Utility of immunoglobulin isotypes against LID-1 and NDO-LID for, particularly IgG1, confirming the diagnosis of multibacillary leprosy

BACKGROUND Leprosy remains a health problem in many countries, with difficulties in diagnosis resulting in delayed treatment and more severe disabilities. Antibodies against several Mycobacterium leprae antigens have, however, shown value as diagnostic and/or prognostic markers. OBJECTIVES The objective of this study was to evaluate serum immunoglobulin (Ig) IgM and IgG subclass reactivity against three M. leprae specific antigens: NDO-HSA, a conjugate formed by natural octyl disaccharide bound to human serum albumin; LID-1, the fusion protein product of the ml0405 and ml2331 genes; and NDO-LID, a combination of LID-1 and NDO. METHODS Sera from healthy controls, paucibacillary (PB) and multibacillary (MB) leprosy patients, and their respective household contacts, were evaluated for the presence of antigen-specific IgM, IgG, and IgG subclass antibodies by enzyme-linked immunosorbent assay (ELISA). The sensitivity and specificity of each ELISA were evaluated by receiver operating characteristic (ROC) curve analysis. FINDINGS Our data confirm that serum IgM antibodies against NDO-HSA and IgG antibodies against LID-1, as well as IgG/M antibodies against NDO-LID, are markedly increased in MB patients. For the first time, our data reveal a selective increase in IgG1 and IgG3 antibodies against LID-1 and NDO-LID in MB patients, demonstrating that these antibody isotypes are suitable for differentiation between MB and PB patients. ROC curve analysis indicates an improved capacity for diagnosing MB leprosy patients using the detection of IgG antibodies, particularly the IgG1 isotype, specific to LID-1 and NDO-LID over the performance levels attained with NDO-HSA. CONCLUSIONS Our findings indicate that serological tests based on the detection of antigen-specific IgG1 antibodies are a useful tool to differentiate MB from PB patients, and indicate the enhanced performance of the LID-1 and NDO-LID antigens in the serodiagnosis of leprosy.

Multibacillary leprosy patients with high and persistent serum antibodies to leprosy IDRI diagnostic-1/LID-1: higher susceptibility to develop type 2 reactions

Leprosy inflammatory episodes [type 1 (T1R) and type 2 (T2R) reactions] represent the major cause of irreversible nerve damage. Leprosy serology is known to be influenced by the patient’s bacterial index (BI) with higher positivity in multibacillary patients (MB) and specific multidrug therapy (MDT) reduces antibody production. This study evaluated by ELISA antibody responses to leprosy Infectious Disease Research Institute diagnostic-1 (LID-1) fusion protein and phenolic glycolipid I (PGL-I) in 100 paired serum samples of 50 MB patients collected in the presence/absence of reactions and in nonreactional patients before/after MDT. Patients who presented T2R had a median BI of 3+, while MB patients with T1R and nonreactional patients had median BI of 2.5+ (p > 0.05). Anti-LID-1 and anti-PGL-I antibodies declined in patients diagnosed during T1R (p < 0.05). Anti-LID-1 levels waned in MB with T2R at diagnosis and nonreactional MB patients (p < 0.05). Higher anti-LID-1 levels were seen in patients with T2R at diagnosis (vs. patients with T1R at diagnosis, p = 0.008; vs. nonreactional patients, p = 0.020) and in patients with T2R during MDT (vs. nonreactional MB, p = 0.020). In MB patients, high and persistent anti-LID-1 antibody levels might be a useful tool for clinicians to predict which patients are more susceptible to develop leprosy T2R.

Análise comparativa da reatividade anti-LID-1, NDO-LID, NDO-HSA e PGL-1 em hanseníase / Comparative analysis of the reactivity anti-LID-1, NDO-LID, NDO-HSA and PGL-1 in leprosy

A infecção subclínica pode ser avaliada por meio de teste sorológico, que determina imunoglobulinas circulantes. O objetivo do presente estudo foi analisar a reatividade de diferentes antígenos em casos novos de hanseníase, contatos domiciliares de casos e em população de área endêmica, com o intuito de identificar o melhor antígeno para o diagnóstico sorológico da hanseníase e detecção de indivíduos infectados pelo Mycobacterium leprae.Trata-se de um estudo transversal de natureza exploratória e analítica. A reatividade anti-LID-1, NDO-LID, NDO-HSA e PGL-1 foi avaliada por meio do enzyme-linked immunosorbentassay. Foram analisadas amostras de sangue total em papel de filtro Whatman de 2494indivíduos da população de sete municípios da microrregião de Almenara e de soro de 94casos novos de hanseníase e 104 contatos domiciliares de casos residentes no município de Uberlândia. O Banco de Dados foi criado no Software Epi Info versão 3.5.1 e análise realizada no software Statistical Package for the Social Sciences for Windows 18 e no GraphPad Prism versão 5. Para análise estatística foram utilizados os seguintes testes: Kolmogorov-Smirnov, Kruskal-Wallis one-way (H), Mann-Whitney (U) com correção de Bonferroni, kappa, Spearman (rho), teste Qui-quadrado de Pearson e regressão logística binária. Foi observado maior soropositividade no grupo de casos multibacilares (MB), em contatos domiciliares de casos MB e nos indivíduos residentes nos municípios de Almenara e Jequitinhonha. Obteve-se correlação positiva entre a sorologia e o índice baciloscópico,concordância substancial e significativa no grupo de casos novos de hanseníase e correlação positiva para todos os antígenos testados. Os testes anti-LID-1 e anti-NDO-LID apresentaram melhor performance para identificar os contatos domiciliares e ou indivíduos da população...

The subclinical infection can be evaluated by serologic test which determine circulating immunoglobulins. The aim of this study was to analyze the reactivity of different antigens inleprosy cases, household contacts of index cases and the population of the endemic area toidentify the best antigen for the diagnosis of leprosy and detection of individuals infected with Mycobacterium leprae. It is a cross-sectional study of exploratory and analytical nature. There activity anti-LID-1, NDO-LID, NDO-HAS e PGL-1 were evaluated using the enzyme linke dimmunosorbent assay. The whole blood in What man filter paper of 2494 individuals from the general population of seven municipalities in the micro-Almenara and serum of 94 patients with leprosy and 104 household contacts of patients residing in Uberlândia were analyzed. The database was created in Epi Info software version 3.5.1 and analysis in the software Statistical Package for Social Sciences for Windows 18 and GraphPad Prism version5. For statistical analysis the following tests were used: Kolmogorov-Smirnov, Kruskal Wallisone-way (H), Mann-Whitney (U) with Bonferroni correction, kappa, Spearman (rho), chisquaretest of Pearson and binary logistic regression. Identied higher seropositivity in the group of MB patients, household contacts of MB patients and in individuals living in the municipalities of Almenara and Jequitinhonha. Observed positive correlation between serology test and bacterial index, substantial agreement and significant in patients positive and positive correlation for all antigens. The LID-1 and NDO-LID antigens showed greater ability to identify household contacts or the general population infected with M. leprae, but the performance of the NDO-LID was better. The native PGL-1 had higher seropositivity than the NDO-HSA for all clinical forms of leprosy and household contacts. The seropositivity prevalence in the general population was higher than the detection rate of leprosy...