Seroreactivity to new Mycobacterium leprae protein antigens in different leprosy-endemic regions in Brazil

• Main Authors: Emerith Mayra Hungria, Regiane Morillas de Oliveira, Ana Lúcia Osório Maroclo de Souza, Maurício Barcelos Costa, Vânia Nieto Brito de Souza, Eliane Aparecida Silva, Fátima Regina Vilani Moreno, Maria Esther Salles Nogueira, Maria Renata Sales Nogueira Costa, Sônia Maria Usó Ruiz Silva, Samira Bührer-Sékula, Steven G Reed, Malcolm S Duthie, Mariane Martins de Araújo Stefani
• Format: Article
• Language: English
• Published: Instituto Oswaldo Cruz, Ministério da Saúde 2012-12-01
• Series: Memórias do Instituto Oswaldo Cruz.
• Subjects: leprosy; diagnosis; serology
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762012000900017&lng=en&tlng=en

New Mycobacterium leprae protein antigens can contribute to improved serologic tests for leprosy diagnosis/classification and multidrug therapy (MDT) monitoring. This study describes seroreactivity to M. leprae proteins among participants from three highly endemic leprosy areas in Brazil: central-western Goiânia/Goiás (GO) (n = 225), Rondonópolis/Mato Grosso (MT) (n = 764) and northern Prata Village/Pará (PA) (n = 93). ELISA was performed to detect IgG to proteins (92f, 46f, leprosy IDRI diagnostic-1, ML0405, ML1213) and IgM to phenolic glycolipid-I (PGL-I). Multibacillary (MB) leprosy had positive rates for PGL-I that were similar to those for proteins; however, some anti-PGL-I-negative subjects were positive for proteins, suggesting that adding protein antigen to PGL-I can enhance the sensitivity of MB leprosy detection. In MT, different degrees of seroreactivity were observed and ranked for MB, former patients after MDT, paucibacillary (PB) leprosy, household contact (HHC) and endemic control (EC) groups. The seroreactivity of PB patients was low in GO and MT. HHCs from different endemic sites had similar IgG antibody responses to proteins. 46f and 92f were not recognised by most tuberculosis patients, ECs or HHCs within GO, an area with high BCG vaccination coverage. Low positivity in EC and HHC was observed in PA and MT. Our results provide evidence for the development of an improved serologic test that could be widely applicable for MB leprosy testing in Brazil.