qPCR detection of Mycobacterium leprae in biopsies and slit skin smear of different leprosy clinical forms

Autor(es)

Michelle de Campos Soriani Azevedo ; Natália Mortari Ramuno ; Luciana Raquel Vincenzi Fachin ; Mônica Tassa ; Patrícia Sammarco Rosa ; Andrea de Faria Fernandes Belone ; Suzana Madeira Diório ; Cleverson Teixeira Soares ; Gustavo Pompermaier Garlet ; Ana Paula Favaro Trombone

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Infectious Diseases; v. 21, n. 1, p. 71-78, Fev. 2017.
• Citações Web of Science: 5

Resumo

Abstract Leprosy, whose etiological agent is Mycobacterium leprae, is a chronic infectious disease that mainly affects the skin and peripheral nervous system. The diagnosis of leprosy is based on clinical evaluation, whereas histopathological analysis and bacilloscopy are complementary diagnostic tools. Quantitative PCR (qPCR), a current useful tool for diagnosis of infectious diseases, has been used to detect several pathogens including Mycobacterium leprae. The validation of this technique in a robust set of samples comprising the different clinical forms of leprosy is still necessary. Thus, in this study samples from 126 skin biopsies (collected from patients on all clinical forms and reactional states of leprosy) and 25 slit skin smear of leprosy patients were comparatively analyzed by qPCR (performed with primers for the RLEP region of M. leprae DNA) and routine bacilloscopy performed in histological sections or in slit skin smear. Considering clinical diagnostic as the gold standard, 84.9% of the leprosy patients were qPCR positive in skin biopsies, resulting in 84.92% sensitivity, with 84.92 and 61.22% positive (PPV) and negative (NPV) predictive values, respectively. Concerning bacilloscopy of histological sections (BI/H), the sensitivity was 80.15% and the PPV and NPV were 80.15 and 44.44%, respectively. The concordance between qPCR and BI/H was 87.30%. Regarding the slit skin smear, 84% of the samples tested positive in the qPCR. Additionally, qPCR showed 100% specificity, since all samples from different mycobacteria, from healthy individuals, and from other granulomatous diseases presented negative results. In conclusion, the qPCR technique for detection of M. leprae using RLEP primers proved to be specific and sensitive, and qPCR can be used as a complementary test to diagnose leprosy irrespective of the clinical form of disease. (AU)

• Processo FAPESP: 09/06122-5 - Avaliação do papel das células T regulatórias e Th17 na hanseníase humana e experimental: correlações com o espectro imunopatológico das lesões, níveis de expressão de metaloproteases e seus inibidores, e integração com o paradigma Th1/Th2
• Beneficiário: Ana Paula Favaro Trombone Garlet
• Linha de fomento: Auxílio à Pesquisa - Apoio a Jovens Pesquisadores
• Processo FAPESP: 11/09218-3 - Quantificação do Mycobacterium leprae em lesões cutâneas de pacientes com hanseníase e em amostras de coxim plantar de camundongos infectados.
• Beneficiário: Michelle de Campos Soriani Azevedo
• Linha de fomento: Bolsas no Brasil - Programa Capacitação - Treinamento Técnico