O uso do epítopo alfa-gal no diagnóstico sorológico da infecção crônica por Trypanosoma cruzi

Abstract

The diagnosis of Trypanosoma cruzi infection in the chronic phase are based on the detection of IgG anti-T. cruzi antibody produced by infected individuals, generally using protein antigens. However, the use of carbohydrate antigens present on the surface of the parasite has demonstrated great potential for this purpose. Thus, this work aimed to evaluate the performance of Qβ(α-Gal)540 in the serological diagnosis of chronic T. cruzi infection and the production of IgG anti-α-Gal antibody in individuals treated with benznidazole. A total of 118 samples from individuals with reactive serology and 46 non-reactive for T. cruzi were tested against antigens obtained from the total extract of epimastigote forms of T. cruzi and Qβ(αGal)540, as well as 81 samples from 22 patients undergoing etiological treatment with benznidazole. The results showed a significant difference between the groups of individuals with reactive and non-reactive serology for both antigens, and no sample from negative individuals showed reactivity against the Qβ(α-Gal)540, showing values of 100% for specificity and positive predictive value. Regarding sensitivity, the total antigen obtained 55.1%, while Qβ(α-Gal)540 presented 89%. The other parameters analyzed also showed a better result for the Qβ(α-Gal)540 antigen, with a negative predictive value and accuracy of 78% and 92.1%, respectively. The IgG anti-α-Gal and IgG anti-T. cruzi antibodies against Qβ(α-Gal)540 and epimastigotes antigen, respectively, showed no difference regarding the reactivity profile before and after the treatment with benznidazole. Thus, Qβ(α-Gal)540 presents itself as a potential antigenic alternative in the diagnosis of chronic T. cruzi infection, reinforcing the need for other studies that explore its application in extended to the population from other geographic regions.