Resposta imuno-alérgica de pacientes com esquistossomose em região de baixa endemicidade

Abstract

Schistosomiasis is a parasitic disease caused by flatworms, Schistosoma genus and, although not a disease that causes a high death toll, presents a framework for significant morbidity. In Ceará, Maranguape city has the location with higher positive for schistosomiasis in the state, called Planalto do Cajueiro. Several population studies showing an inverse relationship between parasites and the development of allergic diseases, has raised speculations about a protective effect (or immunomodulating) of parasites in relation to atopy. According to the Hygiene Hypothesis, the lack of intense infections, hygiene, vaccination and antibiotic use, mainly present in developed countries, can modify the immune system, which is responding inadequately to some substances. This study aimed to evaluate the immune-allergic reactions of patients diagnosed with schistosomiasis, living in an area of low endemicity. Therefore, we performed first the parasitological diagnosis of schistosomiasis by the Kato-Katz and later diagnosed with other parasitic diseases by Lutz’s method. At the end of the sampling, 39 patients were found positive for schistosomiasis and we randomly selected 52 patients negative for this disease. A blood collection was performed in all 91 patients for complete blood count, IgE, IgG anti-S.mansoni and counting of lymphocyte subpopulations by flow cytometry. Furthermore, Prick test were performed, using five environmental allergens. Of the 39 subjects in the (S.mansoni) positive group, only 7 were positive to Prick test, while the 52 subjects in the negative (S.mansoni), 20 had some kind of reaction. Eosinophilia and increased levels of IgE were shown in allergic and S.mansoni infected patients. The profile of lymphocytes in infected patients showed an increased number of cells CD3 + CD4 + and CD3 + CD8 +. Based on these results we conclude that: The presence of infection by S. mansoni showed to be a protective factor for the development of allergy; the increased concentration of IgE is directly related to allergic and parasitic diseases, with a higher concentration of eosinophils in infected patients, patients infected with S. mansoni developed an increased number of cells CD3 + CD4 + and CD3 + CD8 +, and the development of allergic reactions was inversely proportional to age of individuals. Further studies of the mechanisms involved in this parasite relationship can contribute to the development new treatments for allergy.