Role of T. cruzi exposure in the pattern of T cell cytokines among chronically infected HIV and Chagas disease patients.

OBJECTIVES: The impact of Chagas disease (CD) in HIV-infected patients is relevant throughout the world. In fact, the characterization of the adaptive immune response in the context of co-infection is important for predicting the need for interventions in areas in which HIV and Chagas disease co-exist. METHODS: We described and compared the frequency of cytokine-producing T cells stimulated with soluble antigen of Trypanosoma cruzi (T. cruzi) using a cytometric assay for the following groups: individuals with chronic Chagas disease (CHR, n=10), those with Chagas disease and HIV infection (CO, n=11), those with only HIV (HIV, n=14) and healthy individuals (C, n=15). RESULTS: We found 1) a constitutively lower frequency of IL-2+ and IFN-γ+ T cells in the CHR group compared with the HIV, CO and healthy groups; 2) a suppressive activity of soluble T. cruzi antigen, which down-regulated IL-2+CD4+ and IFN-γ+CD4+ phenotypes, notably in the healthy group; 3) a down-regulation of inflammatory cytokines on CD8+ T cells in the indeterminate form of Chagas disease; and 4) a significant increase in IL-10+CD8+ cells distinguishing the indeterminate form from the cardiac/digestive form of Chagas disease, even in the presence of HIV infection. CONCLUSIONS: Taken together, our data suggest the presence of an immunoregulatory response in chronic Chagas disease, which seems to be driven by T. cruzi antigens. Our findings provide new insights into immunotherapeutic strategies for people living with HIV/AIDS and Chagas disease.

Role of T. cruzi exposure in the pattern of T cell cytokines among chronically infected HIV and Chagas disease patients

OBJECTIVES: The impact of Chagas disease (CD) in HIV-infected patients is relevant throughout the world. In fact, the characterization of the adaptive immune response in the context of co-infection is important for predicting the need for interventions in areas in which HIV and Chagas disease co-exist. METHODS: We described and compared the frequency of cytokine-producing T cells stimulated with soluble antigen of Trypanosoma cruzi (T. cruzi) using a cytometric assay for the following groups: individuals with chronic Chagas disease (CHR, n=10), those with Chagas disease and HIV infection (CO, n=11), those with only HIV (HIV, n=14) and healthy individuals (C, n=15). RESULTS: We found 1) a constitutively lower frequency of IL-2+ and IFN-γ+ T cells in the CHR group compared with the HIV, CO and healthy groups; 2) a suppressive activity of soluble T. cruzi antigen, which down-regulated IL-2+CD4+ and IFN-γ+CD4+ phenotypes, notably in the healthy group; 3) a down-regulation of inflammatory cytokines on CD8+ T cells in the indeterminate form of Chagas disease; and 4) a significant increase in IL-10+CD8+ cells distinguishing the indeterminate form from the cardiac/digestive form of Chagas disease, even in the presence of HIV infection. CONCLUSIONS: Taken together, our data suggest the presence of an immunoregulatory response in chronic Chagas disease, which seems to be driven by T. cruzi antigens. Our findings provide new insights into immunotherapeutic strategies for people living with HIV/AIDS and Chagas disease.

CHAGASIC MENINGOENCEPHALITIS IN AN HIV INFECTED PATIENT WITH MODERATE IMMUNOSUPPRESSION: PROLONGED SURVIVAL AND CHALLENGES IN THE HAART ERA / Meningoencefalite chagásica em paciente infectada pelo HIV com imunodepressão moderada: desafios na era HAART e sobrevida prolongada

The reactivation of Chagas disease in HIV infected patients presents high mortality and morbidity. We present the case of a female patient with confirmed Chagasic meningoencephalitis as AIDS-defining illness. Interestingly, her TCD4+ lymphocyte cell count was 318 cells/mm3. After two months of induction therapy, one year of maintenance with benznidazol, and early introduction of highly active antiretroviral therapy (HAART), the patient had good clinical, parasitological and radiological evolution. We used a qualitative polymerase chain reaction for the monitoring of T. cruzi parasitemia during and after the treatment. We emphasize the potential value of molecular techniques along with clinical and radiological parameters in the follow-up of patients with Chagas disease and HIV infection. Early introduction of HAART, prolonged induction and maintenance of antiparasitic therapy, and its discontinuation are feasible, in the current management of reactivation of Chagas disease.

A reativação da doença de Chagas em pacientes com a infecção pelo HIV apresenta uma alta morbidade e mortalidade. Neste relato, apresentamos caso confirmado de meningoencefalite chagásica, como doença definidora de aids, em paciente com 318 linfócitos T-CD4+/mm3. Após 2 meses de tratamento seguido de um ano de profilaxia secundária com benzonidazol e início precoce de terapia antirretroviral (HAART), a paciente apresentou boa evolução clínica, parasitológica e radiológica. Utilizamos a reação em cadeia da polimerase qualitativa do T. cruzi, para monitorização da parasitemia por T. cruzi durante e após o tratamento. Ressaltamos o valor potencial das técnicas moleculares associadas aos parâmetros clínicos e radiológicos nos pacientes com doença de Chagas e infecção pelo HIV. A introdução precoce da terapia antirretroviral, a terapia antiparasitária prolongada, manutenção e descontinuação da mesma, são desafios atuais, embora possíveis, no manejo da reativação da doença de Chagas na era das terapias antirretrovirais de alta eficácia.

CHAGASIC MENINGOENCEPHALITIS IN AN HIV INFECTED PATIENT WITH MODERATE IMMUNOSUPPRESSION: PROLONGED SURVIVAL AND CHALLENGES IN THE HAART ERA.

The reactivation of Chagas disease in HIV infected patients presents high mortality and morbidity. We present the case of a female patient with confirmed Chagasic meningoencephalitis as AIDS-defining illness. Interestingly, her TCD4+ lymphocyte cell count was 318 cells/mm3. After two months of induction therapy, one year of maintenance with benznidazol, and early introduction of highly active antiretroviral therapy (HAART), the patient had good clinical, parasitological and radiological evolution. We used a qualitative polymerase chain reaction for the monitoring of T. cruzi parasitemia during and after the treatment. We emphasize the potential value of molecular techniques along with clinical and radiological parameters in the follow-up of patients with Chagas disease and HIV infection. Early introduction of HAART, prolonged induction and maintenance of antiparasitic therapy, and its discontinuation are feasible, in the current management of reactivation of Chagas disease.

Methylene blue vital staining for Trypanosoma cruzi trypomastigotes and epimastigotes

The morphological identification of Trypanosoma cruzi is currently considered to have a high specificity, but its sensitivity, which depends on the volume of the sample examined, is rather low. Trypanosome developmental stages suspended in blood, reduviid feces, and culture media are routinely searched for by means of fresh film examination (about 2 æL). High speed centrifugation of blood samples separates the buffy coat, where most trypomastigotes concentrate. As the parasites are transparent and colorless, their detection is mostly dependent on their motility. The fluorescent vital stain acridine orange has been used to enhance image contrast, as exemplified by the QBC (Quantitative Buffy Coat) technique. Staining blood, buffy coat, reduviid feces, and culture media samples with methylene blue (also a vital dye) is a means of producing sharp, well contrasted images of motile or non-motile T. cruzi developmental stages, only standard laboratory microscopes being required. Slides previously coated with a thin layer of methylene blue are used to stain fresh blood films. Photomicrographs exemplify the results of methylene blue staining applied to living and fixed parasites.

A identificação morfológica de Trypanosoma cruzi tem alta especificidade, segundo é geralmente aceito; entretanto, sua sensibilidade, dependente do volume da amostra examinada, é baixa. Formas evolutivas de T. cruzi suspensas em sangue, fezes de reduviídeos e meios de cultura são rotineiramente pesquisadas em esfregaços a fresco (cerca de 2 æL). Centrifugação de amostras de sangue a altas velocidades produz a separação do creme leucocitário, onde se concentram as formas tripomastigotas. Em preparações a fresco, a motilidade das formas tripomastigotas e epimastigotas de T. cruzi, protozoário transparente e incolor, facilita sua detecção. Laranja de acridina, corante vital fluorescente, tem sido usada para acentuar o contraste das imagens de parasitas. Disto é exemplo a técnica QBC (Quantitative Buffy Coat). A coloração por meio de azul de metileno (também um corante vital), de amostras de sangue, de fezes de reduviídeos ou de meios de cultura permite obter imagens nítidas e contrastadas de formas evolutivas de T. cruzi com ou sem motilidade. Microscópios de uso geral em laboratórios permitem o exame dos parasitas corados. Uma camada bem delgada de azul de metileno colocada sobre a parte central da lâmina limpa (por meio da evaporação de solução diluída do corante) é usada para corar as preparações a fresco. O aspecto dos parasitas corados em materiais frescos ou previamente fixados pode ser observado em fotomicrografias.

Methylene blue vital staining for Trypanosoma cruzi trypomastigotes and epimastigotes.

The morphological identification of Trypanosoma cruzi is currently considered to have a high specificity, but its sensitivity, which depends on the volume of the sample examined, is rather low. Trypanosome developmental stages suspended in blood, reduviid feces, and culture media are routinely searched for by means of fresh film examination (about 2 microL). High speed centrifugation of blood samples separates the buffy coat, where most trypomastigotes concentrate. As the parasites are transparent and colorless, their detection is mostly dependent on their motility. The fluorescent vital stain acridine orange has been used to enhance image contrast, as exemplified by the QBC (Quantitative Buffy Coat) technique. Staining blood, buffy coat, reduviid feces, and culture media samples with methylene blue (also a vital dye) is a means of producing sharp, well contrasted images of motile or non-motile T. cruzi developmental stages, only standard laboratory microscopes being required. Slides previously coated with a thin layer of methylene blue are used to stain fresh blood films. Photomicrographs exemplify the results of methylene blue staining applied to living and fixed parasites.

Avaliação da eficácia da azitromicina e pirimetamina em camundongos infectados por cepa cistogênica de Toxoplasma gondii / Evaluation of the efficacy of azithromycin and pyrimethamine, for treatment of experimental infection of mice with Toxoplasma gondii cystogenic strain

Foi avaliada a eficácia da administração prolongada de azitromicina e pirimetamina em camundongos infectados com cepa cistogênica de Toxoplasma gondii. Os animais foram inoculados intraperitonealmente com um cisto de T. gondii e, após 20 dias, divididos em quatro grupos: GI infectados não tratados, GII infectados e tratados concomitantemente com pirimetamina (12,5mg/kg/dia) e azitromicina (100mg/kg/dia), GIII infectados e tratados com a mesma dose de pirimetamina e GIV infectados e tratados da mesma forma com azitromicina. O tratamento, via oral, estendeu-se por 120 dias; após este período os animais foram sacrificados e foi feita a contagem dos cistos no cérebro. A associação de ambos os medicamentos proporcionou melhores resultados, diminuindo a contagem de cistos no cérebro dos animais tratados de forma concomitante.

[Evaluation of the efficacy of azithromycin and pyrimethamine, for treatment of experimental infection of mice with Toxoplasma gondii cystogenic strain]. / Avaliação da eficácia da azitromicina e pirimetamina em camundongos infectados por cepa cistogênica de Toxoplasma gondii.

The efficacy of prolonged administration of azithromycin and pyrimethamine was evaluated in mice experimentally infected with cystogenic strain of Toxoplasma gondii. The animals were intraperitoneally inoculated with one cyst of T. gondii and after 20 days were allocated into four groups: GI, infected without treatment; GII, infected and treated with the association of pyrimethamine (12.5 mg/kg/day) and azithromycin (100 mg/kg/day); GIII, infected and treated with the same dose of pyrimethamine; and GIV, infected and treated in the same way with azithromycin. The oral treatment lasted 120 days, after this period all the animals were sacrificed and the count of cysts in the brain was done. The association of both drugs provided the best results, by diminishing the cyst count in the brain of the animals treated in this way.

Exacerbation of HIV viral load simultaneous with asymptomatic reactivation of chronic Chagas' disease.

Chronic Trypanosoma cruzi infection can reactivate in patients with immunosuppression related to human immunodeficiency virus (HIV) infection, resulting in severe meningoencephalitis or myocarditis and high parasitemia. The effects of T. cruzi on HIV infection are unknown. We describe an HIV-infected patient with chronic Chagas' disease who experienced an asymptomatic T. cruzi reactivation characterized by the finding of the parasite in direct microscopic examination of blood. The patient's HIV viral load had increased simultaneously with the exacerbation of T. cruzi parasitemia and decreased to previous levels after successful antiparasitic treatment. This otherwise unexplained finding suggests that T. cruzi infection might up-regulate HIV replication, which may affect HIV disease progression. Asymptomatic reactivation of Chagas' disease has not been reported before. This could mean that the severe clinical manifestations related to the reactivation of trypanosomiasis are just the tip of the iceberg.