title: Comparison of two different PCR amplification products (the 18-kDa protein gene vs. RLEP repetitive sequence) in the diagnosis of Mycobacterium leprae.
abstract: To determine the best molecular method for diagnosing leprosy, two sets of Mycobacterium leprae-specific primers were compared. Fresh biopsies and slit skin smear samples were obtained from 67 leprosy patients and examined by touchdown (TD) PCR using primers amplifying either a 129-bp fragment of the RLEP repetitive sequence or a 360-bp fragment of the 18-kDa protein gene of M. leprae. Seventeen of 30 (56.7%) biopsy specimens and four of 37 (10.8%) slit skin smear specimens were positive using the primer for the 18-kDa protein gene, whereas 24 of 30 (80%) biopsy and 27 of 37 (73%) slit skin smear samples showed detectable PCR products in the RLEP repetitive sequence. Twenty-one of 31 cases (67.7%) with a bacterial index of zero were PCR positive for the primer RLEP repetitive sequence. These results demonstrate that detection of M. leprae using PCR with primers to a RLEP sequence is more sensitive and specific than PCR with the 18-kDa protein gene primers and also slit smears with acid fast staining. PCR of RLEP repetitive sequences is therefore a useful means of detecting M. leprae DNA even when it is present at very low levels.
authors.affiliation: Institute of Hansen's Disease, Department of Pathology, The Catholic University of Korea, Seoul and The Affiliated Hospital, Korean Hansen Welfare Association, Euiwang City, Korea.
authors.forename: T-J
authors.initials: TJ
authors.lastname: Kang
authors.forename: S-K
authors.initials: SK
authors.lastname: Kim
authors.forename: S-B
authors.initials: SB
authors.lastname: Lee
authors.forename: G-T
authors.initials: GT
authors.lastname: Chae
authors.forename: J-P
authors.initials: JP
authors.lastname: Kim
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000235:genetics*; D017931:DNA Primers; D006801:Humans; D007918:Leprosy / Q000175:diagnosis* / Q000382:microbiology; D009166:Mycobacterium leprae / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods*; D012091:Repetitive Sequences, Nucleic Acid; D012867:Skin / Q000382:microbiology
chemical_list: C067864:18 kDa protein, Mycobacterium leprae; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D017931:DNA Primers