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1.
Rev. bras. ginecol. obstet ; 43(12): 887-893, Dec. 2021. tab
Article in English | LILACS | ID: biblio-1357098

ABSTRACT

Abstract Objective The purpose of the present study is to standardize and evaluate the use of the immunoglobulin G (IgG) antibody avidity test on blood samples from newborns collected on filter paper to perform the heel test aiming at its implementation in ongoing programs. Methods Blood samples from newborns were collected on filter paper simultaneously with the heel prick test. All samples were subjected to immunoglobulin M IgM and IgG enzyme-linked immunosorbent assays (ELISA). Peripheral blood was collected again in the traditional way and on filter paper from newborns with high IgG levels (33). Three types of techniques were performed, the standard for measuring IgG in serum, adapted for filter paper and the technique of IgG avidity in serum and on filter paper. The results of the avidity test were classified according to the Rahbari protocol. Results Among the 177 samples, 17 were collected in duplicate from the same child, 1 of peripheral blood and 1 on filter paper. In this analysis, 1 (5.88%) of the 17 samples collected in duplicate also exhibited low IgG avidity, suggesting congenital infection. In addition, the results obtained from serum and filter paper were in agreement, that is, 16 (94.12%) samples presented high avidity, with 100% agreement between the results obtained from serum and from filter paper. Conclusion The results of the present study indicate that the avidity test may be another valuable method for the diagnosis of congenital toxoplasmosis in newborns.


Resumo Objetivo O objetivo do presente estudo é padronizar e avaliar a utilização do teste de avidez de anticorpos imunoglobulina G (IgG) em amostras de sangue de recémnascidos (RNs) coletadas em papel filtro para a realização do teste do pezinho visando a implementação nos programas já vigentes. Métodos Foram coletadas amostras de sangue de recém-nascidos em papel filtro simultaneamente ao teste do pezinho. Em todas as amostras, foram realizados os testes imunoenzimáticos (ELISA) imunoglobulina M (IgM) e IgG. Dos RNs que apresentaram altos índices de IgG (33), foi novamente coletado sangue periférico da forma tradicional e em papel filtro. Foram realizadas técnicas padrão para a dosagem de IgG em soro, adaptadas para papel filtro, e a técnica de avidez de IgG em soro e em papel filtro. Os valores obtidos para o teste de avidez foram classificados de acordo com o protocolo de Rahbari. Resultados Dentre as 177 recoletas, em 17 amostras foi realizada a coleta simultânea de sangue periférico e papel filtro da mesma criança. Nesta análise, 1 (5,88%) das 17 amostras coletadas em duplicata obteve também baixa avidez de IgG, sugerindo infecção congênita da criança, e houve concordância entre os resultados obtidos em soro e em papel filtro: 16 (94,12%) das amostras apresentaram alta avidez, com concordância de 100% entre os resultados obtidos em soro e em papel filtro. Conclusão Os dados do presente trabalho evidenciam que o teste de avidez poderá ser mais um método valioso a ser utilizado no diagnóstico da toxoplasmose congênita em RNs.


Subject(s)
Humans , Infant, Newborn , Toxoplasma , Immunoglobulin G , Toxoplasmosis, Congenital/diagnosis , Immunoglobulin M , Antibodies, Protozoan , Early Diagnosis
2.
Rev. chil. infectol ; 27(6): 499-504, dic. 2010. ilus, tab
Article in Spanish | LILACS | ID: lil-572912

ABSTRACT

Introduction: Toxoplasmosis (T) is a major chronic parasitic infection in immunocompromised patients and pregnant women. It is important to discriminate between acute phase (AT) and chronic phase (CT). Diagnosis is serological in immunocompetent patients (concentration of IgG and IgM). Objective: To evaluate the utility of an IgG avidity test (A-IgG) to identify the acute and chronic stage. Avidity is the strength of affinity between a specific immunoglobulin and the protein antigenic epitope of the infecting agent, an affinity that increases over time. Patients and Methods: We used a qualitative kit that measures the avidity of IgG, discriminating the two phases. In 35 patients with clinical diagnosis of AT and/or CT, IgG, IgM and IgG A (VIDAS®) were performed. Results: Patients with AT were positive for IgM and IgG, but presented weak avidity. In the 21 cases with CT, 52 percent (n: 11) were IgM positive and 100 percent (n: 21) had positive IgG with strong avidity. Discussion: The results confirm that the test of A-IgG may be useful in the diagnosis of AT, and has 100 percent concordance with reference test (qualitative IgM + quantitative IgG). The result is available within 24 hrs, and may be useful in diagnosis of AT in pregnant women.


Introducción: Toxoplasmosis (T) es una infección parasitaria crónica importante en pacientes inmunocompro-metidos y mujeres embarazadas. Es relevante discriminar entre fase aguda (TA) y fase crónica (TC). Su diagnóstico es serológico en inmunocompetentes (detección de IgG e IgM). Objetivo: Evaluar la utilidad del test de avidez IgG (A-IgG) para identificar la fase aguda y o crónica. Avidez es la fuerza de afinidad entre una inmunoglobulina específica y el epítope de la proteína antigénica del agente infectante, afinidad que aumenta con el tiempo. Pacientes y Métodos: Se usó un test cualitativo que mide la avidez de IgG, discriminando las dos fases. A 35 pacientes con diagnóstico clínico de TA y o TC, se les realizó IgG, IgM e A-IgG en Equipo VIDAS®. Resultados: Los pacientes con TA fueron positivos para IgM e IgG y presentaron avidez débil. Los 21 casos con TC 52 por ciento (n: 11) tuvieron IgM positivo y 100 por ciento (n: 21) tuvo IgG positiva con avidez fuerte. Discusión: Los resultados confirman que el test de A-IgG puede ser de gran utilidad en el diagnóstico de TA, concordancia: 100 por ciento con test de referencia (IgM cualitativa + IgG cuantitativa). El resultado está disponible en menos de 24 hrs, pudiendo ser útil en el diagnóstico de TA en mujeres embarazadas.


Subject(s)
Adolescent , Adult , Child , Female , Humans , Infant, Newborn , Male , Pregnancy , Young Adult , Antibodies, Protozoan/immunology , Antibody Affinity/immunology , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Reagent Kits, Diagnostic , Toxoplasma/immunology , Toxoplasmosis/diagnosis , Acute Disease , Antibodies, Protozoan/blood , Chronic Disease , Immunoglobulin G/blood , Immunoglobulin M/blood , Pregnancy Complications, Parasitic/diagnosis , Pregnancy Complications, Parasitic/immunology , Toxoplasmosis/immunology
3.
Rev. Soc. Bras. Med. Trop ; 41(6): 628-634, Nov.-Dec. 2008. ilus, graf, tab
Article in Portuguese | LILACS | ID: lil-502045

ABSTRACT

Para verificar a ocorrência da toxoplasmose em Cascavel, Paraná, cidade próxima a região onde ocorreu o maior surto epidêmico descrito mundialmente, 334 amostras de soros de gestantes foram triadas pelo ensaio imunoenzimático comercial IgG no Laboratório Municipal de Cascavel, e confirmadas no Instituto de Medicina Tropical de São Paulo por imunofluorescência IgG, ensaio imunoenzimático e avidez de IgG in house. A soropositividade pelo IgG comercial foi 54,2 por cento, pela imunofluorescência 54,8 por cento e pelo IgG in house 53,9 por cento, com boa concordância entre imunofluorescência/IgG comercial (Kappa=0,963781; co-positividade=97,8 por cento; co-negatividade=98,7 por cento) e imunofluorescência/IgG in house (Kappa=0,975857; co-positividade=97,8 por cento; co-negatividade=100 por cento). A evidência de infecção aguda nas gestantes foi similar tanto pela avidez de IgG (2,4 por cento ao ano) como pela análise estatística de tendência (teste χ2) por faixa etária (2 por cento ao ano), sugerindo que a triagem sorológica pré-natal e a vigilância epidemiológica são imprescindíveis para redução do risco da toxoplasmose na região, embora sem evidência de surto epidêmico.


In order to investigate the incidence of toxoplasmosis in Cascavel, Paraná, a city near the region where the largest reported epidemic outbreak in the world occurred, 334 serum samples from pregnant women were screened using a commercial IgG immunoenzymatic assay at the Municipal Laboratory in Cascavel and were confirmed at the Institute of Tropical Medicine in São Paulo, by means of IgG immunofluorescence, immunoenzymatic assaying and the in-house IgG avidity test. The IgG seropositivity from the commercial test was 54.2 percent, from immunofluorescence 54.8 percent and from the in-house IgG 53.9 percent, with good agreement between immunofluorescence and the commercial IgG test (kappa = 0.963781; co-positivity = 97.8 percent; co-negativity = 98,7 percent) and between immunofluorescence and the in-house IgG (kappa = 0.975857; co-positivity = 97.8 percent; co-negativity = 100 percent). The evidence of acute infection among the pregnant women was similar, as estimated both by IgG avidity (2.4 percent/year) and by statistical trend analysis (χ2 test) according to age group (2 percent/year). This suggests that prenatal serological screening and epidemiological surveillance are essential for reducing the risk of toxoplasmosis in the region, although without evidence of an epidemic outbreak.


Subject(s)
Adolescent , Adult , Animals , Female , Humans , Pregnancy , Young Adult , Antibodies, Protozoan/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Pregnancy Complications, Parasitic/epidemiology , Toxoplasma/immunology , Toxoplasmosis/epidemiology , Acute Disease , Antibody Affinity , Brazil/epidemiology , Cross-Sectional Studies , Enzyme-Linked Immunosorbent Assay , Fluorescent Antibody Technique, Indirect , Prevalence , Pregnancy Complications, Parasitic/diagnosis , Sensitivity and Specificity , Toxoplasmosis/diagnosis , Young Adult
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