Serological evidence of Toxoplasma gondii infection as potential risk for the development of lepromatous leprosy in an endemic area for both neglected tropical diseases in Brazil.

BACKGROUND: Mycobacterium leprae and Toxoplasma gondii infections are both neglected tropical diseases highly prevalent in Brazil. Infection with certain parasite species can significantly alter susceptibility to other important pathogens, and/or influence the development of pathology. Here we investigated the possible influence of M. leprae/T. gondii co-parasitism on the manifestation of leprosy and its clinical forms. METHODS: Participants (n = 291) were recruited in Campos dos Goytacazes city, Rio de Janeiro state, southeast Brazil, from August 2015 to December 2019 and clinically diagnosed for leprosy. Participants were selected based on the presence (patients) or absence (healthy controls) of the leprosy disease. Contacts of patients were also recruited for this study. Serum samples from patients (n = 199) with leprosy, contacts (n = 40) and healthy controls (n = 52) were investigated for levels of IgM and IgG anti-phenolic glycolipid-1 (PGL-1) by ELISA. Additionally, IgG antibody against soluble Toxoplasma antigen (STAg) was measured in sera samples from leprosy patients, contacts and healthy controls for Toxoplasma gondii serology by ELISA. Anti-PGL-1 IgG and IgM levels were compared using one-way ANOVA Kruskal-Wallis or Mann-Whitney, while Spearman test was used to correlate levels of IgG anti-STAg and IgM/IgG anti-PGL-1 from seropositive and seronegative individuals for T. gondii infection. The risk of T. gondii infection for leprosy disease was assessed using Fisher's test. RESULTS: Levels of IgM anti-PGL-1 antibodies were significantly higher in multibacillary (MB) patients compared to paucibacillary (PB) patients (P = 0.0068). Higher IgM and IgG levels anti-PGL-1 were detected in patients with the lepromatous forms. The serologic prevalence for T. gondii infection was 74.9%. We detected increased anti-STAg antibody levels in leprosy patients (79.4%), reaching 88.8% within those with lepromatous form of this disease. The leprosy risk increase in T. gondii seropositive individuals was two-fold (odds ratio [OR] = 2.055; 95% confidence intervals [95% CI]: 1.18-3.51) higher than those seronegative, and considering the lepromatous leprosy risk this increase was even dramatic (OR = 4.33; 95% CI: 1.76-9.69) in T. gondii seropositive individuals. Moreover the leprosy risk in T. gondii seropositive individuals was weakly correlated to the levels of IgG anti-STAg and IgM/IgG anti-PGL-1. CONCLUSIONS: Altogether, our results suggest that T. gondii infection may exert immunomodulatory properties that influence to the susceptibility of leprosy, mainly on its more severe clinical form. A better understanding of parasite immunomodulation can ultimately contribute to the development of medical applications.

Immunological biomarkers of subclinical infection in household contacts of leprosy patients.

Hansen's disease (or leprosy) still persists as a serious public health issue. Its diagnosis is based primarily on the detection of clinical signs that are characteristic of the disease. Studies have pointed to the selection of a set of serological and cellular biomarkers of subclinical infection that result in an efficient diagnosis. The aim of this study was compare index cases and their household contacts to identify differentially expressed biomarkers of immune response in leprosy that could provide reliable evidence of subclinical infection in household contacts. The study population consisted of index cases with multibacillary form (IC, n = 13) and their household contacts (HC, n = 14). Serum cytokines and chemokines were quantified using the cytometric beads array (CBA) system. The humoral response was assessed by ELISA test. Flow cytometry was used to characterize the cellular immune response. Monocyte and CD4 + T lymphocytes frequency was significantly higher in IC. Both CD4+ and CD8 + T lymphocytes had a reduced CD25 expression in HC. The immunoglobulin (Ig)M profile anti- NDO-HSA, LID-1, and NDOLID antigens was significantly higher in IC. This study points to the monocyte and CD4+ lymphocyte frequency, as well as specific IgM profile, as predictors of subclinical infection in the household contacts.

Differential immunoglobulin and complement levels in leprosy prior to development of reversal reaction and erythema nodosum leprosum.

BACKGROUND: Leprosy is a treatable infectious disease caused by Mycobacterium leprae. However, there is additional morbidity from leprosy-associated pathologic immune reactions, reversal reaction (RR) and erythema nodosum leprosum (ENL), which occur in 1 in 3 people with leprosy, even with effective treatment of M. leprae. There is currently no predictive marker in use to indicate which people with leprosy will develop these debilitating immune reactions. Our peripheral blood mononuclear cell (PBMC) transcriptome analysis revealed that activation of the classical complement pathway is common to both RR and ENL. Additionally, differential expression of immunoglobulin receptors and B cell receptors during RR and ENL support a role for the antibody-mediated immune response during both RR and ENL. In this study, we investigated B-cell immunophenotypes, total and M. leprae-specific antibodies, and complement levels in leprosy patients with and without RR or ENL. The objective was to determine the role of these immune mediators in pathogenesis and assess their potential as biomarkers of risk for immune reactions in people with leprosy. METHODOLOGY/FINDINGS: We followed newly diagnosed leprosy cases (n = 96) for two years for development of RR or ENL. They were compared with active RR (n = 35), active ENL (n = 29), and healthy household contacts (n = 14). People with leprosy who subsequently developed ENL had increased IgM, IgG1, and C3d-associated immune complexes with decreased complement 4 (C4) at leprosy diagnosis. People who developed RR also had decreased C4 at leprosy diagnosis. Additionally, elevated anti-M. leprae antibody levels were associated with subsequent RR or ENL. CONCLUSIONS: Differential co-receptor expression and immunoglobulin levels before and during immune reactions intimate a central role for humoral immunity in RR and ENL. Decreased C4 and elevated anti-M. leprae antibodies in people with new diagnosis of leprosy may be risk factors for subsequent development of leprosy immune reactions.

Anti-Lipoarabinomannan-Specific Salivary IgA as Prognostic Marker for Leprosy Reactions in Patients and Cellular Immunity in Contacts.

Leprosy causes the most common peripheral neuropathy of infectious etiology, posing an important public health problem worldwide. Understanding the molecular and immunological mechanisms of nerve damage induced by M. leprae is mandatory to develop tools for early diagnosis and preventive measures. The phenolic glycolipid 1 (PGL-1) and lipoarabinomannan (LAM) antigens are major components of the bacterial surface and are implicated on leprosy immunopathogenesis and neural damage. Although the anti-PGL-1 serum IgM is highly used for operational classification of patients, the anti-LAM salivary IgA (sIgA) has not been investigated as diagnostic or prognostic marker in leprosy. Our aim was to assess the presence of anti-LAM sIgA in leprosy patients and their contacts in order to demonstrate whether such expression was associated with leprosy reactions. Distinct patterns of anti-LAM slgA were observed among groups, which were stratified into treatment-naïve patients (116), patients who completed multidrug therapy-MDT (39), household contacts (111), and endemic controls (11). Both anti-LAM sIgA and anti-PGL-I serum IgM presented similar prognostic odds toward leprosy reactions [(odds ratio) OR = 2.33 and 2.78, respectively]. Furthermore, the anti-LAM sIgA was highly correlated with multibacillary (MB) forms (OR = 4.15). Contrarily, among contacts the positive anti-LAM sIgA was highly correlated with those with positive Mitsuda test, suggesting that the presence of anti-LAM slgA may act as an indicator of cellular immunity conferred to contacts. Our data suggest that anti-LAM slgA may be used as a tool to monitor patients undergoing treatment to predict reactional episodes and may also be used in contacts to evaluate their cellular immunity without the need of Mitsuda tests.

Comparison of Enzyme-Linked Immunosorbent Assay Using Either Natural Octyl Disaccharide-Leprosy IDRI Diagnostic or Phenolic Glycolipid-I Antigens for the Detection of Leprosy Patients in Colombia.

Leprosy is a chronic infectious disease with a broad spectrum of manifestations. Delays in attaining correct diagnosis permit progressive peripheral nerve damage that can produce irreversible disabilities. Tests detecting antigen-specific antibodies can aid the diagnostic process and potentially detect patients earlier. Reported tests have lacked optimal sensitivity and specificity; however, the need to develop new tests to aid early diagnosis still remains. In this study, we determined the sensitivity, specificity, positive predictive value, and negative predictive value of enzyme-linked immunosorbent assay (ELISA) using natural octyl disaccharide-leprosy IDRI diagnostic (NDO-LID). Serum samples from confirmed multibacillary patients (N = 338) and paucibacillary patients (N = 58) were evaluated and contrasted against samples from individuals without leprosy (100 healthy persons, 36 leishmaniasis or tuberculosis patients). ELISA detecting either antigen-specific IgM, IgG, or the combination of IgG and IgM (with protein A) were conducted. At a sensitivity of 78% among all patients, serum IgM antibodies against the NDO-LID conjugate were detected at a greater level than those recognizing phenolic glycolipid-I antigen (64% overall sensitivity), while providing similar specificity (97% versus 100%, respectively). Given the inclusion of the LID-1 protein within NDO-LID, we also detected conjugate-specific IgG within patient sera at a sensitivity of 81.6%. The use of protein A to simultaneously detect both antigen-specific IgG and IgM isotypes yielded the highest overall sensitivity of 86.3%. Taken together, our data indicate that the detection of both IgG and IgM antibodies against NDO-LID with protein A provided the best overall ability to detect Colombian leprosy patients.

Can baseline ML Flow test results predict leprosy reactions? An investigation in a cohort of patients enrolled in the uniform multidrug therapy clinical trial for leprosy patients in Brazil.

BACKGROUND: The predictive value of the serology to detection of IgM against the Mycobacterium leprae-derived phenolic glycolipid-I/PGL-I to identify leprosy patients who are at higher risk of developing reactions remains controversial. Whether baseline results of the ML Flow test can predict leprosy reactions was investigated among a cohort of patients enrolled in The Clinical Trial for Uniform Multidrug Therapy for Leprosy Patients in Brazil (U-MDT/CT-BR). METHODS: This was a descriptive study focusing on the main clinical manifestations of leprosy patients enrolled in the U-MDT/CT-BR from March 2007 to February 2012 at two Brazilian leprosy reference centers. For research purposes, 753 leprosy patients were categorized according to a modified Ridley-Jopling (R&J) classification and according to the development of leprosy reactions (reversal reaction/RR and erythema nodosum leprosum/ENL), and whether they had a positive or negative bacillary index/BI. RESULTS: More than half of the patients (55.5 %) reported leprosy reaction: 18.3 % (138/753) had a RR and 5.4 % (41/753) had ENL. Leprosy reactions were more frequent in the first year following diagnosis, as seen in 27 % (205/753) of patients, while 19 % (142/753) developed reactions during subsequent follow-up. Similar frequencies of leprosy reactions and other clinical manifestations were observed in paucibacillary (PB) and multibacillary (MB) leprosy patients treated with U-MDT and regular MDT (R-MDT) (P = 0.43 and P = 0.61, respectively). Compared with PB patients, leprosy reactions were significantly more frequent in MB patients with a high BI, and more patients developed RR than ENL. However, RR and neuritis were also reported in patients with a negative BI. At baseline, the highest rate of ML Flow positivity was observed in patients with a positive BI, especially those who developed ENL, followed by patients who had neuritis and RR. Among reaction-free patients, 81.9 % were ML Flow positive, however, the differences were not statistically significant compared to reactional patients (P = 0.45). CONCLUSIONS: MB and PB patients treated with R-MDT and U-MDT showed similar frequencies of RR and other clinical manifestations. Positive ML Flow tests were associated with MB leprosy and BI positivity. However, ML Flow test results at baseline showed limited sensitivity and specificity for predicting the development of leprosy reactions.

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.

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.

Analysis of antigens of Mycobacterium leprae by interaction to sera IgG, IgM, and IgA response to improve diagnosis of leprosy.

Till 2010, several countries have declared less than one leprosy patient among population of 10,000 and themselves feeling as eliminated from leprosy cases. However, new leprosy cases are still appearing from all these countries. In this situation one has to be confident to diagnose leprosy. This review paper highlighted already explored antigens for diagnosis purposes and finally suggested better combinations of protein antigens of M. leprae versus immunoglobulin as detector antibody to be useful for leprosy diagnosis.

Anti-PGL1 salivary IgA/IgM, serum IgG/IgM, and nasal Mycobacterium leprae DNA in individuals with household contact with leprosy.

OBJECTIVES: Leprosy household contacts represent a group at high risk of developing the disease. The aim of this study was to detect Mycobacterium leprae subclinical infection in this group through serological and molecular parameters. METHODS: Serum anti-PGL1 IgG/IgM and salivary anti-PGL1 IgA/IgM was investigated using an ELISA, and nasal carriage of M. leprae DNA was detected by PCR, in leprosy household contacts of paucibacillary (PB) and multibacillary (MB) household leprosy patients (n=135), their index cases (n=30), and in persons living in a low endemic city (n=17). RESULTS: Salivary anti-PGL1 IgA and IgM and serum anti-PGL1 IgG showed good correlation comparing contacts and index cases (p<0.01, p<0.005, and p<0.0001, respectively). This was not observed for serum anti-PGL1 IgM (p>0.05). A high frequency of anti-PGL1 IgM positivity was found in IgG-negative samples (p<0.0001). For IgG-positive samples, IgM antibodies were also positive in most of the samples. None of the 17 volunteers living in a low endemic city presented seropositivity for IgG; however, two of them showed positivity for anti-PGL1 IgM. M. leprae DNA was found in the nasal swabs of nine out of the 85 MB household leprosy contacts (10.6%) and in three out of the 50 PB household leprosy contacts (6.0%). CONCLUSION: We strongly suggest that serum IgG/IgM and salivary anti-PGL1 IgA/IgM measurements are used to follow leprosy household contacts.

Lepromatous leprosy patients produce antibodies that recognise non-bilayer lipid arrangements containing mycolic acids

Non-bilayer phospholipid arrangements are three-dimensional structures that form when anionic phospholipids with an intermediate structure of the tubular hexagonal phase II are present in a bilayer of lipids. Antibodies that recognise these arrangements have been described in patients with antiphospholipid syndrome and/or systemic lupus erythematosus and in those with preeclampsia; these antibodies have also been documented in an experimental murine model of lupus, in which they are associated with immunopathology. Here, we demonstrate the presence of antibodies against non-bilayer phospholipid arrangements containing mycolic acids in the sera of lepromatous leprosy (LL) patients, but not those of healthy volunteers. The presence of antibodies that recognise these non-bilayer lipid arrangements may contribute to the hypergammaglobulinaemia observed in LL patients. We also found IgM and IgG anti-cardiolipin antibodies in 77% of the patients. This positive correlation between the anti-mycolic-non-bilayer arrangements and anti-cardiolipin antibodies suggests that both types of antibodies are produced by a common mechanism, as was demonstrated in the experimental murine model of lupus, in which there was a correlation between the anti-non-bilayer phospholipid arrangements and anti-cardiolipin antibodies. Antibodies to non-bilayer lipid arrangements may represent a previously unrecognised pathogenic mechanism in LL and the detection of these antibodies may be a tool for the early diagnosis of LL patients.

Lepromatous leprosy patients produce antibodies that recognise non-bilayer lipid arrangements containing mycolic acids.

Non-bilayer phospholipid arrangements are three-dimensional structures that form when anionic phospholipids with an intermediate structure of the tubular hexagonal phase II are present in a bilayer of lipids. Antibodies that recognise these arrangements have been described in patients with antiphospholipid syndrome and/or systemic lupus erythematosus and in those with preeclampsia; these antibodies have also been documented in an experimental murine model of lupus, in which they are associated with immunopathology. Here, we demonstrate the presence of antibodies against non-bilayer phospholipid arrangements containing mycolic acids in the sera of lepromatous leprosy (LL) patients, but not those of healthy volunteers. The presence of antibodies that recognise these non-bilayer lipid arrangements may contribute to the hypergammaglobulinaemia observed in LL patients. We also found IgM and IgG anti-cardiolipin antibodies in 77% of the patients. This positive correlation between the anti-mycolic-non-bilayer arrangements and anti-cardiolipin antibodies suggests that both types of antibodies are produced by a common mechanism, as was demonstrated in the experimental murine model of lupus, in which there was a correlation between the anti-non-bilayer phospholipid arrangements and anti-cardiolipin antibodies. Antibodies to non-bilayer lipid arrangements may represent a previously unrecognised pathogenic mechanism in LL and the detection of these antibodies may be a tool for the early diagnosis of LL patients.

A role for interleukin-5 in promoting increased immunoglobulin M at the site of disease in leprosy.

Leprosy is an infectious disease in which the clinical manifestations correlate with the type of immune response mounted to the pathogen, Mycobacterium leprae. To investigate which biological pathways or gene sets are over-represented in lepromatous (L-Lep) versus tuberculoid (T-Lep) patients that might be relevant in disease pathogenesis, we compared the gene expression profiles of L-lep versus T-lep skin lesions using knowledge-guided bioinformatic analysis, incorporating data on likely biological functions, including gene ontology information and regulatory data. Analysis of probe sets comparatively increased in expression in L-lep versus T-lep revealed multiple pathways and functional groups involving B-cell genes (P values all < 0.005) relevant to the dataset. Further pathways analysis of B-cell genes comparatively increased in expression in L-lep versus T-lep lesions revealed a potential network linking the expression of immunoglobulin M (IgM) and interleukin-5 (IL-5). Analysis of the leprosy lesions by immunohistology indicated that there was approximately 8% more IgM-positive cells in L-lep lesions than in T-lep lesions. Furthermore, IL-5 synergized in vitro with M. leprae to enhance total IgM secretion from peripheral blood mononuclear cells. This pathways analysis of leprosy in combination with our in vitro studies implicates a role for IL-5 in the increased IgM at the site of disease in leprosy.

Seropositivity to anti-phenolic glycolipid-I in leprosy cases, contacts and no known contacts of leprosy in an endemic and a non-endemic area in northeast Brazil.

The seroprevalence rates of IgM anti-phenolic glycolipid-I (PGL-I) antibodies in four study groups with differing exposure to Mycobacterium leprae in Ceará, Brazil were investigated between March 2005 and August 2006. The first three groups in a high prevalence area included 144 cases of leprosy, their 380 contacts and 317 participants with no known leprosy contact. The fourth group in a low prevalence area consisted of 87 participants with no known leprosy contact living in an area in which no cases of leprosy had been reported in the previous 6 months. Seropositivity and levels of IgM antibodies to PGL-I were investigated using ELISA. The seropositivity levels of anti-PGL-I among the different clinical forms of leprosy cases were 61% for lepromatous, 25% for tuberculoid and 27% indeterminate. The levels of anti-PGL-I antibodies in the endemic area differentiated leprosy cases from non-cases. However, the seropositivity was similar among contact cases (15.8%) and no known leprosy contact cases from high (15.1%) and low (13.8%) prevalence areas. The seropositivity of both contacts and no known contacts was much higher than previously reported among no known contacts in other endemic areas. The study indicates that anti-PGL-I antibodies are not useful as immunological markers of household leprosy contacts and no known leprosy contacts in endemic areas.

Correlation between beta-2-glycoprotein I gene polymorphism and anti-beta-2 glycoprotein I antibodies in patients with multibacillary leprosy.

Antiphospholipid antibodies, such as anti-beta2-glycoprotein I (beta2GPI), are present in multibacillary leprosy (MB) patients; however, MB patients do not usually present with antiphospholipid antibody syndrome (APS), which is characterized by thromboembolic phenomena (TEP). Rare cases of TEP occur in leprosy patients, but the physiopathology of this condition remains unclear. In this case-control study, we examined whether single-nucleotide polymorphisms (SNPs) of the beta2GPI gene contributed to the risk of leprosy and APS co-morbidity. SNPs Ser88Asn, Leu247Val, Cys306Gly and Trp316Ser were identified in 113 Brazilian leprosy patients. Additionally, anti-beta2GPI antibodies and plasma concentrations of beta2GPI were quantified. The Ser88Asn, Cys306Gly and Trp316Ser SNPs were not risk factors for APS in leprosy. A higher frequency of Val/Val homozygosity was observed in leprosy patients compared to controls (36 vs. 5%; P < 0.001). Forty-two percent of MB and 17% of paucibacillary leprosy patients were positive for anti-beta2GPI IgM (P = 0.014). There was no correlation between SNP Ser88Asn or Cys306Gly and anti-beta2GPI antibody levels. In MB patients with positive anti-beta2GPI IgM, the frequency of Val/Val homozygosity was higher than in controls (32 vs. 15%; P = 0.042). The frequency of the mutant allele Ser316 was higher in MB patients with positive rather than negative anti-beta2GPI IgM levels (6 vs. 0%; P = 0.040) and was greater than in the control group (6 vs. 1%; P = 0.034). The studied polymorphisms did not influence the plasma concentrations of beta2GPI. These results suggest that Leu247Val and Trp316Ser SNPs may represent genetic risk factors for anti-beta2GPI antibody production in MB patients.

Comparación de la técnica serológica ML flow y frotis cutáneas para evaluar la carga bacteriana en pacientes nuevos diagnosticados de Lepra / No disponible

Introducción: La técnica ML Flow es un ensayo inmunocromatográfico que detecta anticuerpos de tipo IgM glicolípido fenólico-I (PGL-1) M. leprae específico. Además de los frotis cutáneos teñidos mediante Ziehl-Neelsen puede ser útil en la clasificación de los pacientes de lepra para administrar el correspondiente tratamiento farmacológico. Objetivo: Este estudio revisa la relación entre los niveles de anticuerpos detectables mediante la técnica serológica semi-cuantitativa ML Flow y la carga bacteriana cuantificada mediante frotis cutáneo. Pacientes y métodos: Se obtuvieron frotis cutáneos de 135 pacientes nuevos diagnosticados de lepra en un servicio dermatológico de referencia en Brasil (registrados como índice bacteriológico – IB) y un resultado con el ML Flow (registrado cuantitativa y semi-cuantitativamente) en el momento de ser admitidos al estudio. Se calcularon la regresión logística y concordancia (índice kappa). Resultados: Los frotis cutáneos resultaron positivos en el 35.9% de los pacientes y el 57% de los pacientes eran seropositivos para el PGL-1. De entre los seropositivos, el 41.6% presentaban 5 o menos de 5 lesiones y el 65.8% presentaba la implicación de más de un nervio periférico. Los frotis resultaron positivos en sólo tres casos seronegativos (5.6%) y negativos en el 41.9% de pacientes seropositivos. Los pacientes con un IB+4 presentaban un OR de 3.3 de ser seropositivos en comparación con los de IB más bajo. Conclusiones: Hay una correlación entre el test serológico y los frotis cutáneos. Por tanto, un test ML Flow puede resultar útil para la clasificación clínica de la lepra, además de los frotis cutáneos que requieren una infraestructura de laboratorio y personal con experiencia (AU)

Introduction. The ML Flow test is an immunochromatographic assay that detects IgM antibodies against M. leprae-specific anti-phenolic glycolipid I (PGL-I). In addition to slit skin smears stained by the Ziehl-Neelsen technique, it can be helpful in the operational classification of leprosy patients for treatment purposes. Objective. This work studied the relationship between antibody levels as detected by semi-quantitative ML Flow serologic test and bacterial load as quantified by slit skin smear. Patients and methods. 135 patients with newly detected leprosy at the reference service in Sanitary Dermatology in Brazil had slit skin smears (registered as bacillary index – BI) and an ML Flow test (registered qualitatively and semi-quantitatively) performed at admission. A logistic regression and agreement measures (kappa index) were calculated. Results. Slit skin smears were positive in 35.9% of patients and 57% of patients were seropositive for PGL-1 antibodies. Among the seropositive patients, 41.6% had five or fewer skin lesions, and 65.8% had more than one peripheral nerve involved. Slit skin smears were positive in only three seronegative patients (5.6%), and negative in 41.9% of seropositive patients. Patients with a BI of 4had an OR of 3.3 for being seropositive in comparison to those with a low BI. Conclusions. There is a correlation between serologic test and slit skin smear results. Therefore, an ML Flow test may become a useful tool in the clinical classification of leprosy, besides slit skin smears, which require a proper laboratory infrastructure and experienced personnel (AU)

Leprosy serology using PGL-I: a systematic review.

Serology using a species-specific antigen for Mycobacterium leprae, PGL-I, could be a marker for the bacterial load of patients with leprosy. Various studies have identified the potential use of serology in the classification of patients for treatment purposes, case monitoring, identification of the risk of relapse and selection of household contacts with a higher risk of contracting the disease. A systematic review of the literature was conducted and 26 articles were included in this comparative analysis. The results of the use of PGL-I serology in different situations, its limitations and possible applications were evaluated. Studies show the efficacy of PGL-I serology in the classification of patients, treatment monitoring and as a predictive test for leprosy reactions. To improve early diagnosis and follow-up of the population at greatest risk of developing leprosy, the methodologies used in the past have yet to show a favorable cost-benefit ratio, although studies indicate that the use of the test might positively influence leprosy control programs. With simple and robust techniques, the use of PGL-I serology is viable.

Association of the ML Flow serologic test to slit skin smear.

A descriptive, exploratory study was conducted analyzing the association of covariables in the results of the ML Flow serological test and slit skin smear. A total of 60 leprosy cases diagnosed at the state Sanitary Dermatology Referral Center were investigated. Slit skin smear samples were collected from four sites and the results were expressed by the bacillary index. ML Flow was registered in both qualitative and semi-quantitative terms. Cohen's kappa coefficient was used to study the agreement with Landis and Koch's observer criteria for interpretation. For statistical analysis, the logistic regression model and Kruskal-Wallis test were used. ML Flow showed a strong association with slit skin smear results, since a gradual increase in BI was accompanied by a semi-quantitative rise in antibody levels measured by ML Flow, with 100% positivity in cases presenting a positive slit skin smear. Given its strong correlation to slit skin smear, the results of this study provide evidence that the ML Flow test could be a valuable auxiliary tool in the classification and treatment of leprosy patients.