Long-term storage stability of PGL-I coated ELISA plates for anti-Mycobacterium leprae IgM detection.

The assessment of ELISA plates coated with phenolic glycolipid-I/PGL-I revealed excellent stability during eight years of storage at room temperature, promoting consistent IgM antibody detection in multibacillary leprosy patients. These stable, standardized plates can significantly contribute to efficient leprosy serology research and support its widespread distribution and use in endemic countries.

Diagnostic Utility of Multiplex Polymerase Chain Reaction in Patients of Clinically Suspected Pure Neuritic Leprosy by Identifying Mycobacterium leprae in Skin Biopsy Samples and Nasal Swabs.

Pure neuritic leprosy (PNL) often remains underdiagnosed due to the lack of simple, reliable diagnostic tools to detect Mycobacterium leprae. This study aimed to investigate the utility of multiplex polymerase chain reaction (MPCR) in easily accessible and less invasive biopsy sites, including skin biopsy samples and nasal swabs (NSs), to detect M. leprae. A total of 30 (N = 30) clinically suspected and untreated patients with PNL were recruited. Nasal swabs and skin biopsy samples from the innervation territory of an "enlarged nerve" were collected. DNA was extracted and subjected to MPCR (targeting leprae-specific repetitive element [RLEP], 16S rRNA, and SodA genes) and RLEP-PCR (individual gene PCR). The PCR products were analyzed by 3% agarose gel electrophoresis. In 30 patients with clinically suspected PNL, 60% (N = 18) of skin biopsy samples and 53% (N = 16) of NSs were found positive for M. leprae DNA by MPCR, whereas only 23.3% (N = 7) of skin biopsy samples and 10% (N = 3) of NSs were found positive by RLEP-PCR. MPCR demonstrated a greater positivity rate than did RLEP-PCR for detection of M. leprae. Serologic positivity for anti-natural disaccharide-octyl conjugated with bovine serum albumin (ND-O-BSA) antibodies was 80% (16/20), including 35% (7/20) of PNL patients for which the skin MPCR was negative. Both serologic positivity and skin MPCR positivity were observed in 65% of patients (N = 20). Multiplex polymerase chain reaction is a useful tool for detection for M. leprae in skin biopsy samples and NSs in clinically suspected cases of PNL, with the added advantages of being less invasive and technically easier than nerve biopsy.

A case report and literature review: Mycobacterium leprae infection diagnosed by metagenomic next-generation sequencing of cerebrospinal fluid.

BACKGROUND: Leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae) that is responsible for deformities and irreversible peripheral nerve damage and has a broad spectrum of clinical and serological manifestations. Leprosy primarily affects the peripheral nerves and rarely presents with central nervous system involvement. Diagnosing leprosy can still be difficult in some cases, especially when the infection involves uncommon clinical manifestations and extracutaneous sites. Delayed diagnosis and treatment of leprosy may lead to irreversible damage and death. CASE PRESENTATION: We report a case of a 30-year-old female presenting with "repeated high fever with symptoms of headache for 14 days". On the day of admission, physical signs of lost eyebrows and scattered red induration patches all over her body were observed. The patient's diagnosis was based on the clinical characteristics using a combination of metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid (CSF) and slit-skin smear. After confirming Listeria meningitis and multibacillary leprosy with erythema nodosum leprosum (ENL), a type 2 reaction, she was treated with ampicillin sodium, dapsone, rifampicin, clofazimine, methylprednisolone, and thalidomide. At the 1-year follow-up, the frequency and severity of headaches have significantly decreased and a good clinical response with improved skin lesions was found. CONCLUSION: This case highlights the importance of considering leprosy, which is a rare and underrecognized disease, in the differential diagnosis of skin rashes with rheumatic manifestations, even in areas where the disease is not endemic, and physicians should be alerted about the possibility of central nervous system infections. In addition, mNGS can be used as a complementary diagnostic tool to traditional diagnostic methods to enhance the diagnostic accuracy of leprosy.

Systemic Lupus Erythematosus Complicated with Mycobacterium Leprae Infection: a Rare Case Report.

BACKGROUND: In December 2023, our hospital confirmed a case of systemic lupus erythematosus complicated with Mycobacterium leprae infection. The patient has extensive patchy erythema on the back and face, with obvious itching. There are multiple subcutaneous masses on both hands, some of which are accompanied by tenderness, wave sensation, and other symptoms. The patient's mother has a history of leprosy and close contact with the patient. The patient tested positive for syphilis antibodies 2 years ago and did not receive formal treatment. There is no other history of chronic illness. METHODS: Under local anesthesia, the left hand skin lesion was excised, followed by tissue pathological biopsy, acid-fast staining, mNGS, and serum Treponema pallidum antibody detection. RESULTS: Pathological biopsy results: A large number of foam-like histiocytes, lymphocytes, and plasma cells were mainly found in the superficial and deep layers of the dermis, as well as around the blood vessels and sweat glands in the subcutaneous fat. Cellulose-like degeneration is seen in some blood vessel walls. Tissue acid-fast staining: positive, tissue mNGS detection: Mycobacterium leprae. CLINICAL DIAGNOSIS: 1. Borderline leprosy, 2. Subacute cutaneous lupus erythematosus. Treat with methylprednisolone 32 mg qd po + aluminum magnesium suspension 15 mL tid po + calcium carbonate D3 tablets 0.6 g qd po + rifampicin 450 mg qd po + dapsone 100 mg qd. After 10 days of treatment, the patient improved and was discharged from the hospital. CONCLUSIONS: Mycobacterium leprae infection occurs during SLE treatment and is often difficult to distinguish from skin symptoms caused by SLE. In the clinical treatment of infectious diseases, the effect of conventional anti-bacterial drugs is not good. The auxiliary examination indicates severe infection and the routine culture is negative. The possibility of special pathogen infection should be considered in combination with the medical history. With the popularity of new detection methods such as mNGS, the importance of traditional smear detection methods cannot be ignored.

Buruli ulcer, tuberculosis and leprosy: Exploring the One Health dimensions of three most prevalent mycobacterial diseases: A narrative review.

ΟBJECTIVES: Although Buruli ulcer, tuberculosis, and leprosy are the three most common mycobacterial diseases, One Health dimensions of these infections remain poorly understood. This narrative review aims at exploring the scientific literature with respect to the presence of animal reservoir(s) and other environmental sources for the pathogens of these infections, their role in transmission to humans and the research on/practical implementation of One Health relevant control efforts. METHODS: The literature review was conducted using the online databases PubMed, Scopus, ProQuest and Google Scholar, reviewing articles that were written in English in the last 15 years. Grey literature, published by intergovernmental agencies, was also reviewed. RESULTS: For the pathogen of Buruli ulcer, evidence suggests possums as a possible animal reservoir and thus having an active role in disease transmission to humans. Cattle and some wildlife species are deemed as established animal reservoirs for tuberculosis pathogens, with a non-negligible proportion of infections in humans being of zoonotic origin. Armadillos constitute an established animal reservoir for leprosy pathogens with the transmission of the disease from armadillos to humans being deemed possible. Lentic environments, soil and other aquatic sources may represent further abiotic reservoirs for viable Buruli ulcer and leprosy pathogens infecting humans. Ongoing investigation and implementation of public health measures, targeting (sapro)zoonotic transmission can be found in all three diseases. CONCLUSION: Buruli ulcer, tuberculosis and leprosy exhibit important yet still poorly understood One Health aspects. Despite the microbiological affinity of the respective causative mycobacteria, considerable differences in their animal reservoirs, potential environmental sources and modes of zoonotic transmission are being observed. Whether these differences reflect actual variations between these diseases or rather knowledge gaps remains unclear. For improved disease control, further investigation of zoonotic aspects of all three diseases and formulation of One Health relevant interventions is urgently needed.

Prevalence of Mycobacterium leprae and Mycobacterium lepromatosis in roadkill armadillos in Brazil.

To evaluate the prevalence of Mycobacterium leprae and Mycobacterium lepromatosis in road killed armadillos identified along Brazilian regions, samples of liver, spleen, muscle, ear, nose and tail were collected on highways from 78 animals. The armadillos were of four different species, Cabassous tatouay, Dasypus novemcinctus, Dasypus septemcinctus and Euphractus sexcinctus. After DNA extraction from two tissues, specific primers were used for the detection of each pathogen using SYBR green qualitative Real-Time PCR, and amplicons were sequenced. The species with the highest prevalence was D. novemcinctus, mainly in the Central-West, South, and Southeast regions of Brazil. We detected M. leprae DNA in 32 (41 %) of the 78 individuals and M. lepromatosis DNA was not identified in any of the examined samples. The zoonotic component of leprosy may play a role in the transmission of the disease in endemic areas in which environmental conditions and contact with reservoirs must be investigated.

Nail fold capillaroscopy in leprosy: Unveiling the microvascular changes.

BACKGROUND: Leprosy, a chronic infectious disease, is associated with various nail changes. Its etiopathogenesis is multifaceted, with microvascular damage being crucial. Nail fold capillaroscopy (NFC) emerges as a novel tool for detecting early vascular deficits in leprosy. The study aimed to assess and provide a complete clinical characterization of NFC changes in leprosy patients. METHODS: It is an observational cross-sectional study, done over a period of 1.5 year (January 2021 to august 2022) in a tertiary care hospital, encompassing 60 patients diagnosed with leprosy (18-60 years). After obtaining informed consent; detailed history, complete cutaneous and neurological examinations were conducted. All fingernails and toenails were examined for clinical changes. Subsequently, onychoscopy was performed using USB type of video-dermatoscope (Model AM7115MZT Dino-lite), a non-invasive tool. This was followed by NFC which was done for all fingernails and images were recorded by single operator, which were then assessed for quantitative and qualitive changes and statistical analysis was conducted using SPSS v20, with mean capillary density compared using Student's t-test, morphological change frequencies assessed by proportions, and group comparisons made using Chi-square or Fischer exact tests, with a significance threshold of p < 0.05. RESULTS: Among the 60 patients, 39 were in the lepromatous group, which included both borderline lepromatous (BL) and lepromatous leprosy (LL) patients, and 17 were in the tuberculoid group, which included borderline tuberculoid (BT) leprosy patients; 23.3 % had Type 1 reactions, and 18.3 % had Type 2 reactions. Nail fold capillaroscopy (NFC) showed microvasculature changes in 93.3 % of patients. The average capillary density was 6.8 ± 1.5 capillaries per mm, with the lepromatous group having a lower density (6.5 ± 1.09) compared to the tuberculoid group (7.0 ± 0.86). The most common NFC changes in the tuberculoid group were tortuous capillaries (70 %), capillary dropouts, and dilated capillaries (both 64.7 %). In the lepromatous group, capillary dropouts (82 %) were most frequent, followed by tortuous (69 %), receding (69 %), and dilated capillaries (66 %). A dilated and prominent subpapillary plexus was more common in the lepromatous group (35 %, p = 0.04). Patients with trophic changes in the lepromatous group had more capillary dropouts and bizarre capillaries. Capillary dropouts, dilated capillaries, and visible subpapillary venous plexus were more prevalent in patients with Type 2 reactions. CONCLUSION: NFC changes are prevalent in both tuberculoid and lepromatous leprosy, which may be an indicator of peripheral vascular compromise and trophic changes, especially in lepromatous leprosy. NFC can be an auxiliary tool for detecting microvascular abnormalities in leprosy patients.

Molecular and spatial evaluation of small rodents and Didelphimorphis infected with Mycobacterium leprae in the southern Amazon, Brazil.

BACKGROUND: The high levels of recent transmission of leprosy worldwide demonstrate the necessity of epidemiologic surveillance to understand and control its dissemination. Brazil remains the second in number of cases around the world, indicating active transmission of Mycobacterium leprae (M. leprae) in the population. At this moment, there is a consensus that the bacillus is transmitted by inter-human contact, however, different serologic, molecular, and histopathological approaches indicate the existence of non-human transmission sources. METHODS AND RESULTS: The qPCR assay was used to amplify the molecular targets 16S RNAr and RLEP, in samples of liver, spleen, and ear of wild animals belonging to Didelphimorphia and Rodentia orders, in highly endemic areas of Mato Grosso, Brazil. The RLEP repetitive sequence was positive in 202 (89.0%) samples, with 96 (42.3%) of these also being positive for the 16S gene. Regarding the collection sites, it was observed that the animals were found in areas profoundly deforested, close to urban areas. CONCLUSIONS: Our results suggest that wild animals can play an important role in the maintenance of M. leprae in endemic regions with major anthropic action in Brazil. Therefore, integrating human, animal, and environmental health care with the One Health initiative is highly efficient for the development of effective strategies to contain and control leprosy in Brazil.

Leprosy Presenting as Distal Acquired Demyelinating Symmetric Variant of Chronic Inflammatory Demyelinating Polyneuropathy: An Atypical Manifestation of Hansan's Disease.

Leprosy, caused by the bacterium Mycobacterium leprae, is known to primarily affect the skin and peripheral nerves. We present a rare case of leprosy initially manifesting as demyelinating polyneuropathy. A 46-year-old female presented with progressive weakness, tingling, and numbness in her extremities. Nerve conduction studies revealed evidence of demyelination, prompting further investigations. Skin slit-skin smears confirmed the diagnosis of leprosy, with the presence of acid-fast bacilli. The patient was subsequently started on multidrug therapy, leading to significant clinical improvement. This case highlights the importance of considering leprosy as a differential diagnosis in patients presenting with demyelinating polyneuropathy, especially in endemic regions.

Identification of potential biomarkers of leprosy: A study based on GEO datasets.

Leprosy has a high rate of cripplehood and lacks available early effective diagnosis methods for prevention and treatment, thus novel effective molecule markers are urgently required. In this study, we conducted bioinformatics analysis with leprosy and normal samples acquired from the GEO database(GSE84893, GSE74481, GSE17763, GSE16844 and GSE443). Through WGCNA analysis, 85 hub genes were screened(GS > 0.7 and MM > 0.8). Through DEG analysis, 82 up-regulated and 3 down-regulated genes were screened(|Log2FC| > 3 and FDR < 0.05). Then 49 intersection genes were considered as crucial and subjected to GO annotation, KEGG pathway and PPI analysis to determine the biological significance in the pathogenesis of leprosy. Finally, we identified a gene-pathway network, suggesting ITK, CD48, IL2RG, CCR5, FGR, JAK3, STAT1, LCK, PTPRC, CXCR4 can be used as biomarkers and these genes are active in 6 immune system pathways, including Chemokine signaling pathway, Th1 and Th2 cell differentiation, Th17 cell differentiation, T cell receptor signaling pathway, Natural killer cell mediated cytotoxicity and Leukocyte transendothelial migration. We identified 10 crucial gene markers and related important pathways that acted as essential components in the etiology of leprosy. Our study provides potential targets for diagnostic biomarkers and therapy of leprosy.

Ancient Mycobacterium leprae genome reveals medieval English red squirrels as animal leprosy host.

Leprosy, one of the oldest recorded diseases in human history, remains prevalent in Asia, Africa, and South America, with over 200,000 cases every year.1,2 Although ancient DNA (aDNA) approaches on the major causative agent, Mycobacterium leprae, have elucidated the disease's evolutionary history,3,4,5 the role of animal hosts and interspecies transmission in the past remains unexplored. Research has uncovered relationships between medieval strains isolated from archaeological human remains and modern animal hosts such as the red squirrel in England.6,7 However, the time frame, distribution, and direction of transmissions remains unknown. Here, we studied 25 human and 12 squirrel samples from two archaeological sites in Winchester, a medieval English city well known for its leprosarium and connections to the fur trade. We reconstructed four medieval M. leprae genomes, including one from a red squirrel, at a 2.2-fold average coverage. Our analysis revealed a phylogenetic placement of all strains on branch 3 as well as a close relationship between the squirrel strain and one newly reconstructed medieval human strain. In particular, the medieval squirrel strain is more closely related to some medieval human strains from Winchester than to modern red squirrel strains from England, indicating a yet-undetected circulation of M. leprae in non-human hosts in the Middle Ages. Our study represents the first One Health approach for M. leprae in archaeology, which is centered around a medieval animal host strain, and highlights the future capability of such approaches to understand the disease's zoonotic past and current potential.

Bartonella henselae DNA detection in patients with type 1 leprosy reactions for more than six months.

Leprosy reactions are among the main causes of physical disability resulting from an infectious disease and can culminate in irreversible physical disabilities, therefore they should be considered a clinical emergency, as well as the elucidation of its cause. Co-infections are considered one of the main triggering causes of leprosy reactions, aggravating and maintaining these reactions for longer in these patients. After reporting a high rate of Bartonella henselae infection in patients with chronic type 2 leprosy reaction, 19/47 (40.4 %) compared to the control group, 9/50 (18.0 %), p = 0.0149, we conducted this study to observe the rate of infection by Bartonella sp. in a group of patients with chronic type 1 leprosy reactions. Blood samples from 14 patients with chronic type 1 leprosy reactions were analyzed by molecular and microbiological tests and compared. The results showed that, like patients with chronic type 2 leprosy reactions, this group of patients has a high proportion of B. henselae infection 6/14 (42.9 %), p = 0.88. We conclude that these bacteria can trigger chronic leprosy reactions and should be investigated in all chronic leprosy reactions patients. Summary Line: Our results showed that, like patients with chronic type 2 leprosy reactions, this group of patients has the same proportion of B. henselae DNA detection 6/14 (42.9 %), p = 0.88.

Leprosy reactions: Unraveling immunological mechanisms underlying tissue damage in leprosy patients.

Leprosy is a chronic granulomatous infectious and disabling disease caused by two mycobacteria, Mycobacterium leprae and Mycobacterium lepromatosis. Acute inflammatory responses, known as leprosy reactions, are significant contributors to disabilities. Three types of leprosy reactions have been identified based on excessive cytokine release (e.g. type 1) or the accumulation of immune complexes in tissues inducing multiorgan damage (e.g. types 2 and 3). The type of leprosy reaction has implications on treatment and management strategies, yet are not well understood by health workers caring for leprosy patients. We attempt to describe the immunologic mechanisms behind the different leprosy reactions and the rationale for tailoring clinical treatment and management to the particular type of leprosy reaction based on the underlying immunologic situation.

Bioarchaeological investigation of individuals with suspected multibacillary leprosy from the mediaeval leprosarium of St Mary Magdalen, Winchester, Hampshire, UK.

Introduction. We have examined four burials from the St Mary Magdalen mediaeval leprosarium cemetery in Winchester, Hampshire, UK. One (Sk.8) was a male child, two (Sk.45 and Sk.52) were adolescent females and the fourth (Sk.512) was an adult male. The cemetery was in use between the 10th and 12th centuries. All showed skeletal lesions of leprosy. Additionally, one of the two females (Sk.45) had lesions suggestive of multi-cystic tuberculosis and the second (Sk.52) of leprogenic odontodysplasia (LO), a rare malformation of the roots of the permanent maxillary incisors.Gap statement. Relatively little is known of the manifestations of lepromatous leprosy (LL) in younger individuals from the archaeological record.Aims and Methodology. To address this, we have used ancient DNA testing and osteological examination of the individuals, supplemented with X-ray and microcomputed tomography (micro-CT) scan as necessary to assess the disease status.Results and Conclusions. The presence of Mycobacterium leprae DNA was confirmed in both females, and genotyping showed SNP type 3I-1 strains but with a clear genotypic variation. We could not confirm Mycobacterium tuberculosis complex DNA in the female individual SK.45. High levels of M. leprae DNA were found within the pulp cavities of four maxillary teeth from the male child (Sk.8) with LO, consistent with the theory that the replication of M. leprae in alveolar bone may interfere with root formation at key stages of development. We report our biomolecular findings in these individuals and review the evidence this site has contributed to our knowledge of mediaeval leprosy.

Molecular epidemiological characteristics of Mycobacterium leprae in highly endemic areas of China during the COVID-19 epidemic.

Objectives: The present study analyzed the impact of the COVID-19 pandemic on the prevalence and incidence of new leprosy cases, as well as the diversity, distribution, and temporal transmission of Mycobacterium leprae strains at the county level in leprae-endemic provinces in Southwest China. Methods: A total of 219 new leprosy cases during two periods, 2018-2019 and 2020-2021, were compared. We genetically characterized 83 clinical isolates of M. leprae in Guizhou using variable number tandem repeats (VNTRs) and single nucleotide polymorphisms (SNPs). The obtained genetic profiles and cluster consequences of M. leprae were compared between the two periods. Results: There was an 18.97% decrease in the number of counties and districts reporting cases. Considering the initial months (January-March) of virus emergence, the number of new cases in 2021 increased by 167% compared to 2020. The number of patients with a delay of >12 months before COVID-19 (63.56%) was significantly higher than that during COVID-19 (48.51%). Eighty-one clinical isolates (97.60%) were positive for all 17 VNTR types, whereas two (2.40%) clinical isolates were positive for 16 VNTR types. The (GTA)9, (TA)18, (TTC)21 and (TA)10 loci showed higher polymorphism than the other loci. The VNTR profile of these clinical isolates generated five clusters, among which the counties where the patients were located were adjacent or relatively close to each other. SNP typing revealed that all clinical isolates possessed the single SNP3K. Conclusion: COVID-19 may have a negative/imbalanced impact on the prevention and control measures of leprosy, which could be a considerable fact for official health departments. Isolates formed clusters among counties in Guizhou, indicating that the transmission chain remained during the epidemic and was less influenced by COVID-19 preventative policies.

Leprosy mimicking autoimmune diseases: a case series.

OBJECTIVES: Leprosy is a chronic granulomatous disease caused by Mycobacterium leprae. Less frequently, there is involvement of the musculoskeletal system, and occurrence of systemic manifestation with non-specific symptoms such as fever, fatigue and myalgia. Therefore, leprosy can often mimic autoimmune diseases such as arthritis, vasculitis, or collagenosis and be mis-diagnosed. METHODS: This study describes a series of cases of leprosy mimicking autoimmune diseases in patients treated in the Rheumatology Department of our centre in the period 2019 to 2023. All patients were investigated regarding leprosy criteria and had clinical evaluation, serum markers, and histopathological analyses recorded. The diagnosis of leprosy was confirmed using skin biopsy followed by testing for acid-fast bacillus (AFB) or smear microscopy. RESULTS: Six patients who were initially investigated for autoimmune diseases were identified as diagnosed as leprosy cases, fulfilling both clinical and histopathologic criteria, two of whom presented with symptoms of polyarthritis with an inflammatory characteristic, two diffuse erythematous-violaceous lesions, three recurrent fever, three arthralgia, and one Raynaud's phenomenon, which are all characteristics present most frequently in rheumatologic diseases. CONCLUSIONS: We must consider the bacillary infection as a differential diagnosis of autoimmune diseases. Histopathological analysis is an important tool and the gold standard for diagnostic confirmation.

MicroRNAs correlate with bacillary index and genes associated to cell death processes in leprosy.

Mycobacterium leprae infects skin and peripheral nerves causing a broad of clinical forms. MicroRNAs (miRNAs) control immune mechanisms such as apoptosis, autophagy as well as to target genes leading to abnormal proliferation, metastasis, and invasion of cells. Herein we evaluated miRNAs expression for leprosy phenotypes in biopsies obtained from patients with and without reactions. We also correlated those miRNAs with both, bacillary index (BI) and genes involved in the micobacteria elimination process. Our results show a significant increase in the miR-125a-3p expression in paucibacillary (PB) patients vs multibacillary (MB) subjects (p = 0.007) and vs reversal reactions (RR) (p = 0.005), respectively. Likewise, there was a higher expression of miR-125a-3p in patients with erythema nodosum leprosum (ENL) vs MB without reactions (p = 0.002). Furthermore, there was a positive correlation between miR-125a-3p, miR-146b-5p and miR-132-5p expression and BI in patients with RR and ENL. These miRNAS were also correlated with genes such as ATG12 (miR-125a-3p), TNFRSF10A (miR-146b-5p), PARK2, CFLAR and STX7 (miR-132-5p). All together we underpin a role for these miRNAs in leprosy pathogenesis, implicating mechanisms such as apoptosis and autophagy in skin. The miR-125a-3p might have a distinct role associated with PB phenotype and ENL in MB patients.

The role of neurotrophin polymorphisms and susceptibility to neural damage in leprosy.

OBJECTIVES: Mycobacterium leprae is able to infect Schwann cells leading to neural damage. Neurotrophins are involved in nervous system plasticity and impact neural integrity during diseases. Investigate the association between single nucleotide polymorphisms in neurotrophin genes and leprosy phenotypes, especially neural damage. DESIGN: We selected single nucleotide polymorphisms in neurotrophins or their receptors genes associated with neural disorders: rs6265 and rs11030099 of brain-derived neurotrophic factor (BDNF), rs6330 of BDNF, rs6332 in NT3 and rs2072446 of P75NTR. The association of genetic frequencies with leprosy phenotypes was investigated in a case-control study. RESULTS: An association of the BDNF single nucleotide polymorphism rs11030099 with the number of affected nerves was demonstrated. The "AA+AC" genotypes were demonstrated to be protective against nerve impairment. However, this variation does not affect BDNF serum levels. BDNF is an important factor for myelination of Schwann cells and polymorphisms in this gene can be associated with leprosy outcome. Moreover, rs11030099 is located in the binding region for micro-RNA (miRNA) 26a that could be involved in control of BDNF expression. We demonstrated different expression levels of this miRNA in polar forms of leprosy. CONCLUSION: Our findings demonstrate for the first time an association between the polymorphism rs11030099 in the BDNF gene and neural commitment in leprosy and may indicate a possible role of miRNA-26a acting synergistically to these genetic variants in neural damage development.

Exploring the Cell Wall and Secretory Proteins of Mycobacterium leprae as Biomarkers.

The bacterial cell wall is composed of a wide variety of intricate proteins in addition to lipids, glycolipids, and polymers. Given the diversity of cell wall proteins among bacterial species, they are a feasible target for biomarker identification and characterization in clinical research and diagnosis of the disease. The slow growth rate of Mycobacterium leprae poses a major hurdle in the accurate diagnosis of leprosy before the onset of peripheral neuropathy. The use of biomarker- based diagnostic methods can help in preventing the spread and manifestation of leprosy. Despite many advances in research methods and techniques, there remains a knowledge gap regarding the cell wall proteomes of M. leprae that can be used as biomarkers. The cell wall and secretory proteins of M. leprae are the major focus of this review article. This article enfolds the characteristics and functions of M. leprae cell wall proteins and gives an insight into those cell wall proteins that are yet to be established as biomarkers. Tools and techniques used in cell wall extraction and biomarker identification can also be explored in this article.

Adenosine A2a receptor as a potential regulator of Mycobacterium leprae survival mechanisms: new insights into leprosy neural damage

Background: Leprosy is a chronic infectious disease caused by Mycobacterium leprae, which can lead to a disabling neurodegenerative condition. M. leprae preferentially infects skin macrophages and Schwann cells­glial cells of the peripheral nervous system. The infection modifies the host cell lipid metabolism, subverting it in favor of the formation of cholesterol-rich lipid droplets (LD) that are essential for bacterial survival. Although researchers have made progress in understanding leprosy pathogenesis, many aspects of the molecular and cellular mechanisms of host­pathogen interaction still require clarification. The purinergic system utilizes extracellular ATP and adenosine as critical signaling molecules and plays several roles in pathophysiological processes. Furthermore, nucleoside surface receptors such as the adenosine receptor A2AR involved in neuroimmune response, lipid metabolism, and neuron­glia interaction are targets for the treatment of different diseases. Despite the importance of this system, nothing has been described about its role in leprosy, particularly adenosinergic signaling (AdoS) during M. leprae­Schwann cell interaction. Methods: M. leprae was purified from the hind footpad of athymic nu/nu mice. ST88-14 human cells were infected with M. leprae in the presence or absence of specific agonists or antagonists of AdoS. nzymatic activity assays, fluorescence microscopy, Western blotting, and RT-qPCR nalysis were performed. M. leprae viability was investigated by RT-qPCR, and cytokines were evaluated by enzymelinked immunosorbent assay. Results: We demonstrated that M. leprae-infected Schwann cells upregulated CD73 and ADA and downregulated A2AR expression and the phosphorylation of the transcription factor CREB (p-CREB). On the other hand, activation of A2AR with its selective agonist, CGS21680, resulted in: 1) reduced lipid droplets accumulation and pro-lipogenic gene expression; 2) reduced production of IL-6 and IL-8; 3) reduced intracellular M. leprae viability; 4) increased levels of p-CREB. Conclusion: These findings suggest the involvement of the AdoS in leprosy neuropathogenesis and support the idea that M. leprae, by downmodulating the expression and activity of A2AR in Schwann cells, decreases A2AR downstream signaling, contributing to the maintenance of LD accumulation and intracellular viability of the bacillus.