Identificação de parâmetros imunológicos, nutricionais e parasitológicos (S. mansoni) em um estudo caso-controle associado à hanseníase

Abstract

Leprosy, an age-old and stigmatizing disease presented in 2018 a global prevalence of 184.212 cases, with Brazil being the second country with the highest number of new cases. Control actions are based on the diagnosis, treatment and surveillance of contacts. However, this disease requires more innovative approaches to real control. It is known that infections caused by parasites as well as micronutrient deficiencies can coexist with leprosy in endemic areas in Brazil. Chronic helminth infections and malnutrition appear to be associated with suppression of the immune response. Thus, it is proposed to determine risk factors associated with leprosy in a study group considering socio-demographic, immunological, hematological, parasitological (S. mansoni) and nutritional variables. Three groups were included, cases (with leprosy PB, MB, n = 79), contacts (asymptomatic, history of living with the patient, n = 97) and negative control (asymptomatic without history of leprosy, n = 81), attended at ESF in Gov. Valadares and Limeira de Mantena. Structured questionnaires were applied and after collection of blood and feces, laboratory tests were carried out to assess serological reactivity (IgG4- Swap), determine the immunological profile, blood count and micronutrient quantification. Different statistical tests were applied for analysis. The low level of education of the participants was highlighted. 75% (33) of the co-infected individuals had a basic level of education and only 7.9% (14) of the control group (contacts and negative control) had higher education. 70% of the individuals in the contact group lived with the patient and 68% of the individuals in the co-infected group were not in the habit of treating drinking water. There was no association between leprosy of the multibacillary clinical form and schistosomiasis, however we found a strong correlation between leprosy and infection by S. mansoni with an aOR of 3.37 comparing the group of cases and controls and even stronger, an aOR of 8, 33 comparing cases and contacts. Probably, our limitation in finding an association between leprosy in the multibacillary form and schistosomiasis is due to the small number of cases with positive BI and also the small number of participants with active schistosomiasis and still presenting low parasitic burden. In the cytokine panel, it was found that IL-10, an immunoregulatory cytokine, was associated with group of infected individuals (S. mansoni) as well as with the co-infected group x negative control (ML stimulus) and mono infected (SE, PHA and ML). IL-4 was also associated with the co-infected x contact (SE) and mono-infected (ML) group. These data reinforce the presence of immunoregulatory and Th2-related cytokines in the co-infected group. Furthermore, through logistic regression, a positive correlation between pro-inflammatory cytokine profile (IL-17, IFN-γ, TNF-α, IL-6 and IL-2) and control group was found. When the group of co-infected and mono-infected was compared, an association of these cytokines with the mono-infected was detected. An association of chemokines IL-8 and IP-10 with the group of mono-infected was observed. Co-infected had inadequate concentrations of vitamin D, and adequate concentrations of vitamin A were observed in the negative control and contact groups. Iron deficiency associated with a poorly diversified diet, together with co-infection, may be the cause of anemia seen in 55% of individuals in the co-infected group who had hematological parameters (red blood cells, hemoglobin and hematocrit) below normal values. We believe that the continuity of these studies and the monitoring of contacts are relevant to better delineate risk factors.