Performance of serological tests PGL1 and NDO-LID in the diagnosis of leprosy in a reference Center in Brazil

Abstract

BackgroundEarly detection of leprosy and multidrug therapy are crucial to achieve zero transmission and zero grade II incapacities goals of World Health Organization. Leprosy is difficult to diagnose because clinical forms vary and there are no gold standard methods to guide clinicians. The serological rapid tests aid the clinical diagnosis and are available for field use. They are easy to perform, do not require special equipment or refrigeration and are cheaper than the molecular tests.MethodsWe evaluated the performance of two rapid serological tests (PGL1 and NDO-LID) in the discrimination of leprosy cases from healthy individuals at the Alfredo da Matta Foundation, a reference center for the disease in Manaus, Amazonas, Brazil. PGL1 and NDO-LID rapid tests are capable of detecting specific antibodies of M. leprae, IgM and IgM/IgG, respectively. A total of 530 healthy subjects and 171 patients (50 with paucibacillary and 121 multibacillary leprosy) were included in the study.ResultsAmong the paucibacillary leprosy patients, the sensitivity was 34.0 and 32.0% for the NDO-LID and PGL1, respectively. In multibacillary leprosy patients, the NDO-LID sensitivity was 73.6% and the PGL1 was 81.0%. Serological tests demonstrated specificities of 75.9% for PGL-1 and 81.7% for NDO-LID. The positive predictive value (PPV), negative predictive value (NPV) and accuracy in multibacillary patients were 47.9, 93.1, and 80.2% respectively for the NDO-LID, and 43.4, 94.6 76.8% for PGL1.ConclusionsThe tests showed limited capacity in the diagnosis of the disease, however, the high negative predictive value of the tests indicates a greater chance of true negatives in this group favoring exclusion of leprosy. This characteristic of the ML flow test is important in aiding clinical Diagnosis, especially in a region endemic to the disease and with other confounding skin conditions.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3653-0) contains supplementary material, which is available to authorized users.

Application of new host biomarker profiles in quantitative point-of-care tests facilitates leprosy diagnosis in the field

“…Therefore, elaborate host immune profiling of HC stratified by M.leprae DNA presence in nasal swabs or slit skin slides may aid in identifying biomarkers associated with M.leprae exposure or infection without clinical symptoms. αPGL-I IgM levels have been measured in HC in order to predict the development of leprosy disease, but has so far proven insufficient for early detection of leprosy or onset of disease [32,33]. Longitudinal monitoring of the host biomarkers described in this study can provide more insight into the predictive capacity of this biomarker signature.…”

Recombinant polypeptide of Mycobacterium leprae as a potential tool for serological detection of leprosy

“…The detection rates among available commercial tests vary widely depending on patient populations, as well as disease spectrum, with lower rates in PB leprosy patients (van Hooij et al 2017). The detection rates found in a study that used proteins like NDO-LID-1 and PGL-1 were 34% and 32% in PB patients versus 73.6% and 81% in MB individuals, respectively (Leturiondo et al 2019). Although this test was able to exhibit better detection capabilities than standard tests using PGL-I and LID-I, monitoring of individuals in the early stages of the disease and/or PB patients remains a challenge (Frade et al 2017).…”

“…The use of high-affinity HLA-binding linear epitopes in the construction of rMLP15 may aid in detecting both MB and PB leprosy patients. Available commercial tests like PGL-I or LID-1 protein-based tests can detect MB patients with high bacillary loads, but fail to detect PB leprosy patients, delegating them to a supportive test for treatment direction but not useful to detect early stages of the disease (Spencer et al 2011; Geluk et al 2011; van Hooij et al 2017; Duthie et al 2007; Leturiondo et al 2019). PB leprosy, unlike MB leprosy, displays a dominant cellular phenotype with restricted anti- M. leprae antibody production.…”

Extensor plaques with associated arthritis and neuropathy

“…Paucibacillary cases mount an effective cellular immune response to control bacterial replication, which mitigates antibody responses. 4 , 5 PCR – Correct. Identification of M leprae is possible by using PCR, and this technique can be applied to skin biopsy samples, skin smears, nerves, urine, oral or nasal swabs, and blood.…”

“…Paucibacillary cases mount an effective cellular immune response to control bacterial replication, which mitigates antibody responses. 4 , 5 …”