Perfil antigénico en fase aguda y crónica de toxoplasmosis en embarazadas por la técnica de Western Blot / Antigenic profile in the acute and chronic phase of toxoplasmosis in pregnant women using the Western Blot technique

La toxoplasmosis es una enfermedad endémica con prevalencia mundial variable, cuyo agente causal es el parásito Toxoplasma gondii. Para un diagnóstico certero de la infección por T. gondii son necesarias combinaciones de métodos serológicos. Estudios recientes han reportado que la técnica de Western Blot permite evidenciar proteínas antigénicas como marcadores de la infección, así como ciertos perfiles proteicos como posibles indicadores de las fases de la infección, aguda y crónica. El objetivo del estudio fue identificar el perfil antigénico específico asociado a las diferentes fases de la toxoplasmosis. Fueron incluidos en el estudio 55 sueros de embarazadas con toxoplasmosis, diferenciados en fase aguda y crónica de la enfermedad por medio del método de ELISA de Avidez de IgG. Mediante el método de Western Blot se observó que las proteínas antigénicas p35, p43, p45, p56 y p107 fueron reconocidas por el 20- 60% de los sueros de pacientes en fase aguda, mientras que p65, p95, p98 y p113 fueron reconocidas por el 17-35% de sueros de pacientes en fase crónica. Se observó que seis proteínas antigénicas, p32, p38, p41, p48, p59 y p72, fueron reconocidas por más del 60% de los sueros de pacientes tanto en fase aguda como crónica. Los resultados obtenidos sugieren que estas seis proteínas podrían ser consideradas como marcadores diagnósticos de la enfermedad(AU)

Toxoplasmosis is an endemic disease with variable global prevalence, being the causative agent the parasite Toxoplasma gondii. For an accurate diagnosis of a T. gondii infection, combinations of serological methods are required. Recent studies have reported that the Western Blot technique allows the detection of antigenic proteins as markers of infection, as well as certain protein profiles as possible indicators of acute and chronic phases of infection. The objective of the study was to identify the specific antigenic profile associated with different phases of toxoplasmosis. Fifty five sera from pregnant women with toxoplasmosis were included in the study, differentiated in acute and chronic phase of the disease by an IgG Avidity ELISA. By using the Western Blot method it was observed that antigenic proteins p35, p43, p45, p56 and p107 were recognized by 20-60% of sera from patients in acute phase, while p65, p95, p98 and p113 were recognized by 17-35% of sera from patients in chronic phase. It was observed that six antigenic proteins, p32, p38, p41, p48, p59 and p72, were recognized by more than 60% of sera from patients in both acute and chronic phases. The results obtained in this study suggest that these six proteins could be considered as diagnostic markers of the disease(AU)

Performance of a rapid diagnostic test for the detection of visceral leishmaniasis in a large urban setting

Introduction Rapid diagnostic tests (RDTs) may improve the early detection of visceral leishmaniasis (VL), but their real-world performance requires additional study. Therefore, we evaluated the performance of an rK39-based RDT (Kalazar Detect™) for the detection of VL in an endemic, large urban area. Methods Data were collected from a registry of rK39 RDT performed at 11 emergency care units in Belo Horizonte, Brazil, and from a national database of reportable communicable diseases of the Sistema de Informação de Agravos de Notificação (SINAN). Results The rapid rK39 test was performed in 476 patients, with 114 (23.9%) positive results. The analysis of rK39 RDT performance was based on 381 (80%) cases reported to the SINAN database, of which 145 (38.1%) were confirmed cases. Estimates for sensitivity and specificity were 72.4% (95% CI: 64.6-79%) and 99.6% (95%CI: 97.6-99.9%), respectively. Positive and negative predictive values were estimated at 99.1% (95%CI: 94.9-99.8%) and 85.5% (95%CI: 80.8-89.1%), respectively. In addition, close agreement between the rK39 RDT and indirect immunofluorescence was observed. Conclusions In summary, the rK39 RDT showed a high specificity but only moderate sensitivity. In endemic areas for VL, treatment may be considered in cases with clinical manifestations and a positive rK39 RDT, but those with a negative test should be subjected to further investigation. .

IgG AVIDITY WESTERN BLOT USING Toxoplasma gondii rGRA-7 CLONED FROM NUCLEOTIDES 39-711 FOR SERODIAGNOSIS OF ACUTE TOXOPLASMOSIS / Avidez do IgG pelo Western Blot usando o r GRA-7 do Toxoplasma gondii clonado de nucleotídeos 39-711 para sorodiagnóstico de toxoplasmose aguda

Toxoplasmosis is an important cause of congenital infection. The present study was performed to evaluate the usefulness of recombinant (r) GRA-7 cloned from nucleotides (n) 39-711 in discriminating between acute and chronic toxoplasmosis. First, commercial IgM, IgG and IgG avidity ELISAs were used to determine the serological profile of the sera. Serum samples were from 20 symptomatic patients with acute infection (low IgG avidity, IgM positive), 10 with chronic infection (high IgG avidity, IgM negative) and 10 with indeterminate IgG avidity (IgM positive) which were tested for IgG avidity status with an in-house developed IgG avidity Western blot using the rGRA-7 recombinant antigen. All 20 sera from cases of probable acute infection showed bands which either faded out completely or reduced significantly in intensity after treatment with 8 M urea, whereas the band intensities of the 10 serum samples from chronic cases remained the same. Of the 10 sera with indeterminate IgG avidity status, after treatment with 8 M urea the band intensities with six sera remained the same, two sera had completely faded bands and another two sera had significantly reduced band intensities. Discrimination between acute and chronic toxoplasmosis was successfully performed by the in-house IgG avidity Western blot.

Toxoplasmose é uma causa importante de infecção congênita. O presente estudo foi feito para avaliar o uso do recombinante (r) GRA-7 clonado de nucleotídeos (n) 30-711 para discriminar entre toxoplasmose aguda e crônica. Inicialmente IgM, IgG e ELISA avidez IgG comerciais foram usados para determinar o perfil sorológico do soro. Amostras de soro de 20 pacientes sintomáticos com infecção aguda (IgG avidez baixa, IgM positivo), 10 com infecção crônica (alta avidez IgG, IgM negativo) e 10 com avidez IgG indeterminada (IgM positivo) que foram testados para o status de avidez IgG com um doméstico Western Blot desenvolvendo avidez IgG usando o rGRA-7 antígeno recombinante. Todos os 20 soros de provável infecção aguda mostraram bandas que ou se apagaram completamente ou tiveram a sua intensidade significantemente reduzida após tratamento com uréia 8 M, enquanto as intensidades das bandas das 10 amostras de soros de casos crônicos permaneceram iguais. Dos 10 soros com status indeterminado de avidez de IgG, após tratamento com uréia 8 M a intensidade das bandas em seis soros permaneceram iguais, dois soros tiveram bandas apagadas completamente e dois outros tiveram significante redução da intensidade das bandas. Discriminação entre toxoplasmose aguda e crônica foi feita com sucesso através do IgG avidez Western blot doméstico.

Prevalência de infecção por Leishmania chagasi utilizando os métodos de ELISA ( rK39 e CRUDE ) e intradermorreação de Montenegro em área endêmica do Maranhão, Brasil / Prevalence of infection by Leishmania chagasi using ELISA ( rK39 and CRUDE ) and the Montenegro skin test in an endemic leishmaniasis area of Maranhão, Brazil

Realizou-se estudo prospectivo com 1.520 indivíduos menores de 15 anos no Município de São José de Ribamar, Maranhão, Brasil, de junho de 1994 a janeiro de 1995, com o objetivo de avaliar a prevalência e as características (fatores sócio-econômicos, ambientais e hábitos de vida) associadas à infecção por Leishmania chagasi. Realizou-se Intradermorreação de Montenegro (IDRM) e sorologia por Enzyme Linked Immunosorbant Assay (ELISA-rK39 e CRUDE). Na análise estatística foi utilizado o teste chi2 com correção de Yates, sendo considerado significante um valor de p < 0,05. A prevalência de infecção foi de 61,7 por cento pela IDRM, 19,4 por cento pelo ELISA-rK39 e 19,7 por cento pelo ELISA-CRUDE. Foi observada associação entre leishmaniose na família (p = 0,001), tipo de abastecimento de água (p = 0,000) e aplicação de inseticida (p = 0,000) com a infecção por L. chagasi pela IDRM. Nenhuma associação com infecção por L. chagasi foi observada utilizando-se a sorologia ELISA-rK39 ou CRUDE. Medidas de controle mais efetivas são necessárias para reduzir a prevalência da doença e detectar casos assintomáticos dentre o elevado porcentual de infectados nessa localidade.

The chronic presence of the parasite, and anti-P autoimmunity in Chagas disease: the Trypanosoma cruzi ribosomal P proteins, and their recognition by the host immune system

Molecular expression cloning techniques revealed that patients with the severest clinical form of Chagas disease, chronic Chagas heart disease, presented a strong humoral response against the cloned C-terminal portion of a Trypanosoma cruzi ribosomal P protein. Parasite P antigens identification led to characterize the ribosomal P protein system in T. cruzi. Their exposed location on the ribosome, and the ®amplification® of their parasite specific, serine free C-terminal domain, generate a strong parasite specific anti-P response, that in certain cases may induce anti-P autoimmunity