@article{101563, keywords = {Mycobacterium leprae, diagnosis, IgM, lateral flow, leprosy, Quantitative UCP-based rapid test, target product profile, Upconverting reporter particle}, author = {Pierneef L and van Hooij A and de Jong D and Wassenaar G and Verhard E and Fat E and Engel N and Khatun M and Soren S and Chowdhury A and van Hees C and Corstjens P and Geluk A}, title = {Rapid test for Mycobacterium leprae infection: a practical tool for leprosy.}, abstract = {
Background: Detection of infection with Mycobacterium leprae allows timely prophylactic treatment, thereby reducing transmission as well as the risk of permanent, leprosy-associated nerve damage. However, since there is no worldwide-implemented standard test for M. leprae infection, detection of infection in asymptomatic individuals remains a major challenge for control programs in endemic areas. In previous studies, we developed and field-tested a lateral flow assay (LFA) quantitatively detecting human IgM against M. leprae-specific phenolic glycolipid I (anti-PGL-I), a marker for both active and past infection. This rapid test utilizes luminescent, background-free, up-converting reporter particles (UCP) and immunochromatography (i.e. the UCP-LF test platform) for accurate quantitation of anti-PGL-I IgM without operator bias. The aim of this study was to evaluate the final version of this quantitative UCP-based rapid test (i.e. PGL-I QURapid), using serum and fingerstick blood (FSB).
Methods: The test comprises a lateral flow strip, in a standard plastic or biodegradable cassette. It can be provided with a humanized, recombinant control to monitor test performance and calculate accurate anti-PGL-I IgM levels. The performance of this QUR-test was assessed using serum and FSB from patients with leprosy (n = 214), tuberculosis (n = 20), buruli ulcer (n = 19), leishmaniasis (n = 14), non-tuberculous mycobacterial (n = 35) infections, as well as healthy Dutch individuals (n = 710) and humanized, recombinant anti-PGL-I IgM antibodies. Plot receiver operating characteristic curves were created and sensitivity (Sn), specificity (Sp) and the area under the curve were calculated to evaluate test performance.
Results: Test results classified multibacillary leprosy patients with 95.0% Sn and 100% Sp using serum and 91.5% Sn and 99.8% Sp using FSB. Qualitative test results could be read after 2 min flow time, with accurate quantitation from 10 min onwards. The new anti-PGL-I IgM control supports production of batches with predetermined seropositivity thresholds and monitoring of the PGL-I QUR-test in various settings.
Conclusion: The operational version of the PGL-I QURapid with point-of-care applicability, meets the WHO target product profile criteria. Thus, this QUR-test is ready for public health implementations.
}, year = {2024}, journal = {Infectious diseases of poverty}, volume = {13}, pages = {88}, month = {12/2024}, issn = {2049-9957}, url = {https://idpjournal.biomedcentral.com/counter/pdf/10.1186/s40249-024-01262-9.pdf}, doi = {10.1186/s40249-024-01262-9}, language = {ENG}, }