Increased Natural Killer (NK)-cell cytotoxicity and Trypanosoma cruzi-specific memory B cells in subjects with discordant serology for Chagas disease.

The presence of memory T cell specific for Trypanosoma cruzi in subjects with discordant serology for Chagas disease supports a cleared infection in these subjects. Using high-dimensional flow cytometry, ELISPOT assays and quantitative PCR, antibody-secreting cells and memory B cells specific for T. cruzi, total B-cell phenotypes, innate immune responses and parasite DNA were evaluated in serodiscordant, seropositive and seronegative subjects for T. cruzi infection. T. cruzi-specific memory B cells but no antibody-secreting cells specific for T. cruzi, increased proportion of nonclassical monocytes and increased levels of polyfunctional NK cells were found in serodiscordant compared with seropositive subjects. None of the serodiscordant subjects evaluated showed detectable parasite DNA, most of them did not show cardiac abnormalities and a group of them had had confirmed positive serology for Chagas disease. The unique immune profiles in serodiscordant subjects support that T. cruzi infection was cleared or profoundly controlled in these subjects.

Molecular Characterization of Trypanosoma cruzi Reactivation and Follow-up in a Case Series of People With HIV.

We characterize Trypanosoma cruzi infections from blood and cerebrospinal fluid samples in a case series of people with human immunodeficiency virus and Chagas disease. We identify different infecting T. cruzi populations, highlighting the usefulness of real-time polymerase chain reaction for Chagas disease reactivation diagnosis and evaluation of treatment response.

Prospective multicenter evaluation of real time PCR Kit prototype for early diagnosis of congenital Chagas disease.

BACKGROUND: Current algorithm for Congenital Chagas Disease (cCD) diagnosis is unsatisfactory due to low sensitivity of the parasitological methods. Moreover, loss to follow-up precludes final serodiagnosis after nine months of life in many cases. A duplex TaqMan qPCR kit for Trypanosoma cruzi DNA amplification was prospectively evaluated in umbilical cord (UCB) and peripheral venous blood (PVB) of infants born to CD mothers at endemic and non-endemic sites of Argentina. METHODS: We enrolled and followed-up 370 infants; qPCR was compared to gold-standard cCD diagnosis following studies of diagnostic accuracy guidelines. FINDINGS: Fourteen infants (3·78%) had cCD. The qPCR sensitivity and specificity were higher in PVB (72·73%, 99·15% respectively) than in UCB (66·67%, 96·3%). Positive and negative predictive values were 80 and 98·73% and 50 and 98·11% for PVB and UCB, respectively. The Areas under the Curve (AUC) of ROC analysis for qPCR and micromethod (MM) were 0·81 and 0·67 in UCB and 0·86 and 0·68 in PVB, respectively. Parasitic loads ranged from 37·5 to 23,709 parasite equivalents/mL. Discrete typing Unit Tc V was identified in five cCD patients and in six other cCD cases no distinction among Tc II, Tc V or Tc VI was achieved. INTERPRETATION: This first prospective field study demonstrated that qPCR was more sensitive than MM for early cCD detection and more accurate in PVB than in UCB. Its use, as an auxiliary diagnostic tool to MM will provide more accurate records on cCD incidence. FUNDING: FITS SALUD 001-CHAGAS (FONARSEC, MINCyT, Argentina) to the Public-Private Consortium (INGEBI-CONICET, INP-ANLIS MALBRAN and Wiener Laboratories); ERANET-LAC-HD 328 to AGS and PICT 2015-0074 (FONCYT, MinCyT) to AGS and FA.

New Scheme of Intermittent Benznidazole Administration in Patients Chronically Infected with Trypanosoma cruzi: a Pilot Short-Term Follow-Up Study with Adult Patients.

There is a clinical need to test new schemes of benznidazole administration that are expected to be at least as effective as the current therapeutic scheme but safer. This study assessed a new scheme of benznidazole administration in chronic Chagas disease patients. A pilot study with intermittent doses of benznidazole at 5 mg/kg/day in two daily doses every 5 days for a total of 60 days was designed. The main criterion of response was the comparison of quantitative PCR (qPCR) findings prior to and 1 week after the end of treatment. The safety profile was assessed by the rate of suspensions and severity of adverse effects. Twenty patients were analyzed for safety, while qPCR was tested for 17 of them. The average age was 43 ± 7.9 years; 55% were female. Sixty-five percent of treated subjects showed detectable qPCR results prior to treatment of 1.45 (0.63 to 2.81) and 2.1 (1.18 to 2.78) parasitic equivalents per milliliter of blood (par.eq/ml) for kinetoplastic DNA (kDNA) qPCR and nuclear repetitive sequence satellite DNA (SatDNA) qPCR, respectively. One patient showed detectable PCR at the end of treatment (1/17), corresponding to 6% treatment failure, compared with 11/17 (65%) patients pretreatment (P = 0.01). Adverse effects were present in 10/20 (50%) patients, but in only one case was treatment suspended. Eight patients showed mild adverse effects, whereas moderate reactions with increased liver enzymes were observed in two patients. The main accomplishment of this pilot study is the promising low rate of treatment suspension. Intermittent administration of benznidazole emerges a new potential therapeutic scheme, the efficacy of which should be confirmed by long-term assessment posttreatment.