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Resumen La determinación de anticuerpos anti-dsDNA es de utilidad para el diagnóstico y seguimiento clínico de pacientes con lupus eritematoso sistémico (LES) y es uno de los criterios de clasificación del SLICC-2012. El objetivo del estudio fue verificar el desempeño del inmunoensayo quimioluminiscente (CLIA) QUANTA Flash dsDNA y compararlo con el método en uso de inmunofluorescencia indirecta en Crithidia luciliae (CLIFT). Se analizaron con ambos métodos 195 pacientes con diagnóstico de enfermedades del tejido conectivo y solicitud de anticuerpos anti-dsDNA. Se obtuvieron 38 sueros positivos, 133 negativos y 24 (12,3%) discordantes. Entre estos resultados discordantes, hubo 17 que correspondieron a pacientes con LES y se agruparon en 16 CLIA+/CLIFT- y 1 CLIA-/CLIFT+. Se verificó el desempeño para precisión siguiendo el protocolo EP15-A2 y la linealidad. Se estudió la concordancia mediante el coeficiente Kappa y la correlación con el coeficiente Rho de Spearman. Se observó mayor sensibilidad diagnóstica para CLIA. El grado de acuerdo fue moderado y se obtuvo buena correlación entre los valores cuantitativos de CLIA y los títulos de CLIFT. De acuerdo al buen desempeño encontrado y a los resultados discordantes analizados, la mejor estrategia para la implementación de CLIA sería utilizarla en combinación con CLIFT, lo que aumentaría la sensibilidad diagnóstica sin perder especificidad.
Abstract The detection of anti-dsDNA antibodies is useful for diagnosis and clinical monitoring of patients with systemic lupus erythematosus (SLE) and it is part of the classification criteria according to SLICC 2012. The purpose of this study was to verify the performance of the chemiluminescent immunoassay (CLIA) QUANTA Flash dsDNA and to compare it with the method currently in use, i.e the indirect immunofluorescence in Crithidia luciliae (CLIFT). One hundred and ninety five patients, who presented connective tissue diseases and required the study of anti-dsDNA antibodies, were analyzed. Thirty eight positive serum samples were obtained, 133 were negative and 24 (12.3%) in disagreement. Within the discordant results, there were 17 that corresponded to patients with SLE and they were grouped in 16 CLIA+/CLIFT- and 1 CLIA-/CLIFT+. The accuracy performance was assessed according to the EP15-A2 protocol and linearity. Concordance and correlation were calculated with the Kappa and Spearman's Rho coefficient, respectively. Based on the good performance observed and the discordant results analyzed, the best strategy for CLIA implementation would be to combine it with CLIFT, which would increase the diagnostic sensitivity without losing specificity.
Resumo A determinação dos anticorpos anti-dsDNA é de utilidade para o diagnóstico e seguimento clinico de pacientes com lúpus eritematoso sistêmico (LES) e é um dos critérios de classificação do SLICC 2012. O objetivo do estudo foi verificar o desempenho do imunoensaio quimioluminescente (CLIA) QUANTA Flash dsDNA e compará-lo com o método em uso imunofluorescência indireta em Crithidia luciliae (CLIFT). Foram analisados com os dois métodos, 195 pacientes com diagnóstico de doenças do tecido conjuntivo e solicitude de anticorpos anti-dsDNA. Os resultados foram agrupados em 38 soros positivos, 133 negativos e 24 (12,3%) discordantes. Entre esses resultados discordantes, 17 corresponderam a pacientes com LES e se agruparam em 16 CLIA+/CLIFT- e 1 CLIA-/CLIFT+. Foi verificado o desempenho para precisão seguindo o protocolo EP15-A2 e a linearidade. Foi estudada a concordância mediante o coeficiente Kappa e correlação com o coeficiente Rho de Spearman. Observou-se maior sensibilidade diagnóstica para CLIA. O grau de acordo foi moderado e boa correlação foi observada entre os valores quantitativos de CLIA e os títulos de CLIFT. Com base no bom desempenho encontrado e nos resultados discordantes analisados, a melhor estratégia para implementar o CLIA seria utilizá-lo em combinação com o CLIFT, o que aumentaria a sensibilidade do diagnóstico sem perder a especificidade.
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Glycoalkaloids are important secondary metabolites accumulated by plants as protection against pathogens. One of them, α-tomatine, is found in high concentrations in green tomato fruits, while in the ripe fruits, its aglycone form, tomatidine, does not present a protective effect, and it is usual to find parasites of tomatoes like Phytomonas serpens in these ripe fruits. To investigate the sensitivity of trypanosomatids to the action of α-tomatine, we used logarithmic growth phase culture of 20 trypanosomatids from insects and plants and Trypanosoma cruzi. The lethal dose 50% (LD50) was determined by mixing 107 cells of the different isolates with α-tomatine at concentrations ranging from 10-3 to 10-8 M for 30 min at room temperature. The same tests performed with the tomatidine as a control showed no detectable toxicity against the same trypanosomatid cultures. The tests involved determination of the percentage (%) survival of the protozoan cultures in a Neubauer chamber using optical microscopy. The LD50 values varied from 10-4 to 10-6 M α-tomatine. Slight differences were detected among the LD50 values of the analyzed samples, and none of them showed evidence of resistance to the action of tomatinase, as shown by some pathogenic fungi.
Os glicoalcaloides são metabólitos secundários importantes produzidos pelas plantas e estão envolvidos em sua proteção contra agentes patogênicos. Um deles, α-tomatina, é encontrado em altas concentrações em frutos de tomate verde, enquanto que, nos frutos maduros, sua forma aglicona, tomatidina, não apresenta um efeito protetor, sendo comum encontrar parasitas de tomates como Phytomonas serpens nesses frutos maduros. Para investigar a sensibilidade dos tripanossomatídeos à ação da α-tomatina, utilizamos formas de cultura em fase logarítmica de 20 tripanossomatídeos de plantas e insetos e Trypanosoma cruzi. A dose letal 50% (DL50) foi determinada, misturando 107 células das formas de cultura com concentrações de 10-3 a 10-8 M de α-tomatina durante trinta minutos a temperatura ambiente. Testes realizados com a tomatidina como controle não mostraram toxicidade detectável contra os mesmos tripanossomatídeos. Os testes foram avaliados pela porcentagem (%) de sobrevivência das formas de cultura dos protozoários observados por microscopia óptica em câmara de Neubauer. Os resultados da determinação de DL50 mostraram que esta variou entre 10-4 a 10-6 M de α-tomatina. Pequenas diferenças foram observadas entre os valores de DL50 das amostras analisadas, e nenhuma delas mostrou evidência de resistência pela ação da tomatinidase, como demonstrado em alguns fungos patogênicos.
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Solanum lycopersicum/parasitología , Solanum lycopersicum/toxicidad , Tomatina/análisis , Trypanosoma cruzi/parasitologíaRESUMEN
Objective:To explore the co-detection of natural infection of Trypanosomatidae parasites such as Leishmania and Crithidia in reservoir hosts of leishmaniasis. Methods: Rodent populations were monitored in two endemic foci of cutaneous leishmaniasis of Fars province, southern Iran from March to October 2016. Rodents were trapped alive in several parts of Shiraz and Kharameh cities. Afterwards, their organs were prepared for detection of Leishmania and Crithidia species by molecular, microscopic, and culture methods. Results: Totally, 115 rodents of five species; Tatera indica (T. indica) (85), Rattus rattus (12), Meriones libycus (9), Mus musculus (7), and Rattus norvegicus (2), were trapped alive and their tissue samples were examined using microscopic, cultivation, and molecular assays. Overall, 59 (51.3％) rodents were positive for Leishmania or Crithidia parasites. The highest rate (61.2％; 52/85) of Leishmania infection was related to the T. indica population. The cultivation, and molecular observations showed that two (2.4％; 2/85) of T. indica (foot-pad, and spleen samples) were positive to Crithidia. Conclusions: This is the first report of Crithidia infection in T. indica in Iran. Consequently, more epidemiological and ecological studies are needed to understand the role of Crithidia and Leishmania in T. indica.
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Objective: To explore the co-detection of natural infection of Trypanosomatidae parasites such as Leishmania and Crithidia in reservoir hosts of leishmaniasis. Methods: Rodent populations were monitored in two endemic foci of cutaneous leishmaniasis of Fars province, southern Iran from March to October 2016. Rodents were trapped alive in several parts of Shiraz and Kharameh cities. Afterwards, their organs were prepared for detection of Leishmania and Crithidia species by molecular, microscopic, and culture methods. Results: Totally, 115 rodents of five species; Tatera indica (T. indica) (85), Rattus rattus (12), Meriones libycus (9), Mus musculus (7), and Rattus norvegicus (2), were trapped alive and their tissue samples were examined using microscopic, cultivation, and molecular assays. Overall, 59 (51.3%) rodents were positive for Leishmania or Crithidia parasites. The highest rate (61.2%; 52/85) of Leishmania infection was related to the T. indica population. The cultivation, and molecular observations showed that two (2.4%; 2/85) of T. indica (foot-pad, and spleen samples) were positive to Crithidia. Conclusions: This is the first report of Crithidia infection in T. indica in Iran. Consequently, more epidemiological and ecological studies are needed to understand the role of Crithidia and Leishmania in T. indica.
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BACKGROUND Knowledge on synanthropic phlebotomines and their natural infection by Leishmania is necessary for the identification of potential areas for leishmaniasis occurrence. OBJECTIVE To analyse the occurrence of Phlebotominae in gallery forests and household units (HUs) in the city of Palmas and to determine the rate of natural infection by trypanosomatids. METHODS Gallery forests and adjacent household areas were sampled on July (dry season) and November (rainy season) in 2014. The total sampling effort was 960 HP light traps and eight Shannon traps. Trypanosomatids were detected in Phlebotominae females through the amplification of the SSU rDNA region, and the positive samples were used in ITS1-PCR. Trypanosomatid species were identified using sequencing. FINDINGS A total of 1,527 sand flies representing 30 species were captured in which 949 (28 spp.) and 578 (22 spp.) were registered in July and November, respectively. In July, more specimens were captured in the gallery forests than in the HUs, and Nyssomyia whitmani was particularly frequent. In November, most of the specimens were found in the HUs, and again, Ny. whitmani was the predominant species. Lutzomyia longipalpis was commonly found in domestic areas, while Bichromomyia flaviscutellata was most frequent in gallery forests. Molecular analysis of 154 pools of females (752 specimens) identified Leishmania amazonensis, L. infantum, and Crithidia fasciculata in Ny. whitmani, as well as L. amazonensis in Lu. longipalpis, Trypanosoma sp. and L. amazonensis in Pintomyia christenseni, and L. amazonensis in both Psathyromyia hermanlenti and Evandromyia walkeri. MAIN CONCLUSIONS These results show the importance of gallery forests in maintaining Phlebotominae populations in the dry month, as well as their frequent occurrence in household units in the rainy month. This is the first study to identify Leishmania, Trypanosoma, and Crithidia species in Phlebotominae collected in Palmas, Tocantins, Brazil.
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Animales , Femenino , Psychodidae/clasificación , Psychodidae/parasitología , Leishmania/aislamiento & purificación , Bosques , Pradera , Insectos VectoresRESUMEN
Objective To investigate the characteristics and clinical application value of anti-double stranded DNA antibody de-tected by Crithidia indirect immunofluorescence assay method and enzyme linked immunosorbent assay method.Methods Eighty-five patients with systemic lupus erythematosus,20 disease controls and 75 healthy controls were selected.The serum anti-double stranded DNA antibody was detected simultaneously by the methods of Crithidia indirect immunofluorescence assay and enzyme linked immunosorbent assay and their diagnostic efficacies for detection were compared.Results For each method the positive rate in the systemic lupus erythematosus group was significantly higher than that in the disease control group and healthy control group. The difference had statistical significance (P <0.05).The positive rates of Crithidia indirect immunofluorescence assay and enzyme linked immunosorbent assay in the systemic lupus erythematosus group were 72.94% and 88.24% respectively,and the positive predictive value of enzyme linked immunosorbent assay is lower(P <0.05).Meanwhile the anti-double stranded DNA antibody con-centrations detected by enzyme linked immunosorbent assay method showed statistically significant difference among the active sys-temic lupus erythematosus group,the stable systemic lupus erythematosus group and the control group (P <0.05 )and presented linear trend.Conclusion Using Crithidia indirect immunofluorescence assay method to detect anti-double stranded DNA antibody for the systemic lupus erythematosus group has high specificity and is helpful for the diagnosis of systemic lupus erythematosus. Enzyme linked immunosorbent assay can be used to detect anti-double stranded DNA antibody concentration quantitatively,which is linearly related with systemic lupus erythematosus activity and the method is of high sensitivity,which can effectively screen the pa-tients with systemic lupus erythematosus.
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We analyzed the effect of the combination of citral, eugenol and thymol, respectively the main constituents of essential oils of Cympobogon citratus (DC) Stapf, Poaceae (lemon grass), Syzygium aromaticum (L.) Merr. & L.M. Perry, Myrtaceae (clove) and Thymus vulgaris L., Lamiaceae (thyme), on the proliferation of the trypanosomatids Crithidia fasciculata and Trypanosoma cruzi. The constituents were initially added individually at different concentrations to C. fasciculata cultures to estimate the IC50/24h. Concentrations in a triple combination were about 2 times and 16.5 times lower against C. fasciculata and T. cruzi, respectively, as compared to isolated compounds. Incubation of C. fasciculata with the trypanocydal agent benznidazole did not affect parasite growth at concentrations up to 500 µg/ml, but the IC50 of this drug against T. cruzi was 15.8 µg/ml, a value about 2-5 times higher than that of constituents in the triple combination. Analysis of treated C. fasciculata by scanning electron microscopy showed rounding of the cell body. Our data show that combination of essential oil constituents resulted in increased inhibitory activity on growth of both non-pathogenic and pathogenic trypanosomatid species and indicate that the non-patogenic C. fasciculata may represent a resistant model for drug screening in trypanosomatids.
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Objective: To determine the cut-off point of anti-dsDNA for screening by EliA dsDNA. Methods: Serum specimens requested for anti-dsDNA between October and December 2007 were recruited and tested by the Crithidia luciliae immunofluorescence test (CLIFT) and automated fluorescence immunoassay (EliA dsDNA). The CLIFT was considered as the gold standard method. Different levels of sensitivity and specificity were determined and the cut-off point was selected from among them. Results: Of the 133 specimens collected, 35 were positive whereas 98 were negative with the CLIFT. Of those 35 positive specimens, 2, 0, 2, 2 and 29 were, respectively, in ranges of < 5, 5 to 9.9, 10 to 14.9, 15 to 19.9 and > 20 IU/ml by EliA dsDNA. Also, of the 98 negative specimens, 73, 7, 4, 4 and 10 were, respectively, in ranges of < 5, 5 to 9.9, 10 to 14.9, 15 to 19.9 and > 20 IU/ml by EliA dsDNA. The sensitivity and specificity for each level were determined and the value of 11 IU/ml was selected as the cut-off point. Additionally, when clinical diagnosis was used in specimens with discrepant results, the sensitivity of EliA dsDNA was far better than the CLIFT, whereas the specificity of both methods was comparable. Conclusion: The appropriate cut-off point of EliA dsDNA for screening was 11 IU/ml. Furtermore, the diagnostic value of EliA dsDNA was better than the CLIFT when clinical diagnosis was included in the gold standard criteria.
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BACKGROUND: Anti-double stranded DNA antibody (anti-dsDNA) test is useful for the diagnosis and monitoring of systemic lupus erythematosus (SLE). Although several methods are available, none of them is completely satisfactory and differences among them have been reported. We evaluated the diagnostic performance of 6 commercial kits for anti-dsDNA detection. METHODS: A total of 142 sera (SLE [N=74], other systemic rheumatic diseases [N=50], other diseases [N=18]) were tested by 6 different assay kits using different antigenic sources of DNA: Crithidia luciliae immunofluorescence test (CLIFT), salmon testes (immunoblot, IB), human (ELISA I), salmon testes with nucleosome linker (ELISA II), plasmid (ELISA III), and synthetic oligonucleotides (chemiluminescence immunoassay, CLIA). RESULTS: With manufacturers' cut-off values, 6 test kits showed sensitivities of 55.4-91.9%. ELISA I had a greater sensitivity than the other five assays (P0.05). With cut-off values set at 95% of specificity, ELISA II had a higher sensitivity than ELISA III (63.5% vs. 41.9%, P<0.05). IB had poor concordance rates with other assays (42.0-65.0%). Pearson correlation coefficients among 4 quantitative assays were 0.667-0.798. CONCLUSIONS: Six different assays showed various performances depending on the methods and cut-off values used. Except IB, the other five assays can be used for the detection of anti-dsDNA.
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Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Anticuerpos Antinucleares/análisis , Área Bajo la Curva , Mediciones Luminiscentes/métodos , ADN/inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Técnica del Anticuerpo Fluorescente/métodos , Immunoblotting/métodos , Lupus Eritematoso Sistémico/diagnóstico , Curva ROC , Juego de Reactivos para Diagnóstico , Sensibilidad y EspecificidadRESUMEN
The presence of anti-dsDNA is included in diagnostic criteria for systemic lupus erythematosus (SLE) according to the American College of Rheumatology (ACR). It has been the most useful factor in the diagnosis, prognosis, and therapeutic monitoring of patients with SLE. A number of methods are available but radioimmunoassay (RIA) has been regarded as standard method. A shift from RIAs to nonisotopic assay has been observed with other tests. Still, RIA assays are standard methods for anti-nDNA antibodies. A comparative study of the Crithidia luciliae immunofluorescence (CLIF) assay and an RIA was made. METHOD: Sera from 144 patients were tested by an indirect immunofluorescent antibody technique employing Crithidia luciliae and IT-1 cell lines as a substrate and radioimmunoassay was based on the Farr technique. RESULTS: 1. Thirty-nine of 122 sera with positive antinuclear antibody (ANA) tests had the possibility of positive anti-nDNA antibodies. 2. The RIA was positive in 54 sera, and 37 of these showed a discrepancy between the RIA and the ANA pattern (false positive rate 25.7%). 3. The CLIF was positive in 15 sera, and 5 of these showed a discrepancy between CLIF and the ANA pattern (false positive rate 3.5%). 4. Only CLIF was positive in 2 sera of which one showed a discrepancy between CLIF and the ANA pattern. 5. Only RIA was positive in 41 sera, and 33 of these showed a discrepancy between RIA amp; the ANA pattern. CONCLUSION: The immunofluorescence assay using Crithidia luciliae is a valid method to detect anti-dsDNA antibodies and has a much lower false positive rate compared with RIA. The simple and inexpensive CLIF test could either replace the RIA in clinical laboratories or be used in conjunction with the ANA pattern as a confirmatory test for antibodies to nDNA.
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Humanos , Anticuerpos , Anticuerpos Antinucleares , Línea Celular , Crithidia , Diagnóstico , Técnica del Anticuerpo Fluorescente , Lupus Eritematoso Sistémico , Pronóstico , Radioinmunoensayo , ReumatologíaRESUMEN
Na pesquisa de anticorpos anti-DNA podem ser utilizadas várias metodologias como a imunofluorescência indireta (IFI), enzimaimunoensaio (ELISA) ou radioimunoensaio (RIE) com DNA marcado com 14C, sendo que a IFI empregando Crithçidia luciliae como substrato é a mais utilizada. Sendo este um parasita flagelado da família dos tripanosomatídeos, apresenta estruturas antigênicas comuns ao Trypanosoma cruzi. Portanto, soros de pacientes com sorologia positiva para Doença de Chagas (DC) podem apresentar uma reatividade cruzada entre estes parasitas, constituindo um fator interferente na reação de IFI para pesquisa de anticorpos anti-DNA. Com o objetivo de verficar a freqüência com que esta inferência ocorre na rotina laboratorial, analisou-se os resultados obtidos na pesquisa de anti-DNA por IFI realizadas no período de junho de 1994 a julho de 1995 no Setor de Imunologia Clínica do Hospital Universitário Regional do Norte do Paraná, Londrina-Paraná. Das 927 reações realizadas, 60 (6,47%) foram reagentes, 832 (89,75%) não reagentes e 35 (3,77%) apresentaram um padrão inespecífico de fluorescência. Suspeitando-se de reatividade cruzada, foram realizadas reações sorológicas para DC (HAI e IFI) nestas amostras, sendo que 100% apresentaram resultados reagentes para ambas as reações. Estes dados confirmam a interferência dos anticorpos anti-Trypanosoma cruzi na pesquisa de anticorpos anti-DNA por IFI e alertam para a necessidade da confirmação de resultados falsos-positivos, principalmente em regiões onde a DC é endêmica.