Antonio Walter Ferreira

Pattern of humoral immune response to Plasmodium falciparum blood stages in individuals presenting different clinical expressions of malaria

BackgroundThe development of protective immunity against malaria is slow and to be maintained, it requires exposure to multiple antigenic variants of malaria parasites and age-associated maturation of the immune system. Evidence that the protective immunity is associated with different classes and subclasses of antibodies reveals the importance of considering the quality of the response. In this study, we have evaluated the humoral immune response against Plasmodium falciparum blood stages of individuals naturally exposed to malaria who live in endemic areas of Brazil in order to assess the prevalence of different specific isotypes and their association with different malaria clinical expressions.MethodsDifferent isotypes against P. falciparum blood stages, IgG, IgG1, IgG2, IgG3, IgG4, IgM, IgE and IgA, were determined by ELISA. The results were based on the analysis of different clinical expressions of malaria (complicated, uncomplicated and asymptomatic) and factors related to prior malaria exposure such as age and the number of previous clinical malaria attacks. The occurrence of the H131 polymorphism of the FcγIIA receptor was also investigated in part of the studied population.ResultsThe highest levels of IgG, IgG1, IgG2 and IgG3 antibodies were observed in individuals with asymptomatic and uncomplicated malaria, while highest levels of IgG4, IgE and IgM antibodies were predominant among individuals with complicated malaria. Individuals reporting more than five previous clinical malaria attacks presented a predominance of IgG1, IgG2 and IgG3 antibodies, while IgM, IgA and IgE antibodies predominated among individuals reporting five or less previous clinical malaria attacks. Among individuals with uncomplicated and asymptomatic malaria, there was a predominance of high-avidity IgG, IgG1, IgG2 antibodies and low-avidity IgG3 antibodies. The H131 polymorphism was found in 44.4% of the individuals, and the highest IgG2 levels were observed among asymptomatic individuals with this allele, suggesting the protective role of IgG2 in this population.ConclusionTogether, the results suggest a differential regulation in the anti-P. falciparum antibody pattern in different clinical expressions of malaria and showed that even in unstable transmission areas, protective immunity against malaria can be observed, when the appropriated antibodies are produced.

II Consenso Brasileiro em Doença de Chagas, 2015

Chagas disease is a neglected chronic condition that presents high morbidity and mortality burden, with considerable psychological, social, and economic impact. The disease represents a significant public health issue in Brazil, with different regional patterns. This document presents the evidence that resulted in the Brazilian Consensus on Chagas Disease. The objective was to review and standardize strategies for diagnosis, treatment, prevention, and control of Chagas disease in the country, based on the available scientific evidence. The consensus is based on collaboration and contribution of renowned Brazilian experts with vast knowledge and experience on various aspects of the disease. It is the result of close collaboration between the Brazilian Society of Tropical Medicine and the Ministry of Health. This document shall strengthen the development of integrated control measures against Chagas disease in the country, focusing on epidemiology, management, comprehensive care (including families and communities), communication, information, education, and research.

Cross sectional study reveals a high percentage of asymptomatic Plasmodium vivax infection in the Amazon Rio Negro area, Brazil

A parasitological, clinical, serological and molecular cross-sectional study carried out in a highly endemic malaria area of Rio Negro in the Amazon State, Brazil, revealed a high prevalence of asymptomatic Plasmodium vivax infection. A total of 109 persons from 25 families were studied in five villages. Ninety-nine inhabitants (90.8%) had at least one previous episode of malaria. Serology showed 85.7% and 46.9% of positivity when P. falciparum antigens and P. vivax MSP-1, respectively, were used. Twenty blood samples were PCR positive for P. vivax (20.4%) and no P. falciparum infection was evidenced by this technique. No individual presenting positive PCR reaction had clinical malaria during the survey neither in the six months before nor after, confirming that they were cases of asymptomatic infection. Only one 12 year old girl presented a positive thick blood smear for P. vivax. This is the first description of asymptomatic Plasmodium infection in this area studied.

2 nd Brazilian Consensus on Chagas Disease, 2015

Chagas disease is a neglected chronic condition with a high burden of morbidity and mortality. It has considerable psychological, social, and economic impacts. The disease represents a significant public health issue in Brazil, with different regional patterns. This document presents the evidence that resulted in the Brazilian Consensus on Chagas Disease. The objective was to review and standardize strategies for diagnosis, treatment, prevention, and control of Chagas disease in the country, based on the available scientific evidence. The consensus is based on the articulation and strategic contribution of renowned Brazilian experts with knowledge and experience on various aspects of the disease. It is the result of a close collaboration between the Brazilian Society of Tropical Medicine and the Ministry of Health. It is hoped that this document will strengthen the development of integrated actions against Chagas disease in the country, focusing on epidemiology, management, comprehensive care (including families and communities), communication, information, education, and research .

Malária humana: padronização e optimização de testes sorológicos para diagnóstico individual e inquéritos soroepidemiológicos

The indirect immunofluorescence antibody test (IFA) is normally employed as reference test in the serology of malaria. In this report we standardized and optimized the test, for our condition, utilizing P. falciparum obtained from human blood on culture and P. vivax obtained from human blood as antigens, for detection of IgG and IgM antibodies. Some technical variables, were tested and best resulto were obtained when sera were diluted in PBS containing 1% Tween-80 and the slides, containing the antigenic preparation were fixed in cold acetone or stabilized on dried air with silica. The ELISA test was standardized for P. falciparum antibodies and the comparison of the IFA and ELISA showed: a) in P. falciparum prime infected patient the sensitivity was 71% for both tests; b) in P. vivax prime infected patients the sensitivity was 40% for both tests; c) in non prime infected patients with P. falciparum malaria the sensitivity was 100% for both tests; d) in non prime infected patients with P. vivax malaria the sensitivity was 85% for ELISA and 92% for IFA; e) in patients with P. vivax and P. falciparum malaria the sensitivity was 100% for both tests. The specificity was 95% for ELISA and 100% for IFA in non malaria individuals. The results showed that the ELISA test could be an alternative for IFA for IgG antibodies in the serology of malaria.O teste de imunofluorescencia indireta (IFI) e considerado teste de referencia na soroiogia da malaria. Neste trabalho procuramos optimizar o teste empregando P. falciparum obtido de sangue humano e de cultura e P. vivax obtido de sangue de paciente como antigenos, para pesquisa de anticorpos IgG e IgM. Das variaveis tecnicas estudadas melhores resultados foram obtidos quando os soros foram diluidos ern PBS contendo 1% de Tween 80 e as lâminas contendo a suspensao antigenica foram estabilizadas em dessecadores ou fixadas com acetona. Foi tambem padronizado o teste imunoenzimatico ELISA com antigenos de P. falciparum obtidos em cultura. O estudo comparativo com o teste de imunofluorescencia indireta para pesquisa de anticorpos IgG mostrou: a) nos pacientes primo infectados por P. falciparum a sensibilidade para ambos os testes foi de 71%; b) nos pacientes primo infectados pelo P. vivax a sensibilidade foi de 40% para ambos os testes; c) nos pacientes nao primo infectados e com malaria atual pelo P. falciparum a sensibilidade para ambos os testes foi de 100%; d) nos pacientes nao primo infectados e com malaria atual pelo P. vivax a sensibilidade foi de 85% para o teste ELISA e de 92% para a IFI; e) nos pacientes com malaria mista a sensibilidade para ambos os testes foi de 100%. A especificidade da IFI foi de 100% e do teste ELISA 95% nos casos de individuos nao malaricos. Os resultados obtidos sugerem ser o teste ELISA, uma boa alternativa para o teste de IFI, para a pesquisa de anticorpos IgG anti P. falciparum, na soroiogia da malaria.

Enhancement of Diagnostic Efficiency by a Gamma Interferon Release Assay for Pulmonary Tuberculosis

ABSTRACT This study was designed to examine the use of the QuantiFERON-TB Gold assay as an aid in the diagnosis of active pulmonary tuberculosis (TB) in Brazilian patients. Using the receiver operating characteristic curve, the cutoff was adjusted to ≥0.20 IU/ml. The sensitivity increased to 86%, with 100% specificity. All TB patients with negative sputum smear microscopy and negative culture results were positive using this test.

Freqüência de indivíduos com anticorpos sericos anti-Cysticercus cellulosae em cinco Municípios do Estado de São Paulo

Considering the important health public problem that human cysticercosis represents, the frequency of anti-Cysticercus cellulosae antibodies was studied in 1,264 serum samples, 1,064 being from the general population individuals (821 adults and 243 children) living in five municipalities of Sao Paulo State, Brazil; and 200 from patients admitted to the Psychiatric Hospital Bezerra de Menezes (Presidente Prudente). Discs of synthetic fabric-resin with the Among the sera from adults, nineteen (2,30%) were valently bound were employed for ELISA tests. Among the sera from adults, mineteen (2.30%) were reactive 2 (0.82%) among the childrens sera. Ten (5.00%) among the psychiatric patients sera presented reactivity. This was significantly higher than that observed for the adults of the general population group (p < 0.05).Considering the important health public problem that human cysticercosis represents, the frequency of anti-Cysticercus cellulosae antibodies was studied in 1,264 serum samples, 1,064 being from the general population individuals (821 adults and 243 children) living in five municipalities of São Paulo State, Brazil; and 200 from patients admitted to the Psychiatric Hospital Bezerra de Menezes (Presidente Prudente). Discs of synthetic fabric-resin with the valently bound were employed for ELISA tests. Among the sera from adults, nineteen (2.30%) were reactive 2 (0.82%) among the children sera. Ten (5.00%) among the psychiatric patients sera presented reactivity. This was significantly higher than that observed for the adults of the general population group (p less than 0.05).

Imunodiagnóstico da neurocisticercose: teste imunoenzimático com antígenos quimicamente ligados a suportes para pesquisa de anticorpos em soro e líquido cefalorraquiano

Foi padronizado o teste imunoenzimatico, ELISA, utilizando-se componentes antigenicos de Cysticercus cellulosae quimicamente ligados a suportes solidos constituidos de discos de tecido-resina (ELISA-d), para pesquisa de anticorpos em soro liquido cefalorraquiano (LCR), ensaiando-se uma unica diluicao do especime clinico. O suporte tecido-resina foi composto de tecido de poliester impregnado com resina polimerizada de N-metilol-acrilamida, apresentando grupos N-metilol livres, capazes de reagir covalentemente com grupos funcionais de proteinas e polissacarideos presentes no extrato antigenico salino total obtido de cisticercos. Foram ensaiados 38 soros e 74 LCR de pacientes com neurocisticercose comprovada e 50 soros e 107 LCR do grupo controle (pacientes com quadros clinicos neurologicos diversos e individuos supostamente normais). Obtivemos os seguintes indices de sensibilidade e especificidade: 94,7% e 92,0% para o teste realizado no soro e 98,6% e 100% para o teste realizado no LCR. O teste ELISA-d mostrou-se eficiente para o diagnostico da neurocisticercose, principalmente quando realizado no LCR, com vantagens de estabilidade, facilidade de execucao e baixo custo.The enzyme-linked immunosorbent assay, ELISA, was developed in a new type of support consisting of discs of sinthetic fabric-resin (ELISA-d) with antigenic components of Cysticercus cellulosae covalently bound for detection of antibodies in sera and cerebrospinal fluid (CSF). The support fabric-resin consistis of poliester fabric coated with crosslinked resin (N-methylol-acrylamide) containing N-methylol groups able to form covalent bounds with functional groups of proteins and polysaccharides which are present in the antigenic saline extract obtained from Cysticercus cellulosae. Sera titer and CSF titer were determined using only one dilution according to the dose-response standard curves obtained. Thirty-eight sera and 74 CSF from patients with confirmed diagnosis of neurocysticercosis and 50 sera and 107 CSF from a control group (patients suffering from neurological disorders other than neurocysticercosis and supposedly healthy individuals) were assayed The sensitivity and the specificity of ELISA-d were determined: 94.7% and 92.0% for sera and 98.6% and 100% for CSF. The ELISA-d test proved to be efficient for the diagnosis of neurocysticercosis, mainly when carried out in CSF, with the advantages of good stability, easy preparation and execution and low cost.

Observações sobre o TESA blot no diagnóstico sorológico da doença de Chagas

TESA blot was compared with indirect hemagglutination, indirect immunofluorescence and ELISA tests. In sera from 30 participants infected with Trypanosoma cruzi, and in 30 non infected the four techniques produced entirely equivalent results, all positive and all negative, respectively. In cases admitted to be inconclusive or in visceral leishmaniasis, frequent false positives were detected. However, TESA blot contributed with the least proportion of them.

High diagnostic efficiency of IgM-ELISA with the use of multiple antigen peptides (MAP1) from T. gondii ESA (SAG-1, GRA-1 and GRA-7), in acute toxoplasmosis.

The main serological marker for the diagnosis of recent toxoplasmosis is the specific IgM antibody, along with IgG antibodies of low avidity. However, in some patients these antibodies may persist long after the acute/recent phase, contributing to misdiagnosis in suspected cases of toxoplasmosis. In the present study, the diagnostic efficiency of ELISA was evaluated, with the use of peptides derived from T. gondii ESA antigens, named SAG-1, GRA-1 and GRA-7. In the assay referred to, we studied each of these peptides individually, as well as in four different combinations, as Multiple Antigen Peptides (MAP), aiming to establish a reliable profile for the acute/recent toxoplasmosis with only one patient serum sample. The diagnostic performance of the assay using MAP1, with the combination of SAG-1, GRA-1 and GRA-7 peptides, demonstrated better discrimination of the acute/recent phase from non acute/recent phase of toxoplasmosis. Our results show that IgM antibodies to MAP1 may be useful as a serological marker, enhancing the diagnostic efficiency of the assay for acute/recent phase of toxoplasmosis.