British Leprosy Relief Association
Comparison of three immunological tests for leprosy diagnosis and detection of subclinical infection
De Melo ReisÉricaa
aUniversidade Federal de Uberlândia – Centro de Referência Nacional em Hanseníase Av. Aspirante Mega, 77 – Bairro Jaraguá, 38413-018 – Uberlândia, MG, Brazil
bMycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, 1682 Campus Delivery, Fort Collins, CO 80523, USA
cDept. Medical Microbiology & Immunology, Genome & Biomedical Sciences Facility, GBSF Suite 5503, room 5521, University of California – Davis, Davis, CA, 95616, USA
Correspondence to: Luiz Ricardo Goulart, PhD – Professor, Dept. Medical Microbiology & Immunology, Genome & Biomedical Sciences Faculty, GBSF Suite 5503, Room 5521, University of California – Davis, Davis, CA 95616, U.S.A. (Tel: +1 530 752 8113; Fax: +1 530 754 7240; e-mail: firstname.lastname@example.org)
L.R.G and I.M.B.G are Senior Co-authors.
Our aim was to compare the performance of three serological assays in leprosy patients and their household contacts utilising two quantitative ELISA tests using native PGL-I (PGL-1 ELISA), synthetic ND-O-HSA (ND-O-HSA ELISA), and the semi-quantitative lateral flow test (ML Flow).
Comparisons among three immunological assays, PGL-I ELISA, ND-O- HSA ELISA, and ML Flow were performed in 154 leprosy patients, 191 household contacts and 52 health subjects.
The sensitivity results of the PGL-1, ND-O-HSA, and ML Flow were 68.83%, 63.84%, and 60.65%, respectively, with specificity of 98% for both ELISA assays. The native and synthetic PGL-I ELISA assays detected antibodies in 22.73% and 31.82% of the paucibacillary (PB) patients, respectively and the ML Flow test did not detect antibodies in this group. The ML Flow test was able to discriminate patients into PB or multibacillary (MB) forms, while the native PGL-I and ND-O- HSA was correlated with the bacillary load and the Ridley-Jopling clinical forms. In household contacts, the native PGL-I, ND-O-HSA, and ML Flow assays detected seropositivity of 25%, 17%, and 10%, respectively.
The use of ELISA and ML Flow tests are thus recommended as additional tools in the diagnosis and classification of the clinical forms, aiding in prescribing the correct treatment regimen to prevent subsequent nerve damage and disability, and besides, the PGL-I ELISA may be used to detect subclinical infection in leprosy.