assess their plasma anti-Oestrus ovis immunoglobulin (IgG) using the ELISA technique. On the last day of sampling, all the lambs were slaughtered and O. ovis larvae were recovered, quantified and identified according to the larval stage. High levels of IgG were observed over the first three weeks of life, thus indicating that antibodies are transferred via colostrum from ewes to lambs. Afterwards, the antibody levels declined progressively until the lambs were 11 weeks of age and subsequently started to increase again when they were around 13 weeks of age, reaching the apex on the last week of sampling. All the lambs were parasitized with different larval stages of O. ovis, with an average of 39 larvae per lamb, and the intensity of the infestation ranged from 10 to 97 larvae. However, there was non-significant correlation coefficients between IgG levels and O. ovis larval burden (P > 0.05). In conclusion, although the lambs became infested with O. ovis at an early age, the larval burden was not associated with specific IgG levels.

Resumo Vinte e seis cordeiros recém-nascidos foram avaliados por 21 semanas, desde o nascimento até o abate, para avaliar os níveis plasmáticos de imunoglobulina (IgG) anti-Oestrus ovis utilizando-se a técnica de ELISA. No último dia de coleta, todos os cordeiros foram abatidos e as larvas de O. ovis foram recuperadas, quantificadas e identificadas de acordo com o estádio larval. Foram observados altos níveis de IgG nas primeiras três semanas de vida, indicando que os anticorpos são transferidos por meio do colostro das ovelhas para os cordeiros. Posteriormente, os níveis de anticorpos diminuíram progressivamente, até os cordeiros completarem 11 semanas de vida. Os níveis de IgG começaram a aumentar novamente a partir de 13 semanas de idade, atingindo o ápice na última semana de coleta. Todos os cordeiros estavam parasitados com diferentes estádios larvais de O. ovis com uma média de 39 larvas por cordeiro, e a intensidade da infestação variou de 10 a 97 larvas. Porém, não houve correlação significativa entre os níveis de IgG e a carga larval de O. ovis (P > 0,05). Em conclusão, embora os cordeiros tenham sido infestados com O. ovis ainda jovens, a carga larval não foi associada a níveis específicos de IgG.