RESUMO
Underdiagnosis of chronic infection with the nematode Strongyloides stercoralis may lead to severe disease in the immunosuppressed. Thus, we have set-up a specific and highly sensitive molecular diagnosis in stool samples. Here, we compared the accuracy of our polymerase chain reaction (PCR)-based method with that of conventional diagnostic methods for chronic infection. We also analyzed clinical and epidemiological predictors of infection to propose an algorithm for the diagnosis of strongyloidiasis useful for the clinician. Molecular and gold standard methods were performed to evaluate a cohort of 237 individuals recruited in Buenos Aires, Argentina. Subjects were assigned according to their immunological status, eosinophilia and/or history of residence in endemic areas. Diagnosis of strongyloidiasis by PCR on the first stool sample was achieved in 71/237 (29.9%) individuals whereas only 35/237(27.4%) were positive by conventional methods, requiring up to four serial stool samples at weekly intervals. Eosinophilia and history of residence in endemic areas have been revealed as independent factors as they increase the likelihood of detecting the parasite according to our study population. Our results underscore the usefulness of robust molecular tools aimed to diagnose chronic S. stercoralis infection. Evidence also highlights the need to survey patients with eosinophilia even when history of an endemic area is absent.
Assuntos
Testes Diagnósticos de Rotina , Eosinofilia/sangue , Fezes/parasitologia , Larva , Strongyloides stercoralis/genética , Strongyloides stercoralis/isolamento & purificação , Estrongiloidíase/diagnóstico , Adolescente , Adulto , Idoso , Algoritmos , Animais , Argentina , Estudos de Coortes , Doenças Endêmicas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Reprodutibilidade dos Testes , Adulto JovemRESUMO
Several Trypanosoma cruzi molecules that stimulate macrophages activity were described as Toll-like receptor 2 (TLR2) ligands. Besides, the models of dendritic cells (DC) are poorly characterised. We have previously demonstrated that live-trypomastigotes (Tp) plus lipopolysaccharide (LPS) induce DC with tolerogenic properties that produce high levels of interleukin (IL)-10 and an impaired capacity to induce lymphoproliferation. Here, we show that the regulatory phenotype was observed with heat-killed trypomastigotes (Tphk) stimulation, ruling out DC infection. T. cruzi induced a particular DC activation state increasing LPS-activation of extracellular regulated kinase (ERK) 1/2 and signal transducer and activator of transcription (STAT) 3. Inhibition of ERK down-regulated IL-10 production and restored DC stimulatory capacity, showing the importance of this pathway in the DC modulation. A recent work shows that signalling via TLR4 and TLR2 induces a synergism in anti-inflammatory cytokine production in murine DC. Upon TLR2 and TLR4 stimulation using Pam(3)Cys or LPS and Tphk in DC from TLR2 knock out (KO) or TLR4-mutant mice, we showed that high levels of IL-10 were independent of TLR2 but associated with TLR4 and NF-kappaB signallization. Although sialic acid has been described as a molecule responsible of DC inhibition, we determine that it is not associated with T. cruzi-IL-10 modulatory response. In conclusion, all these findings demonstrate a key role of ERK and TLR4 in association with NF-kappaB in IL-10 modulation induced by T. cruzi and suggest that this regulatory effect involves parasite-DC interactions not described yet.
Assuntos
Células Dendríticas/imunologia , MAP Quinases Reguladas por Sinal Extracelular/fisiologia , Interleucina-10/biossíntese , Receptor 4 Toll-Like/fisiologia , Trypanosoma cruzi/imunologia , Animais , Células Cultivadas , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Endogâmicos , Ácido N-Acetilneuramínico/fisiologia , NF-kappa B/fisiologia , Fosforilação , Fator de Transcrição STAT3/metabolismo , Receptor 2 Toll-Like/fisiologiaRESUMO
En la actualidad existe consenso en el papel que las características de la población de Trypanosoma cruzi tienen en la patogésesis de las distintas formas clínicas de la enfermedad de Chagas. En nuestro laboratorio, estudiamos en el modelo murino las consecuencias de la infección con dos poblaciones de características biológicas polares: RA y CA-I. Demostramos que el daño neuromuscular es, en parte, mediato por diferentes subpoblaciones de linfocitos T. Además, observamos que el fenotipo celular responsable de la patologia y los distintos blancos tisulares dependen de la población parasitaria. A pesar de no haber observado diferencias en la reactividad jugaría un papel adicional en el desarrollo de la patología neuromuscular: sueros de ratones infectados con RA, pero no con CA-I, desencadenaron alteraciones en el potencial de acción nerviosa. También hemos detectado, en el modelo murino, una disminución en la fertilidad de las hembras infectadas con CA-I/K-98, mientras las hembras infectadas con RA se comportaron igual a los controles. Sin embargo, sólo pudo comprobarse pasaje transplacentario de T. cruzi en la cepa RA. Las diferencias encontradas en la fertilidad, en la sobrevida de las crías nacidas de madres infectadas, así como en el número de resorciones fetales detectadas con la cepa miotrópica, podrían atribuirse a la respuesta inflamatoria hallada en el útero de estas hembras, ya que no se observaron alteraciones en el estro de ambos grupos infectados con respecto a los controles.