Polimorfismos do receptor para quimiocinas (DARC) na infecção por Trypanosoma Cruzi: avaliação na presença e ausência de cardiopatia chagásica crônica

Abstract

The Duffy histo-blood group antigens, with moderate immunogenic transmembrane glycoprotein, encoded by the alleles FYA and FYB, were identified as receptors for chemokines and, therefore, called DARC (Duffy Antigen / Receptor for Chemokine). The link of this receptor with 16 inflammatory chemokines has already been proved. The Duffy antigen may be involved when "sweeping" the excess of these inflammatory mediators from sites of inflammation and, possibly reducing the damage caused by this exacerbated production. The inflammatory chemokines play an important role in regulating the immune response, however, when produced in excess, they may contribute to tissue lesions observed in Chronic chagasic cardiomyopathy (CCC), which is most prevalent form of Chagas disease. This pathology is the result of an inflammatory process, since one of the pathological characteristics is the presence of a large number of inflammatory cells in the myocardium, which are characterized by the presence of diffuse myocarditis with an intense myocardial remodeling, fibrosis, hypertrophy and lesion of the cardiac muscle fibers. Experiments conducted with some chemokines and CCC showed that elevated plasma levels of these inflammatory mediators were associated with the severity of disease in these patients. The local production of chemokines may also be extremely important in cardiac damage observed in CCC. Objectives: To determine if there are differences in the genotypic profile of DARC among T.cruzi-seropositive individuals, with and without CCC and, to verify if there is an association of these patients genotypes with the degrees of the disease severity, as well as to investigate the association between gender and age of individuals and CCC. Methods: The study included 95 individuals, among them 74 were patients, who presented the clinical form of Chronic chagasic cardiomyopathy, and 21 individuals without detectable cardiac manifestations. The molecular analysis was performed by Polymerase Chain Reaction - Restriction Fragment Length Polymorphism (PCR-RFLP). Data were evaluated by multiple logistic regression and Chi-square or Fisher's exact test. Results: Our results did not show either any significant association between the genotypic profile of DARC and the CCC, or with the patients genotypes and the degrees of myocarditis. The degrees of severe and moderate severity were more frequent in patients aged less than or equal to 60 years of age, p = 0.0098. . The male gender was a predictor factor for the CCC (OR = 3.87, 95% CI: 1.30-11.56; p=0.015). Conclusion: There was neither an association between the differences in the genotypic profile of DARC and the CCC, nor with the patients genotypes and the degree of severity of myocarditis. Patients aged less than or equal to 60 years of age presented an increased risk of developing the most severe forms of the cardiopathy and, male gender was also associated with increased risk for CCC.