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Clinical and serological screening for Leprosy by samples from the COVID-19 survey in Ribeirão Preto

Abstract

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, which infects skin cells and peripheral nerves. The main consequence of the disease is deformities, leading to physical disability. The difficulties of health services regarding the diagnosis of different clinical forms, reactional states and an early identification of infected contacts are important factors that do not allow us to control the magnitude that this disease represents in Brazil. This reality was consolidated in the face of the results obtained by the implementation actions carried out in Jardinópolis since 2015, mainly through the training of health teams, administration of the Leprosy Suspicion Questionnaire (QSH) focusing on neurological symptoms, anti-PGL-I serology, diagnosis by molecular biology RLEP-PCR that indicates an occult endemic for leprosy, ranging from low endemic in 2014 (prevalence 0.74 / 10,000 inhabitants) to hyperendemic in 2016 (23.61 / 10,000 inhabitants), in a state said to be non-endemic since 2006, as per publications by Bernardes-Filho et al (2017; 2020, 2021). Highlightly, there are current limitations of laboratory tests to diagnosis, monitoring in leprosy and seroprevalence studies in the health care network to assess contacts and/or infection with subclinical infection. The application of surface protein Mce1A and PGL-I may lead to a possible advance for prospecting serological assays by ELISA and lateral flow immunochromatography tests. Mce1A (52 kD) is a cell wall protein of the Mycobacterium genus, which confers great capacity for adherence, invasion and connections in host cells, as well as the production of adequate antibodies (IgA, IgM and IgG) against the protein. Pleliminary studies have demonstrated high levels of anti-Mce1A antibodies in leprosy cases as compared to household contacts and endemic controls (p<0.0001). Anti-PGL-I and RLEP-PCR are already available as subsidiary tests for the diagnosis of leprosy cases at the National Reference Center on Leprosy of HCFMRP-USP, constituting tools for screening and identification of those at high risk of disease development. Therefore, there is a need to validate these new anti-Mce1A markers using a larger sample size and in different groups of endemic profiles. To this end, a new retrospective cross-sectional study will be carried out with those collected through the project carried out in 2020 entitled "Assessment of the prevalence of virological and serological markers of SARS-CoV-2 in the population of Ribeirão Preto: an epidemiological survey", in which they were collected blood and nasal swab from 709 belonging to different census districts of the city. Laboratory assays consist of evaluating the humoral immune response by searching for IgA, IgM, total IgG anti-Mce1A, anti-PGL-I and dermal scrapings for RLEP-PCR to trace the areas of the greatest risk for leprosy in Ribeirão Preto, to improve the understanding of the role of these antigens in the pathogenesis of leprosy, in addition to identifying possible biomarkers for the implementation of low-cost and easy-to-perform diagnostic platforms by primary and special care centers, an important technological advance for the early diagnosis of leprosy, contributing to break directly the chain of transmission of the disease, and consequently preventing deformities, disability and the maintenance of the stigma of leprosy. (AU)

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