Background: Celiac disease is an immune-mediated enteropathy caused by the ingestion of gluten, a protein fraction found in certain cereals. Immunotoxic gluten peptides that are recalcitrant to degradation of digestive enzymes appear to trigger celiac syndromes. A 33-mer peptide from α-2 gliadin has been identified as a principal contributor to gluten immunotoxicity. A gluten-free diet is the usual first therapy for celiac disease patients; therefore, the characterization and quantification of the toxic portion of the gluten in foodstuffs is crucial to avoid celiac damage. Objective: We aimed to develop immunologic assays as a novel food analysis tool for measuring cereal fractions that are immunotoxic to celiac disease patients. Design: The design focused on the production of monoclonal antibodies against the gliadin 33-mer peptide and the development of enzyme-linked immunosorbent assays (ELISAs) and Western blot analysis with the use of novel antibodies. Results: A sandwich ELISA method showed a detection limit for wheat, barley, and rye of <1 ppm prolamine. However, the method required a sample that was ≥1 order of magnitude greater for the detection of low-toxic oats, and there was no signal with the safe cereals maize and rice. A competitive ELISA method was also developed for detection of the toxic peptide in hydrolyzed food, which had a detection limit of <0.5 ppm gliadin. Conclusions: Both ELISAs designed for use with the toxic gliadin 33-mer peptide suggested a high correlation between the presence of the peptide and the amount of cereal that was toxic to celiac disease patients. The sensitivity was significantly higher than that of equivalent methods recognizing other gluten epitopes.
3 March 2014 in Expert Review of Anti-infective Therapy
The most neglected aspects of Chagas disease (CD) have been patient care and treatment. Despite recent progress in the development of potentially improved drugs, there is no consensus among different research groups on the lack of therapeutic response markers to evaluate efficacy of newly proposed drugs early after treatment. A systematic review of current evidence regarding molecules which are potential biomarkers for therapeutic response has been conducted using quality assessment and target responses as primary criteria. The review provides a panorama of the cumulative evidence and specific needs for development of a battery of complementary biomarkers which together fulfill ideal or acceptable criteria to evaluate early responses to treatment for chronic CD. There are several marker candidates which together may fulfill acceptable criteria to indicate the efficacy of a trypanocidal treatment. Data from ongoing studies are considered essential to improve assessment of existing markers and to identify those for early follow-up of treated patients.
28 April 2015 in Memórias do Instituto Oswaldo Cruz
The definition of a biomarker provided by the World Health Organization is any substance, structure, or process that can be measured in the body, or its products and influence, or predict the incidence or outcome of disease. Currently, the lack of prognosis and progression markers for chronic Chagas disease has posed limitations for testing new drugs to treat this neglected disease. Several molecules and techniques to detect biomarkers in Trypanosoma cruzi-infected patients have been proposed to assess whether specific treatment with benznidazole or nifurtimox is effective. Isolated proteins or protein groups from different T. cruzi stages and parasite-derived glycoproteins and synthetic neoglycoconjugates have been demonstrated to be useful for this purpose, as have nucleic acid amplification techniques. The amplification of T. cruzi DNA using the real-time polymerase chain reaction method is the leading test for assessing responses to treatment in a short period of time. Biochemical biomarkers have been tested early after specific treatment. Cytokines and surface markers represent promising molecules for the characterisation of host cellular responses, but need to be further assessed.
Background. In this longitudinal cohort study we evaluated the congenital transmission of Chagas disease (CD) in a nonendemic area. The aim of this work was to analyze the predictive value of a Trypanosoma cruzi–positive polymerase chain reaction (PCR) result in pregnant women for the diagnosis of vertical transmission and to evaluate the use of PCR as a tool for early detection of infection. Methods. The offspring of 59 seropositive pregnant mothers were followed up. The parasitological status of mothers was studied by PCR in a total of 64 pregnancies; 10 of these women had received treatment before pregnancy. Sixty-five infants (including a pair of twins) were monitored at 0, 6, 9, and 12 months of age by PCR and serology. In cases of congenital transmission, hemoculture and parasite lineage typing were performed. Results. Nine infants had acquired CD congenitally. This represents a transmission rate of 13.8% among seropositive mothers (9 infected newborns of 65 total live births). All infants were infected with T. cruzi discrete typing unit V strain. A statistically significant correlation was found between T. cruzi vertical transmission and a positive PCR result during pregnancy (31%; 9 infected newborns in 29 live births). No infected infants were detected among 10 mothers who were treated before they became pregnant, compared with 16.4% (9 of 55 live births) among untreated mothers. Conclusions. PCR is a useful tool for the detection of congenital CD, and the treatment of infected women of childbearing age seems to be useful for preventing vertical transmission.
Murine immunization withTrypanosoma cruzi KMP11-HSP70fused genes but not theKMP11gene alone elicited both an immunoglobulin G2a long-lasting humoral immune response against KMP11 protein and activation of CD8+cytotoxic T lymphocytes specific for two KMP11 peptides containing A2 motifs. Moreover, protection against the parasite challenge was observed after immunization with the chimeric gene.