Emerith Mayra Hungria

Seroreactivity to new Mycobacterium leprae protein antigens in different leprosy-endemic regions in Brazil

New Mycobacterium leprae protein antigens can contribute to improved serologic tests for leprosy diagnosis/classification and multidrug therapy (MDT) monitoring. This study describes seroreactivity to M. leprae proteins among participants from three highly endemic leprosy areas in Brazil: central-western Goiânia/Goiás (GO) (n = 225), Rondonópolis/Mato Grosso (MT) (n = 764) and northern Prata Village/Pará (PA) (n = 93). ELISA was performed to detect IgG to proteins (92f, 46f, leprosy IDRI diagnostic-1, ML0405, ML1213) and IgM to phenolic glycolipid-I (PGL-I). Multibacillary (MB) leprosy had positive rates for PGL-I that were similar to those for proteins; however, some anti-PGL-I-negative subjects were positive for proteins, suggesting that adding protein antigen to PGL-I can enhance the sensitivity of MB leprosy detection. In MT, different degrees of seroreactivity were observed and ranked for MB, former patients after MDT, paucibacillary (PB) leprosy, household contact (HHC) and endemic control (EC) groups. The seroreactivity of PB patients was low in GO and MT. HHCs from different endemic sites had similar IgG antibody responses to proteins. 46f and 92f were not recognised by most tuberculosis patients, ECs or HHCs within GO, an area with high BCG vaccination coverage. Low positivity in EC and HHC was observed in PA and MT. Our results provide evidence for the development of an improved serologic test that could be widely applicable for MB leprosy testing in Brazil.

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 patients 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.

Alterations to antigen-specific immune responses before and after multidrug therapy of leprosy.

This study evaluated the impact of leprosy multidrug therapy (MDT) on cell-mediated immunity (CMI) and antibody responses at diagnosis in untreated paucibacillary (PB) (n=15) and multibacillary (MB) patients (n=15) using a panel of Mycobacterium leprae recombinant antigens (rMLs) (CMI: 46f, ML0276, ML2055, leprosy IDRI diagnostic 1 [LID-1], and ML2629, as negative control; serology: LID-1, 46f, 92f, and 33f, as negative control, and phenolic glycolipid I [PGL-I]) and at 2 time points after MDT (PB: 8-20months; MB: 4-22months). At diagnosis, PB patients produced interferon gamma (IFNγ), and MB patients exhibited low/absent response. Shortly after MDT, IFNγ production in PB patients declined except for LID-1; MB patients produced IFNγ to LID-1. Almost 2years after MDT, IFNγ levels declined in PB and MB patients. Most untreated PB patients were seronegative to PGL-I and rML, remaining so after MDT. Most untreated MB patients were seropositive to all antigens, and IgG to rMLs declined after MDT. Reduction in antigen-specific CMI in PB and in antibody response in MB patients may help monitor MDT effectiveness.

Whole genome sequencing distinguishes between relapse and reinfection in recurrent leprosy cases

Background Since leprosy is both treated and controlled by multidrug therapy (MDT) it is important to monitor recurrent cases for drug resistance and to distinguish between relapse and reinfection as a means of assessing therapeutic efficacy. All three objectives can be reached with single nucleotide resolution using next generation sequencing and bioinformatics analysis of Mycobacterium leprae DNA present in human skin. Methodology DNA was isolated by means of optimized extraction and enrichment methods from samples from three recurrent cases in leprosy patients participating in an open-label, randomized, controlled clinical trial of uniform MDT in Brazil (U-MDT/CT-BR). Genome-wide sequencing of M. leprae was performed and the resultant sequence assemblies analyzed in silico. Principal findings In all three cases, no mutations responsible for resistance to rifampicin, dapsone and ofloxacin were found, thus eliminating drug resistance as a possible cause of disease recurrence. However, sequence differences were detected between the strains from the first and second disease episodes in all three patients. In one case, clear evidence was obtained for reinfection with an unrelated strain whereas in the other two cases, relapse appeared more probable. Conclusions/Significance This is the first report of using M. leprae whole genome sequencing to reveal that treated and cured leprosy patients who remain in endemic areas can be reinfected by another strain. Next generation sequencing can be applied reliably to M. leprae DNA extracted from biopsies to discriminate between cases of relapse and reinfection, thereby providing a powerful tool for evaluating different outcomes of therapeutic regimens and for following disease transmission.

Application of Mycobacterium Leprae-specific cellular and serological tests for the differential diagnosis of leprosy from confounding dermatoses

Mycobacterium leprae-specific serological and cell-mediated-immunity/CMI test were evaluated for the differential diagnosis of multibacillary/MB, and paucibacillary/PB leprosy from other dermatoses. Whole-blood assay/WBA/IFNγ stimulated with LID-1 antigen and ELISA tests for IgG to LID-1 and IgM to PGL-I were performed. WBA/LID-1/IFNγ production was observed in 72% PB, 11% MB leprosy, 38% dermatoses, 40% healthy endemic controls/EC. The receiver operating curve/ROC for WBA/LID-1 in PB versus other dermatoses showed 72.5% sensitivity, 61.5% specificity and an area-under-the-curve/AUC=0.75; 74% positive predictive value/PPV, 59% negative predictive value/NPV. Anti PGL-I serology was positive in 67% MB, 8% PB leprosy, 6% of other dermatoses; its sensitivity for MB=66%, specificity=93%, AUC=0.89; PPV=91%, NPV=72%. Anti-LID-1 serology was positive in 87% MB, 7% PB leprosy, all other participants were seronegative; 87.5% sensitivity for MB, 100% specificity, AUC=0.97; PPV=100%, NPV=88%. In highly endemic areas anti-LID-1/PGL-I serology and WBA/LID-1-represent useful tools for the differential diagnosis of leprosy from other confounding dermatoses.

Antigen-specific secretion of IFNγ and CXCL10 in whole blood assay detects Mycobacterium leprae infection but does not discriminate asymptomatic infection from symptomatic leprosy

To advance toward a whole blood assay (WBA)-based test capable of facilitating the diagnosis of paucibacillary (PB) leprosy, we evaluated a prototype in-tube WBA using combinations of Mycobacterium leprae antigens. Blood was collected from newly diagnosed untreated PB (n=38), multibacillary (MB) (n=30), healthy household contacts (HHC) of MB (n=27), and endemic controls (n=61) residing in Goiânia and Fortaleza, Brazil. Blood was incubated with M. leprae cell sonicate, recombinant proteins (46f+LID-1; ML0276+LID-1), or controls (phosphate-buffered saline, phytohemagglutinin, M. tuberculosis purified protein derivative). Antigen-specific IFNγ production was observed in 71-84% and 55% of PB and HHC, respectively. Antigen-specific CXCL10 levels were similarly assessed to determine if, unlike IFNγ, CXCL10 could differentiate PB from HHC with repeated exposure/asymptomatic M. leprae infection. The CXCL10 levels induced in response to M. leprae antigens could not, however, differentiate PB from HHC. Despite these limitations, the WBAs reported here still represent important tools for assessing M. leprae infection rates and evaluating the impact of control measures.

In situ T regulatory cells and Th17 cytokines in paired samples of leprosy type 1 and type 2 reactions

Leprosy is a complex chronic, infectious dermato-neurological disease that affects the skin and peripheral nerves especially during immuno-inflammatory episodes known as type 1/T1R and type 2/T2R reactions. This study investigated the in situ expression of CD25+Foxp3+ Treg cells and TGF-β1, IFN-γ, IL-17 in leprosy T1R and T2R. Tregs were evaluated in 114 skin biopsies from 74 leprosy patients: 56 T1R (28-paired reaction-free/reactional biopsies, 28 unpaired T1R), 18 T2R (12 paired reaction-free/reactional biopsies, 6 unpaired T2R). Double CD25+Foxp3+immunostained Treg cells obtained by automated platform (Ventana BenchMark XT, Roche, Mannheim, Germany) were counted (Nikon Eclipse E400 2mm2). Cytokine expression was evaluated by immunostaining in 96 biopsies (48 paired reaction-free/reactional lesions, 24 T1R, 24 T2R) using rabbit polyclonal anti human TGF-β1, IFN-γ, IL-17 antibodies (Santa Cruz Biotechnology CA, USA). Treg cell counts in leprosy reactional lesions were higher compared to reaction-free (p = 0.002). Treg numbers were higher in T1R compared to paired unreactional T1R lesions (p = 0.001). Similar frequency of Treg was seen in paired reactional versus unreactional T2R lesions. Higher expression of TGF-β, IFN-γ and IL-17 was seen in T2R lesions compared to T1R and reaction-free lesions. The increase in Treg cells during T1R suggests a suppressive role to control the exacerbated cellular immune response during T1R that can cause tissue and nerve damage. Evidences of upregulated Treg cells in TR1, which usually occurs in patients with Th1-Th17 immunity and the indications of the expression of Th17/IL-17 in T2R, which develops in patients with Th2-Treg profile, suggest plasticity of Treg-Th17 cells populations and a potential role for these cell populations in the immunopathogenesis of leprosy reactions.

Mycobacterium leprae-Specific Antibodies in Multibacillary Leprosy Patients Decrease During and After Treatment With Either the Regular 12 Doses Multidrug Therapy (MDT) or the Uniform 6 Doses MDT

Leprosy serology reflects the bacillary load of patients and multidrug therapy (MDT) reduces Mycobacterium leprae-specific antibody titers of multibacillary (MB) patients. The Clinical Trial for Uniform Multidrug Therapy Regimen for Leprosy Patients in Brazil (U-MDT/CT-BR) compared outcomes of regular 12 doses MDT/R-MDT and the uniform 6 doses MDT/U-MDT for MB leprosy, both of regimens including rifampicin, clofazimine, and dapsone. This study investigated the impact of R-MDT and U-MDT and the kinetic of antibody responses to M. leprae-specific antigens in MB patients from the U-MDT/CT-BR. We tested 3,400 serum samples from 263 MB patients (R-MDT:121; U-MDT:142) recruited at two Brazilian reference centers (Dona Libânia, Fortaleza, Ceará; Alfredo da Matta Foundation, Manaus, Amazonas). Enzyme-linked immunosorbent assays with three M. leprae antigens [NT-P-BSA: trisaccharide-phenyl of phenollic glycolipid-I antigen (PGL-I); LID-1: Leprosy Infectious Disease Research Institute Diagnostic 1 di-fusion recombinant protein; and ND-O-LID: fusion complex of disaccharide-octyl of PGL-I and LID-1] were performed using around 13 samples per patient. Samples were collected at baseline/M0, during MDT (R-MDT:M1–M12 months, U-MDT:M1–M6 months) and after MDT discontinuation (first, second year). Statistical significance was assessed by the Mann–Whitney U test for comparison between groups (p values < 0.05). Mixed effect multilevel regression analyses were used to investigate intraindividual serological changes overtime. In R-MDT and U-MDT groups, males predominated, median age was 41 and 40.5 years, most patients were borderline lepromatous and lepromatous leprosy (R-MDT:88%, U-MDT: 90%). The bacilloscopic index at diagnosis was similar (medians: 3.6 in the R-MDT and 3.8 in the U-MDT group). In R-MDT and U-MDT groups, a significant decline in anti-PGL-I positivity was observed from M0 to M5 (p = 0.035, p = 0.04, respectively), from M6 to M12 and at the first and second year posttreatment (p < 0.05). Anti-LID-1 antibodies declined from M0 to M6 (p = 0.024), M7 to M12 in the R-MDT; from M0 to M4 (p = 0.003), M5 to M12 in the U-MDT and posttreatment in both groups (p > 0.0001). Anti-ND-O-LID antibodies decreased during and after treatment in both groups, similarly to anti-PGL-I antibodies. Intraindividual serology results in R-MDT and U-MDT patients showed that the difference in serology decay to all three antigens was dependent upon time only. Our serology findings in MB leprosy show that regardless of the duration of the U-MDT and R-MDT, both of them reduce M. leprae-specific antibodies during and after treatment. In leprosy, antibody levels are considered a surrogate marker of the bacillary load; therefore, our serological results suggest that shorter U-MDT is also effective in reducing the patients’ bacillary burden similarly to R-MDT. Clinical Trial Registration ClinicalTrials.gov, NCT00669643.