Associação de isotipos de anticorpos anti-antígeno glicolipídio-fenólico-1 como parâmetro auxiliar no diagnóstico de hanseníase

Abstract

Hansen’s disease (known as leprosy) is an infectious disease caused by Mycobacterium leprae, which shows tropism for cells of the peripheral nervous system, and causes skin lesions. Nowadays, there are two challenges faced in relation to leprosy: late diagnosis and the disease in children. The aim of the present study is to investigate the role of anti-glycophenolic antigen-1 serum antibodies and their use as an auxiliary parameter in the diagnosis of leprosy. Two endemic municipalities (São Gonçalo do Amarante-CE and Rio Largo-AL) and 2 hyperendemic municipalities (Canindé-CE and Santana do Ipanema-AL) were included in the study. Home visits were made to 71 index cases ("any age"), and to 395 intra-household and peri-household contacts (between 4 and 15 years old). The survey of leprosy cases reported in the Notifiable Diseases Information System (SINAN) was used to carry out the visits. Each participant had blood collected after dermatoneurological evaluation. Serum dosage of anti-PGL-1 IgM, IgG and IgA was performed by indirect ELISA. A strong association was found between antibody positivity and multibacillary cases. The odds ratios (OR) were 6.11 (95%CI 3.08 - 12.16) for IgM, 3.31 (1.66 - 6.61) for IgG and 16.97 (95%CI 8.39 - 34.2) for IgA. When IgM was associated with one or more isotypes, the OR was 21.0 (95%CI 10.11-43.64), and when IgG and IgA were associated, the OR was 17.58 (95%CI 6.23 - 49.54). The highest diagnostic sensitivity of 76.0% (95%CI 61.8-86.9) was observed for IgM and the lowest value found was 24.1% (95%CI 13.0 - 38.2), which was observed for IgG + IgA isotypes. Regarding the presumed positive predictive values, the lowest value was obtained for IgM, of 24.7% (95%CI 18.1 - 32.3), and the highest values were observed for IgM associated with one or more isotypes, that is, 60.0% (95%CI 44.3 - 74.3) and for the IgG + IgA isotypes, that is, 66.7% (95%CI 41.0-86.7), respectively. The present work suggests that when two or more isotypes of antibodies are present, the probability of facing a case of leprosy increases.