Evaluation of chimeric recombinant antigens for the serodiagnosis of Trypanosoma cruzi in dogs: a promising tool for Chagas disease surveillance.

BACKGROUND: Chagas disease (CD), a neglected parasitic disease caused by Trypanosoma cruzi, poses a significant health threat in Latin America and has emerged globally because of human migration. Trypanosoma cruzi infects humans and over 100 other mammalian species, including dogs, which are important sentinels for assessing the risk of human infection. Nonetheless, the serodiagnosis of T. cruzi in dogs is still impaired by the absence of commercial tests. In this study, we investigated the diagnostic accuracy of four chimeric recombinant T. cruzi IBMP antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) for detecting anti-T. cruzi antibodies in dogs, using latent class analysis (LCA). METHODS: We examined 663 canine serum samples, employing indirect ELISA with the chimeric antigens. LCA was utilized to establish a latent variable as a gold standard for T. cruzi infection, revealing distinct response patterns for each antigen. RESULTS: The IBMP (Portuguese acronym for the Molecular Biology Institute of Paraná) antigens achieved area under the ROC curve (AUC) values ranging from 90.9% to 97.3%. The highest sensitivity was attributed to IBMP-8.2 (89.8%), while IBMP-8.1, IBMP-8.3, and IBMP-8.4 achieved 73.5%, 79.6%, and 85.7%, respectively. The highest specificity was observed for IBMP-8.4 (98.6%), followed by IBMP-8.2, IBMP-8.3, and IBMP-8.1 with specificities of 98.3%, 94.4%, and 92.7%, respectively. Predictive values varied according to prevalence, indicating higher effectiveness in endemic settings. CONCLUSIONS: Our findings underscore the remarkable diagnostic performance of IBMP-8.2 and IBMP-8.4 for the serodiagnosis of Trypanosoma cruzi in dogs, representing a promising tool for the diagnosis of CD in dogs. These chimeric recombinant antigens may not only enhance CD surveillance strategies but also hold broader implications for public health, contributing to the global fight against this neglected tropical disease.

Precision arbovirus serology with a pan-arbovirus peptidome.

Arthropod-borne viruses represent a crucial public health threat. Current arboviral serology assays are either labor intensive or incapable of distinguishing closely related viruses, and many zoonotic arboviruses that may transition to humans lack any serologic assays. In this study, we present a programmable phage display platform, ArboScan, that evaluates antibody binding to overlapping peptides that represent the proteomes of 691 human and zoonotic arboviruses. We confirm that ArboScan provides detailed antibody binding information from animal sera, human sera, and an arthropod blood meal. ArboScan identifies distinguishing features of antibody responses based on exposure history in a Colombian cohort of Zika patients. Finally, ArboScan details epitope level information that rapidly identifies candidate epitopes with potential protective significance. ArboScan thus represents a resource for characterizing human and animal arbovirus antibody responses at cohort scale.

Comparative Evaluation of Select Serological Assays for Zika Virus Using Blinded Reference Panels.

In response to the 2015 Zika virus (ZIKV) epidemic that occurred in Brazil, numerous commercial serological assays have been developed for clinical and research applications. Diagnosis of recent infection in pregnant women remains challenging. Having standardized, comparative studies of ZIKV tests is important for implementing optimal diagnostic testing and disease surveillance. This is especially important for serology tests used to detect ZIKV infection given that antibodies against ZIKV can cross-react with other arboviruses in the same virus family, such as dengue virus (DENV), yellow fever virus (YFV) and West Nile virus (WNV). We looked at the sensitivity and specificity of tests detecting ZIKV antibodies (IgM, IgG) from multiple manufacturers using panels of samples previously collected with known exposure to ZIKV and other arboviruses. We found that performance of the IgM tests was highly variable, with only one test (Inbios 2.0 IgM capture ELISA) having both high sensitivity and specificity. All IgG tests showed good sensitivity; however, specificity was highly variable, with some assays giving false-positive results on samples infected by another flavivirus. Overall, the results confirmed that accurate ZIKV antibody testing is challenging, especially in specimens from regions endemic for multiple other flaviviruses, and highlight the importance of available and suitable reference samples to evaluate ZIKV diagnostics.

Improved serodiagnosis of Trypanosoma vivax infections in cattle reveals high infection rates in the livestock regions of Argentina.

Bovine trypanosomosis, caused by Trypanosoma vivax, currently affects cattle and has a significant economic impact in sub-Saharan Africa and South America. The development of new diagnostic antigens is essential to improve and refine existing methods. Our study evaluated the efficacy of two recombinant antigens in detecting specific antibodies in cattle. These antigens are derivatives of an invariant surface glycoprotein (ISG) from T. vivax. A fraction of a previously described antigen (TvY486_0045500), designated TvISGAf, from an African strain was evaluated, and a new ISG antigen from an American isolate, TvISGAm, was identified. The two antigens were expressed as fusion proteins in Escherichia coli: TvISGAf was fused to the MBP-His-tag, and TvISGAm was obtained as a His-tag fused protein. An ELISA evaluation was conducted using these antigens on 149 positive and 63 negative bovine samples. The diagnostic performance was enhanced by the use of a combination of both antigens (referred to as TvISG-based ELISA), achieving a sensitivity of 89.6% and specificity of 93.8%. Following the validation of the TvISG-based ELISA, the seroprevalence of T. vivax infection in 892 field samples from cattle in the central region of Argentina was determined. The mean seroprevalence of T. vivax was 53%, with variation ranging from 21% to 69% among the six departments studied. These results support the use of the TvISG ELISA as a valuable serological tool for the detection and monitoring of T. vivax infection in cattle. Furthermore, we report for the first time the seroprevalence of T. vivax in Argentina, which highlights the widespread endemic nature of the disease in the region. In order to effectively manage the increasing spread of T. vivax in the vast livestock production areas of South America, it is essential to implement consistent surveillance programs and to adopt preventive strategies.

Advancing serologic diagnosis: assessing the efficacy of rErpY-like protein in human leptospirosis detection.

Leptospirosis is a globally distributed infectious disease caused by pathogenic spirochetes of the Leptospira genus, often overlooked. It is estimated that the disease affects approximately one million people annually, resulting in more than 58,900 deaths. The gold standard for serodiagnosis of leptospirosis is the Microscopic Agglutination Test (MAT). However, the limitations of this technique necessitate the exploration of alternative diagnostic methods. In this study, we evaluated the ErpY-like recombinant protein (rErpY-like) in the development of a serologic diagnostic assay for human leptospirosis. Eighty-six human sera samples, characterized by MAT, underwent evaluation through indirect IgM-ELISA and IgG-ELISA. The sensitivity and specificity values obtained from IgM-ELISA were 60% and 76%, respectively, while those from IgG-ELISA were 96.4% and 100%, respectively. The use of the rErpY-like protein in both IgM-ELISA and IgG-ELISA proves to be a sensitive and specific method for antibody detection. This could potentially serve as a valuable alternative tool in the diagnosis of human leptospirosis.

The use of peptides for immunodiagnosis of human Chagas disease.

Chagas disease, caused by the protozoa Trypanosoma cruzi, continues to be a serious public health problem in Latin America, worsened by the limitations in its detection. Given the importance of developing new diagnostic methods for this disease, the present review aimed to verify the number of publications dedicated to research on peptides that demonstrate their usefulness in serodiagnosis. To this end, a bibliographic survey was conducted on the PubMed platform using the keyword "peptide" or "epitope" combined with "Chagas disease" or "Trypanosoma cruzi"; "diagno*" or "serodiagnosis" or "immunodiagnosis", without period restriction. An increasing number of publications on studies employing peptides in ELISA and rapid tests assays was verified, which confirms the expansion of research in this field. It is possible to observe that many of the peptides tested so far originate from proteins widely used in the diagnosis of Chagas, and many of them are part of commercial tests developed. In this sense, as expected, promising results were obtained for several peptides when tested in ELISA, as many of them exhibited sensitivity and specificity values above 90%. Furthermore, some peptides have been tested in several studies, confirming their diagnostic potential. Despite the promising results observed, it is possible to emphasize the need for extensive testing of peptides, using different serological panels, in order to confirm their potential. The importance of producing an effective assay capable of detecting the clinical stages of the disease, as well as new immunogenic antigens that enable new serological diagnostic tools for Chagas disease, is evident.

Comparison of two serological diagnosis tests for bovine paratuberculosis.

Mycobacterium avium subsp. paratuberculosis (MAP) is the causal agent of paratuberculosis (PTBC), a chronic infectious granulomatous enteritis of ruminants. The PTBC diagnosis with commercial ELISA has limitations in sensitivity and specificity, and its results depend on the state of progress of the disease. This research aimed to evaluate two different ELISAs: (a) an "in-house" ELISA with a sonicated antigen obtained from a MAP I47 strain, and (b) a commercial ELISA. In total, the evaluated sample consisted of 394 bovine serum samples from 12 farms in Argentina with high (5-9%) and low (≤ 0.05%) prevalence of PTBC. The evaluation of the new antigen (2.5 µg/mL) was against a 1:50 dilution of the M. phlei faced sera. The cut-off point, sensitivity, and specificity determinations of both techniques were by ROC curve analysis. The area under the curve for the I47 ELISA was 0.9 (CI 95%, 0.93-0.97). With a cut-off point of 8.8%, the sensitivity was 84.3% and the specificity 96.6%. The agreement between both techniques was 0.7 (CI 95%, 0.6-0.8). These results indicate a high discriminative capacity to differentiate positive and negative bovine sera of MAP infection with the I47 ELISA. This result would represent an advantage to dispense with the imported kit.

Diagnosis of fasciolosis antibodies in Brazilian cattle through ELISA employing both native and recombinant antigens.

Bovine fasciolosis is a parasitic disease with a global reach. Coprological based on egg detection in fecal samples and liver inspection to evaluate the presence of the parasite is currently the gold standard for diagnosing chronic fasciolosis in cattle. However, these techniques are labor-intensive and ineffective during the acute phase of the disease. Serodiagnosis using native and recombinant antigens has become an interesting alternative in efforts to identify cattle fasciolosis. We evaluated cattle from abattoir (n = 139) and farms (n = 500) through liver inspection and coprological examination, respectively. Our laboratory team optimized and validated enzyme-linked immunosorbent assay tests based on somatic antigen, excretory/secretory proteins, and the recombinant antigen cathepsin L-1 to detect serum antibodies against fasciolosis in cattle. For animals from abattoir, 10 were positive for fasciolosis according to liver inspection. Both FhES and FhrCL-1 presented an area under the receiver operating characteristic (AUROC) curve of 0.80, with a sensitivity of 0.80 (95% CI: 0.46-0.95) and 0.70 (95% CI: 0.38-0.90) and specificity of 0.81 (95% CI: 0.73-0.87) and 0.87 (95% CI: 0.80-0.92), respectively. For those cattle from farms, 28 were positive only for fasciolosis according to coprological examination. In this scenario, FhES gave the best performance, with an AUROC of 0.84, sensitivity of 0.79 (95% CI: 0.60-0.90), and specificity of 0.86 (95% CI: 0.82-0.89). In conclusion, our study highlights the potential of serodiagnosis for accurately screening cattle fasciolosis. The promising sensitivity and specificity values of FhES when compared to liver inspection or coprological examination enhance its importance for cattle fasciolosis diagnosis. IMPORTANCE: The aim of this article was to identify antibodies against fasciolosis in cattle in Brazil. The methodology was reproduced in our laboratory and applied for the first time to the Brazilian cattle herd. The antigens tested can be used as a screening test and thus speed up the diagnosis of bovine fascioliasis.

Diagnosis of Canine Visceral Leishmaniasis by Flow Cytometry Serology using the rMELEISH Multiepitope Antigen Coupled in a Functional Bead.

BACKGROUND: Visceral leishmaniasis (VL) is a zoonotic disease, with dogs being the main reservoir of the Leishmania infantum parasite. OBJECTIVE: To develop a new flow cytometry test to diagnosis canine VL (CVL) diagnosis. METHODS: The current study addresses a new flow cytometry test using beads coupled to the multiepitope antigen rMELEISH. RESULTS: In the study set of samples a sensitivity (87.1%) and specificity (89.9%) was observed. Considering the dogs' clinical status, 20/20 (100.0%) of the symptomatic sera tested positive, while 19/22 (86.4%) of the oligosymptomatic and 16/20 (80.0%) of asymptomatic were positive. In the non-infected control, all samples (0/30) tested as negative. In the cross-reaction control, the test was more efficient in dogs infected with L. braziliensis (2/10) and Trypanosoma cruzi (0/10), than those with Babesia canis (4/10) and Ehrlichia canis (4/10). Dogs immunized with different vaccines (Leishmune, Leish-Tec®, or LBSap) did not present serological reactivity. CONCLUSION: The flow cytometry serology through coupling the antigen rMELEISH in functional beads showed high accuracy in diagnosing CVL.

Use of recombinant malate dehydrogenase (MDH) and superoxide dismutase (SOD) [CuZn] as antigens in indirect ELISA for diagnosis of bovine brucellosis.

The objective of this study was to validate an indirect enzyme-linked immunoassay (iELISA) using the recombinant proteins, malate dehydrogenase (MDH) and superoxide dismutase (SOD) [CuZn], as antigens and to evaluate its ability to discriminate antibodies produced by vaccination from those induced by infection in the diagnosis of bovine brucellosis. Sera from six groups were evaluated: G1 - culture-positive animals (52 serum samples) (naturally infected); G2 - non-vaccinated animals (28 serum samples) positive in RBT (Rose Bengal test) and 2ME (2-mercaptoethanol test) selected from brucellosis-positive herds; G3 - animals from a brucellosis-free area (32 serum samples); G4 - S19 vaccinated heifers (114 serum samples); G5 - RB51 vaccinated heifers (60 serum samples); G6 - animals inoculated with inactivated Yersinia enterocolitica O:9 (42 serum samples). Diagnostic sensitivity (DSe) and diagnostic specificity (DSp) were estimated using the frequentist approach and the confidence interval (CI) (95%) calculated by the Clopper-Pearson (exact) method. The DSe for iELISA_MDH in the G1 group was 71.7% (CI 95%: 57.6-83.2%) and for the G2 100.0% (CI 95%: 87.7-100.0%), whereas the DSp was 84.4% in the G3 (CI 95%: 67.2-94.7%). For the iELISA_SOD the DSe was estimated 67.3% for the G1 (CI 95%: 52.9-79.7%) and 71.4% for G2 (CI 95%: 51.3-86.8%), while the DSp for G3 was 87.5% (CI 95%: 71.0-96.5%). iELISA_MDH and iELISA_SOD showed potential to be used in the diagnosis of infected animals, increasing the range of serological tests available for the diagnosis of bovine brucellosis, with the advantage of being S-LPS-free. However, none of the tests could differentiate between infection and vaccination.

Immunogenic mapping of rDyn-1 and rKDDR-plus proteins and selection of oligopeptides by immunoblotting for the diagnosis of Leishmania infantum-infected dogs.

Endemic in Brazil, visceral leishmaniasis (VL) is a zoonotic infection that is among the most important parasitic diseases transmitted by vectors. Dogs are the main reservoirs of canine leishmaniasis (CanL) and their identification is used in some countries as part of disease prevention and control measures in the canine and human population. In this context, serological tests are necessary, composed of antigens capable of correctly identifying infected dogs, minimizing the number of false-negative cases. This study aimed to identify more immunoreactive peptides derived from two previously described whole proteins (rDyn-1 and rKDDR-plus) and compare their performance to the control antigens rK39 and the crude extract for the detection of dogs infected with L. infantum, especially the asymptomatic ones. The three selected peptides and a mixture of them, along with the rDyn-1, rKDDR-plus, rK39, and crude extract antigens were evaluated using indirect ELISA with sera samples from 186 dogs with CanL, being asymptomatic (n = 50), symptomatic (n = 50), co-infected (n = 19), infected with Babesia sp. (n = 7), Ehrlichia sp. (n = 6), T. cruzi (n = 20) and uninfected (n = 34). The results showed that the rDyn-1 protein and the peptide mixture had the highest sensitivity (100% and 98.32%, respectively) and specificity (97.01 and 98.51, respectively). A high degree of kappa agreement was found for rDyn-1 protein (0.977), mixed peptides (0.965), rKDDR-plus protein (0.953), K-plus peptide 1 (0.930) and Dyn-1 peptide (0.893). The mixture of peptides showed the highest likelihood (65.87). The ELISA using the mixture of peptides and the rDyn-1 protein showed high performance for CanL serodiagnosis. More mix combinations of the peptides and additional extended field tests with a larger sample size are recommended.

Production and Characterization of Two Specific ZIKV Antigens Based on Bioinformatic Analysis and Serological Screening.

BACKGROUND: The high structural similarity between the Zika virus (ZIKV) and other flaviviruses, such as Dengue Virus (DENV), complicates the identification of the infecting virus due to the occurrence of cross-reactions in serological assays. This phenomenon has increased the demand for more specific antigens for immunodiagnostic applications. METHODS: The present work aimed to identify specific regions of ZIKV and produce unique antigens through computational methods, molecular and microbiological techniques. RESULTS: Based on the computational analysis we successfully expressed two recombinant proteins derived from specific regions of the ZIKV. Through serological assays using characterized sera, we observed that the region 146-182 of ZIKV's E protein, expressed in tandem, was not reactive despite the predictive sensitivity and specificity observed by computer analyses. On the other hand, the non-denatured fraction 220-352 of ZIKV's NS1 showed greater specificity to IgG+ sera of ZIKV by dot blot and western blot, which highlights its properties as a possible tool in the diagnosis of ZIKV. CONCLUSION: These findings demonstrate that ZIKV NS1 fraction 220-352 is a potential tool that may be applied in the development of serological diagnosis. We also provided data that suggest the non-applicability of the region 146-182 of ZIKV's protein E in serological assays despite previous indications about its potential based on computational analysis.

Teste de antigliadina deaminada IgG para crianças com até 2 anos de idade e com suspeita de doença celíaca / IgG deaminated antigliadin test for children aged 2 years or older with suspected celiac disease

INTRODUÇÃO: A Doença Celíaca (DC) é uma doença autoimune crônica do intestino delgado caracterizada por intolerância permanente ao glúten. A sua prevalência global é de aproximadamente 1%. No Brasil, essa prevalência foi relatada em cerca de 0,54% em crianças (1-14 anos). O rastreamento por sorologia associado à confirmação por biópsia duodenal é padrão ouro para o diagnóstico em adultos e em crianças, mas a biópsia precisa ser bem indicada na prática pediátrica por ser um procedimento invasivo e potencialmente de alto risco. Os testes sorológicos para detectar anticorpos IgA são comumente utilizados, porém indivíduos com deficiência de IgA não podem ser diagnosticados/rastreados por esses testes, justamente porque apresentam déficit na síntese de todas as imunoglobulinas do tipo A. Uma alternativa de triagem para esses indivíduos, bem como para os menores de 2 anos, é a dosagem sérica dos anticorpos IgG, como o teste antigliadina deaminada IgG. PERGUNTA DE PESQUISA: O uso do teste sorológico antigliadina deaminada IgG para triagem é mais acurado e custo-efetivo em pacientes com deficiência de IgA e suspeita de doença celíaca e crianças menores de dois anos quando comparado à triagem com antitransglutaminase IgA e confirmação por biópsia de duodeno por via endoscópica (endoscopia digestiva alta + biópsia)? EVIDÊNCIAS CIENTÍFICAS: Este relatório incluiu oito estudos que avaliaram se o uso do teste sorológico antigliadina deaminada IgG é mais acurado em pacientes com deficiência de IgA e suspeita de doença celíaca de qualquer idade e crianças menores de dois anos quando comparado à biópsia de duodeno por via endoscópica para diagnóstico da doença celíaca. Segundo os resultados das metanálises apresentadas neste relatório, para as análises da acurácia obtidas por meio da sensibilidade e especificidades combinadas, destaca-se a boa especificidade do teste antigliadina deaminada IgG em crianças menores de dois anos, utilizando o ponto de corte determinado pelo fabricante (97,8%; IC95% 95,6% - 98,9%). Já a especificidade combinada foi máxima (100,0%; IC95%:0,0 - 100,0%), potencializando o valor preditivo negativo do teste antigliadina deaminada IgG neste grupo populacional. Estes achados mostram que a adição do teste antigliadina deaminada IgG pode melhorar a acurácia diagnóstica da detecção de DC em crianças menores de dois anos de idade. AVALIAÇÃO ECONÔMICA (AE): Conduziu-se análise de custo-efetividade para comparar os testes diagnósticos com base em suas efetividades e seus custos, por meio da razão de custoefetividade incremental (RCEI). Considerando-se as diferenças observadas no desempenho do teste para crianças menores de dois anos e indivíduos com deficiência de IgA e suspeita de doença celíaca, foram propostas duas árvores de decisão. No caso de indivíduos com deficiência de IgA, a realização de teste antigliadina deaminada associada à EDA com biópsia, comparada à antigliadina deaminada isolada resultaria em razão de custo-efetividade incremental (RCEI) de R$ 108,17 por biópsia evitada. Para a comparação entre antigliadina deaminada isolada e EDA com biópsia, a RCEI seria de R$ 2.063,16 por biópsia evitada. ANÁLISE DE IMPACTO ORÇAMENTÁRIO (AIO): Considerando a população elegível total e suspeita de doença celíaca, o cenário alternativo 01 (market share variando de 30% a 50%) provocaria uma economia de R$ 30.671.133,25, no caso da incorporação do teste antigliadina em substituição aos testes atuais. Já o cenário alternativo 02 (market share de 50% a 70%) de substituição dos testes atuais pelo teste da antigliadina provocaria também economia de R$ 46.018.687,48. Já no cenário em que o teste antigliadina seja adicionado aos testes atuais, ao invés de substituí-los, o impacto orçamentário acumulado em cinco anos seria de R$ 14.410.515,92. CONSIDERAÇÕES FINAIS: Segundo os resultados das metanálises apresentadas neste relatório, destaca-se a boa especificidade do teste de antigliadina deaminada IgG em crianças menores de dois anos, utilizando o ponto de corte determinado pelo fabricante (97,8%; IC95% 95,6% - 98,9%). Já a especificidade combinada foi máxima (100,0%; IC95%:0,0 ­ 100,0%), potencializando o valor preditivo negativo do teste de antigliadina deaminada IgG neste grupo populacional. Para a população de indivíduos com deficiência de IgA, a sensibilidade combinada foi de 76,7% (IC 95%: 54,7% a 90,0%) e a especificidade de 73,3% (IC 95%: 60,6% a 83,0%). A taxa de falsos positivos global correspondeu a 26,7% (IC 95%: 17,0% a 39,4%). Contudo, os achados devem ser interpretados com cautela, uma vez que os estudos primários incluídos foram considerados de qualidade metodológica baixa e muito baixa qualidade da evidência. Um dos estudos incluídos neste relatório é uma revisão sistemática cujo divergiu do encontrado na meta-análise feita pelo grupo elaborador. Enquanto a sensibilidade para o teste antigliadina deaminada IgG em relação à biópsia duodenal foram de 0,96 (IC 95% 0,91 a 0,98) na revisão sistemática, a metaanálise deste relatório teve como resultado 0,48 (IC de 95%: 0,23 a 0,97). Essa divergência está relacionada ao ponto de corte utilizado para a inclusão dos estudos nas metaanálises. Em relação à confiança nos resultados da revisão sistemática em questão, os resultados estão associados a uma baixa confiabilidade. RECOMENDAÇÃO PRELIMINAR DA CONITEC: O tema foi avaliado na 113ª Reunião Ordinária da Conitec em 5 de outubro de 2022. A recomendação inicial foi desfavorável à incorporação do teste de antigliadina deaminada IgG para pessoas com deficiência de IgA por considerar que os testes atualmente disponíveis no SUS já atendem satisfatoriamente a população. Ademais, a recomendação inicial foi favorável à incorporação do teste de antigliadina deaminada IgG para pessoas menores de 2 anos de idade por evitar as hospitalizações necessárias para realização de endoscopia digestiva alta nessa população. CONSULTA PÚBLICA: Foram recebidas 18 contribuições, sendo cinco pelo formulário para contribuições técnico-científicas e 13 pelo formulário para contribuições sobre experiência ou opinião de pacientes, familiares, amigos ou cuidadores de pacientes, profissionais de saúde ou pessoas interessadas no tema. Em relação às contribuições de cunho técnico-científico, quatro concordaram que o teste antigliadina deaminada IgG deve ser incorporado ao SUS e uma não concordou. A Federação Nacional das Associações de Celíacos do Brasil (FENACELBRA) se manifestou contrária à recomendação de incorporação do teste diagnóstico e a favor de seguir a Sociedade Europeia de Gastroenterologia, Hepatologia e Nutrição Pediátrica (ESPGHAN), que sugere que seja realizada a dosagem de IgA total e antitransglutaminase IgA (antitTG) enquanto o paciente estiver consumindo glúten diariamente por cerca de 2 a 3 meses. No caso de crianças com concentração de IgA baixa, a contribuição indicou a necessidade de uma das seguintes sorologias IgG: antigliadina deaminada IgG, antiendomísio IgG ou antitransglutaminase IgG. Um participante foi contrário à premissa de que o resultado para o teste antigliadina deaminada IgG positivo deveria substituir a endoscopia e biópsia, o que foi corroborado por um especialista que participou do grupo elaborador. Dessa forma, uma avaliação econômica e análise de impacto orçamentário adicional foram realizadas com o objetivo de avaliar o impacto dessa premissa. A AE resultou numa RCEI custo-efetiva (R$ 1.254 por QALY ganho) e a AIO resultou em impacto orçamentário positivo de R$ 17.460.094 ao longo de cinco anos. Quanto às contribuições referentes ao formulário de experiência ou opinião, todos foram favoráveis à incorporação. RECOMENDAÇÃO FINAL DA CONITEC: As contribuições da consulta pública foram apresentadas à Conitec por ocasião da 117ª Reunião Ordinária, realizada em 29 de março de 2023. Os membros presentes deliberaram, por unanimidade, recomendar a incorporação do teste de antigliadina deaminada IgG para crianças com até 2 anos de idade e com suspeita de doença celíaca, porque, para essa população, o teste anti-gliadina tem alta acurácia diagnóstica, enquanto para os deficientes de IgA a acurácia diagnóstica foi considerada moderada e de impacto clínico incerto. O teste anti-gliadina deaminada IgG para crianças de até 2 anos de idade deverá ser incorporado conforme Protocolo Clínico do Ministério da Saúde. Por fim, foi assinado o Registro de Deliberação Nº 811 / 2023. DECISÃO: ncorporar, no âmbito do Sistema Único de Saúde - SUS, o teste de antigliadina deaminada IgG para crianças com até 2 anos de idade e com suspeita de doença celíaca, publicada no Diário Oficial da União nº 74, seção 1, página 195, em 18 de abril de 2023.

Celiaquía: Aprovechar el poder diagnóstico de los anticuerpos / Celiac disease: harnessing the diagnostic power of antibodies

La celiaquía es un trastorno mediado por la respuesta inmune al gluten ingerido en individuos genéticamente susceptibles. La enfermedad celíaca afecta al 1 por ciento de la población mundial, y su incidencia se ha incrementado sustancialmente en las últimas décadas. Sin embargo, aún la enfermedad celíaca es pobremente reconocida por la comunidad médica y por la población, tanto a nivel internacional, como nacional, muchos casos permanecen subdiagnosticados. Para mejorar el diagnóstico y manejo del paciente celíaco se recomienda el uso oportuno de la serología específica de la enfermedad celíaca. De los distintos anticuerpos asociados con la enfermedad celíaca, los anticuerpos anti-transglutaminasa tisular (anti-TGt IgA) representan la primera opción diagnóstica por su elevada sensibilidad y especificidad. La prueba de anti-TGt IgA no solo permite descartar de modo confiable la celiaquía, sino funciona como filtro para la selección de pacientes tributarios de biopsia intestinal para la confirmación diagnóstica. El desarrollo de la serología ha posibilitado la aplicación de nuevas estrategias diagnósticas que obvian la biopsia intestinal al menos en algunos grupos de pacientes(AU)

Celiac disease is a disorder mediated by the immune response to ingested gluten in genetically susceptible individuals. Celiac disease affects 1percent of the world population, and its incidence has increased substantially in recent decades. However, celiac disease is still poorly recognized by the medical community and by the population, both domestic and international, many cases remain underdiagnosed. Improving the diagnosis and management of the celiac patient, the timely use of specific serology for celiac disease is recommended. Different antibodies associated with celiac disease, however, anti-tissue transglutaminase antibodies (anti-TGt IgA) represent the first diagnostic option due to their high sensitivity and specificity. The anti-TGt IgA test not only constantly rules out celiac disease, but also functions as a filter for the selection of patients eligible for intestinal biopsy for diagnostic confirmation. The development of serology has enabled the use of new diagnostic strategies that avoid intestinal biopsy, at least in some groups of patients(AU)

Immunoproteomics approach for the discovery of antigens applied to the diagnosis of canine visceral leishmaniasis.

In the present study, an immunoproteomic approach using Leishmania infantum parasites isolated from naturally infected dogs from an endemic region of the disease, was carried out to identify new antigens to be used in the diagnosis of canine visceral leishmaniasis (CVL). Protein extracts, obtained from parasites isolated from asymptomatic (CanLA) and symptomatic (CanLS) dogs, were used to perform the two-dimensional gels. Western Blotting assays were carried out by employing a pool of sera from dogs with visceral leishmaniasis (CanLA or CanLS), healthy dogs from an endemic area, or dogs with similar diseases associated with cross-reactions (babesiosis and ehrlichiosis). With these results, it was possible to exclude the spots that showed a cross-reactivity of the sera from groups of healthy dogs, and those with babesiosis or ehrlichiosis. Taken together, 20 proteins were identified, 15 of which have already been described in the literature and 5 of which are hypothetical. An immunogenomic screen strategy was applied to identify conserved linear B-cell epitopes in the identified hypothetical proteins. Two peptides were synthesized and tested in ELISA experiments as a proof of concept for the validation of our immunoproteomics findings. The results demonstrated that the antigens presented sensitivity and specificity values ranging from 81.93% to 97.59% and 78.14 to 85.12%, respectively. As a comparative antigen, a preparation of a Leishmania extract showed sensitivity and specificity values of 75.90% and 74.88%, respectively. The present study was able to identify proteins capable of being used for the serodiagnosis of canine visceral leishmaniasis.

Reproducibility of double agar gel immunodiffusion test using stored serum and plasma from paracoccidioidomycosis patients

Background: Serological evaluation performed by double agar gel immunodiffusion test (DID) is used for diagnosis, evaluation of severity, management of paracoccidioidomycosis patients, and development of new clinical studies. For these reasons, the Botucatu Medical School of UNESP maintains a serum bank at the Experimental Research Unit with patient clinical data. This study aimed to evaluate the influence of the freeze-thaw cycle and different blood matrices on the titration of circulating antibodies. Methods: The study included 207 patients with confirmed (etiology-demonstrated) or probable (serology-demonstrated) paracoccidioidomycosis, and DID was performed with culture filtrate from Paracoccidioides brasiliensis B339 as antigen. First experiment: the antibody levels were determined in serum samples from 160 patients with the chronic form and 20 with the acute/subacute form, stored at ­80o C for more than six months. Second experiment: titers of 81 samples of serum and plasma with ethylenediaminetetraacetic acid (EDTA) or heparin, from 27 patients, were compared according to matrix and effect of storage at ­20o C for up to six months. Differences of titers higher than one dilution were considered discordant. Results: First experiment: test and retest presented concordant results in serum stored for up to three years, and discordant titers in low incidence in storage for four to six years but high incidence when stored for more than six years, including conversion from reagent test to non-reagent retest. Second experiment: serum, plasma-EDTA and plasma-heparin samples showed concordant titers, presenting direct correlation, with no interference of storage for up to six months. Conclusions: Storage at ­80o C for up to six years has no or little influence on the serum titers determined by DID, permitting its safe use in studies depending on this parameter. The concordant titrations in different blood matrices demonstrated that the plasma can be used for immunodiffusion test in paracoccidioidomycosis, with stability for at least six months after storage at ­20o C.(AU)

Efficacy of some avian influenza H5 vaccines against local highly pathogenic avian influenza viruses subtype H5N8 isolated in 2018 and 2020 in Egypt

Commercial inactivated avian influenza H5 vaccine is used as an essential control strategy for avian influenza disease in Egypt. Since the initial outbreaks of highly pathogenic avian influenza H5N8, the virus has diverged with new genotypes and variant viruses continuing to emerge which mainly stand behind vaccination failure. In the present work, four different commercial avian influenza vaccines were inoculated in specific pathogenic free chickens for assessing its efficacy against local highly pathogenic avian influenza H5N8 virus isolated in 2018 and 2020. Two hundred and forty specific pathogenic free chickens were clustered into four groups; each group was inoculated with the corresponding vaccine (60 specific pathogenic free chickens/vaccine). Sixty specific pathogenic free chicks were kept as control unvaccinated group. Sera collected from vaccinated chicken groups at 3rd and 4th week post vaccination were examined for calculating neutralizing antibodies using heterologous highly pathogenic avian influenza H5N8 2018 and 2020. At 4th week post vaccination, vaccinated chickens were challenged; moreover, oropharyngeal swabs were collected from challenged vaccinated chickens to calculate the viral shedding. Our findings revealed the groups vaccinated with vaccine code no 1 and 2 that contains two vaccine strains (H5N1 and H5N8) of local origin exhibited the highest hemagglutination inhibition titer, protection (percent) and reduction in viral shedding titer when examined by highly pathogenic avian influenza H5N8 2018 while, vaccine code no 3 induced lower antibody response, protection (percent) and reduction in viral shedding, but still within satisfactory level when compared to previous groups. When highly pathogenic avian influenza H5N8 2020 was used, it was found the seroconversion rate, protection (percent) and mean titer of reduction of viral shedding decreased in comparison to those recorded for highly pathogenic avian influenza H5N8 2018. Vaccine code no 4 was impotent to either highly pathogenic avian influenza 2018 or 2020. Accordingly, it was recommended to update vaccine strain according to epidemiological condition and used the predominant circulating strain isolate in challenge test(AU)

La vacuna comercial inactivada H5 se utiliza como estrategia esencial de control de la enfermedad de la gripe aviar en Egipto. Desde los brotes iniciales de la gripe aviar altamente patógena H5N8, el virus ha variado al aparecer continuamente nuevos genotipos y variantes virales, que son los principales responsables del fracaso de la vacunación. En el presente trabajo, cuatro vacunas comerciales diferentes contra la gripe aviar se inocularon en pollos libres de patógenos específicos para evaluar su eficacia contra cepas del virus local de la gripe aviar altamente patógeno H5N8 aisladas en 2018 y 2020. Se agruparon 240 pollos pollos libres de patógenos específicos en cuatro grupos, cada uno fue inoculado con la vacuna correspondiente (60 pollos pollos libres de patógenos específicos/vacuna). Sesenta pollos SPF se mantuvieron como grupo control sin vacunar. Los sueros de los pollos vacunados recogidos en la 3ª y 4ª semana después de la vacunación se examinaron para calcular los anticuerpos neutralizantes contra la gripe aviar heteróloga H5N8 2018 y 2020. En la cuarta semana después de la vacunación, los pollos vacunados fueron retados; además, se recogieron hisopados orofaríngeos de los pollos vacunados retados para calcular la diseminación viral. Nuestros resultados revelaron que los grupos vacunados con las vacunas con códigos nº 1 y 2, que contienen dos cepas vacunales (H5N1 y H5N8) de origen local, mostraron el mayor título de inhibición de la hemaglutinación, protección (por ciento) y reducción del título de excreción viral cuando se evaluaron contra la gripe aviar altamente patógena H5N8 2018, mientras que la vacuna con código nº 3 indujo menor respuesta de anticuerpos, protección (por ciento) y reducción de la excreción viral, pero todavía dentro de un nivel satisfactorio en comparación con los grupos anteriores. Al utilizar la vacuna contra la gripe aviar altamente patógena H5N8 2020, se observó que la tasa de seronconversión, la protección (por ciento) y el título medio de reducción de la excreción viral disminuyeron en comparación con los registrados para la gripe aviar altamente patógena H5N8 2018. La vacuna con código nº 4 no fue potente para la gripe aviar altamente patógena de 2018 o de 2020. Por consiguiente, se recomendó actualizar la cepa de la vacuna de acuerdo con las condiciones epidemiológicas y utilizar el aislamiento de la cepa circulante predominante en la prueba de reto(AU)

Anticuerpos antitransglutaminasa tisular en pacientes con síntomas gastrointestinales / Anti-tissue transglutaminase antibodies in patients with gastrointestinal symptoms

Introducción: La enfermedad celiaca es una enteropatía mediada por la respuesta inmune, que ha sido crecientemente reconocida como una enfermedad común, que afecta tanto a la población infantil, como a la adulta. La serología es un componente clave de la detección y diagnóstico de la celiaquía. Objetivo: Evaluar la utilidad diagnóstica de los anticuerpos antitransglutaminasa tisular en individuos con síntomas gastrointestinales crónicos. Métodos: En un estudio de corte se determinaron los anticuerpos anti-transglutaminasa tisular IgA/G en 87 pacientes adultos y pediátricos con indicación médica de anticuerpos de celiaquía. Los anti- transglutaminasa tisular IgA/G se realizaron por el ensayo inmunoadsorbente ligado a enzima y por el ensayo multiplex de inmunoblot. Se aplicó la prueba U de Mann-Whitney y se calculó el coeficiente de concordancia kappa. Resultados: La seroprevalencia de los anti-transglutaminasa tisular IgG/IgA resultó de 8,05 por ciento (7/87) por el ensayo inmunoenzimático. Los resultados cualitativos del ensayo inmunoenzimático y del inmunoblot para los anti- transglutaminasa tisular fueron concordantes con un coeficiente kappa de 0,407 (p=0,004). La distribución de la concentración de los anticuerpos anti-TGt IgA/G obtenidos por el ensayo inmunoenzimático respecto a los resultados negativos y positivos del inmunoblot no fue significativa (p=0,08). Los pacientes con presencia de anti-transglutaminasa tisular IgA/G por el ensayo inmunoenzimático obtuvieron el diagnóstico definitivo de enfermedad celiaca confirmado por biopsia duodenal. Conclusiones: Se confirmó la utilidad de la detección de los anticuerpos anti-transglutaminasa tisular IgA/G por el ensayo inmunoenzimático como primer paso diagnóstico de la enfermedad celíaca en pacientes con síntomas gastrointestinales(AU)

Introduction: Celiac disease is an immune-mediated enteropathy that has been increasingly recognized as a common disease, affecting both the pediatric and adult population. Serology is a key component of the detection and diagnosis of celiac disease. Objective: To evaluate the diagnostic usefulness of anti-tissue transglutaminase antibodies in individuals with chronic gastrointestinal symptoms. Methods: In a cutoff study, anti-tissue transglutaminase IgA/G antibodies were determined in 87 adult and pediatric patients with medical indication for celiac disease antibodies. Anti-tissue transglutaminase IgA/G was performed by enzyme-linked immunoadsorbent assay and multiplex immunoblot assay. Mann-Whitney U test was applied and kappa correspondence coefficient was calculated. Results: The seroprevalence of anti-tissue transglutaminase IgG/IgA was 8.05 percent (7/87) by enzyme-linked immunosorbent assay. The qualitative results of the enzyme-linked immunosorbent assay and immunoblot for anti-tissue transglutaminase were consistent with a kappa coefficient of 0.407 (p=0.004). The distribution of the concentration of anti-TGt IgA/G antibodies obtained by enzyme-linked immunosorbent assay with respect to negative and positive immunoblot results was not significant (p=0.08). Patients with presence of anti-tissue transglutaminase IgA/G by enzyme-linked immunosorbent assay obtained the definitive diagnosis of celiac disease confirmed by duodenal biopsy. Conclusions: The usefulness of detection of anti-tissue transglutaminase IgA/G antibodies by enzyme-linked immunosorbent assay as a first diagnostic step of celiac disease in patients with gastrointestinal symptoms was confirmed(AU)

Simulation of group testing scenarios can boost COVID-19 screening power.

The COVID-19 has severely affected economies and health systems around the world. Mass testing could work as a powerful alternative to restrain disease dissemination, but the shortage of reagents is a limiting factor. A solution to optimize test usage relies on 'grouping' or 'pooling' strategies, which combine a set of individuals in a single reaction. To compare different group testing configurations, we developed the poolingr package, which performs an innovative hybrid in silico/in vitro approach to search for optimal testing configurations. We used 6759 viral load values, observed in 2389 positive individuals, to simulate a wide range of scenarios. We found that larger groups (>100) framed into multi-stage setups (up to six stages) could largely boost the power to detect spreaders. Although the boost was dependent on the disease prevalence, our method could point to cheaper grouping schemes to better mitigate COVID-19 dissemination through identification and quarantine recommendation for positive individuals.

Leishmania exposure in dogs from two endemic countries from New and Old Worlds (Brazil and Portugal): evaluation of three serological tests using Bayesian Latent Class Models.

BACKGROUND: Zoonotic leishmaniosis caused by Leishmania infantum is endemic in several countries of the Mediterranean Basin, Latin America, and Asia. Dogs are the main hosts and reservoirs of human infection. Thus, from a One Health perspective, early diagnosis of Leishmania infection in dogs is essential to control the dissemination of the parasite among other dogs and to humans. The aim of this study was to estimate the diagnosis accuracy of three serological tests to detect antibodies to Leishmania in dogs from two endemic settings using Bayesian latent class models (BLCM). METHODS: A total of 378 dogs from two Portuguese and Brazilian endemic areas of leishmaniosis (194 animals from Portugal and 184 from Brazil) were screened. Detection of anti-Leishmania antibodies was performed using two commercial ELISA (L. infantum IgG-ELISA® and EIE-LVC®) and a rapid immunochromatographic test (DPP-LVC®). Bayesian latent class models were used to estimate Leishmania infection prevalence, together with sensitivities and specificities of the three diagnostic tests, in the two dog populations simultaneously. Predictive values were also calculated. Credibility intervals (CI) were obtained, considering different types of prior information. RESULTS: A posterior median Leishmania seroprevalence of 13.4% (95% CI 9.0-18.7) and of 21.6% (15.0-28.3) was estimated to the Portuguese and Brazilian dog subpopulations, respectively. The Bayesian analysis indicated that all tests were highly specific (specificity above 90%), and that the DPP-LVC® was more sensitive (96.6%; 83.1-99.9) than both ELISAs in the Portuguese subpopulation, while in the Brazilian subpopulation, EIE-LVC® and L. infantum IgG-ELISA®, had the highest sensitivity (88.2%; 73.7-97.0) and specificity (98.7%; 95.1-99.9), respectively. CONCLUSIONS: In general, the levels of diagnosis accuracy of the three serological tests to detect Leishmania antibodies assessed by BLCM indicate their utility in canine epidemiological studies. The same approach should be used to assess the performance of these techniques in the clinical management of infected and sick dogs using representative samples from the wide spectrum of clinical situations, namely from subclinical infection to manifest disease. The low positive predictive value of the serological tests used in the current protocol of the Brazilian Ministry of Health suggests that they should not be used individually and may not be sufficient to target reservoir-based control interventions.