Learning from Leprosy

Mycobacterium leprae and host immune transcriptomic signatures for reactional states in leprosy

Background

Mycobacterium leprae transcriptomic and human host immune gene expression signatures that demonstrate a plausible association with type I (T1R) and type II reactions (T2R) aid in early diagnosis, prevention of nerve damage and consequent demyelinating neuropathy in leprosy. The aim of the study is to identify M. leprae and host-associated gene-expression signatures that are associated with reactional states in leprosy.

Methods

The differentially expressed genes from the whole transcriptome of M. leprae were determined using genome-wide hybridization arrays with RNA extracted from skin biopsies of 20 T1R, 20 T2R and 20 non reactional controls (NR). Additionally, human immune gene-expressions were profiled using RT2-PCR profiler arrays and real-time qPCRs.

Results

The RNA quality was optimal in 16 NR, 18 T1R and 19 T2R samples. Whole transcriptome expression array of these samples revealed significant upregulation of the genes that encode integral and intrinsic membrane proteins, hydrolases and oxidoreductases. In T1R lesional skin biopsy specimens, the top 10 significantly upregulated genes are ML2064, ML1271, ML1960, ML1220, ML2498, ML1996, ML2388, ML0429, ML2030 and ML0224 in comparison to NR. In T2R, genes ML2498, ML1526, ML0394, ML1960, ML2388, ML0429, ML0281, ML1847, ML1618 and ML1271 were significantly upregulated. We noted ML2664 was significantly upregulated in T1R and repressed in T2R. Conversely, we have not noted any genes upregulated in T2R and repressed in T1R. In both T1R and T2R, ML2388 was significantly upregulated. This gene encodes a probable membrane protein and epitope prediction using Bepipred-2.0 revealed a distinct B-cell epitope. Overexpression of ML2388 was noted consistently across the reaction samples. From the host immune gene expression profiles, genes for CXCL9, CXCL10, CXCL2, CD40LG, IL17A and CXCL11 were upregulated in T1R when compared to the NR. In T2R, CXCL10, CXCL11, CXCL9, CXCL2 and CD40LG were upregulated when compared to the NR group.

Conclusion

A gene set signature involving bacterial genes ML2388, ML2664, and host immune genes CXCL10 and IL-17A can be transcriptomic markers for reactional states in leprosy.

Differential expression of programmed death 1 (PD-1) on various immune cells and its role in human leprosy

Leprosy is a chronic bacterial disease caused by Mycobacterium leprae. Leprosy patients have been found to have defects in T cells activation, which is critical to the clearance of the bacilli. Treg cell suppression is mediated by inhibitory cytokines such as IL10, IL-35 and TGF-β and its frequency is higher in leprosy patients. Activation and overexpression of programmed death 1 (PD-1) receptor is considered to one of the pathways to inhibit T-cell response in human leprosy. In the current study we address the effect of PD-1 on Tregs function and its immuno-suppressive function in leprosy patients. Flow cytometry was used to evaluate the expression of PD-1 and its ligands on various immune cells T cells, B cells, Tregs and monocytes. We observed higher expression of PD-1 on Tregs is associated with lower production of IL-10 in leprosy patients. PD-1 ligands on T cells, B cells, Tregs and monocytes found to be higher in the leprosy patients as compared to healthy controls. Furthermore, in vitro blocking of PD-1 restores the Tregs mediated suppression of Teff and increase secretion of immunosuppressive cytokine IL-10. Moreover, overexpression of PD-1 positively correlates with disease severity as well as Bacteriological Index (BI) among leprosy patients. Collectively, our data suggested that PD-1 overexpression on various immune cells is associated with disease severity in human leprosy. Manipulation and inhibition of PD-1 signaling pathway on Tregs alter and restore the Treg cell suppression activity in leprosy patients.

The immune-suppressive landscape in lepromatous leprosy revealed by single-cell RNA sequencing

Lepromatous leprosy (L-LEP), caused by the massive proliferation of Mycobacterium leprae primarily in macrophages, is an ideal disease model for investigating the molecular mechanism of intracellular bacteria evading or modulating host immune response. Here, we performed single-cell RNA sequencing of both skin biopsies and peripheral blood mononuclear cells (PBMCs) of L-LEP patients and healthy controls. In L-LEP lesions, we revealed remarkable upregulation of APOE expression that showed a negative correlation with the major histocompatibility complex II gene HLA-DQB2 and MIF, which encodes a pro-inflammatory and anti-microbial cytokine, in the subset of macrophages exhibiting a high expression level of LIPA. The exhaustion of CD8⁺ T cells featured by the high expression of TIGIT and LAG3 in L-LEP lesions was demonstrated. Moreover, remarkable enhancement of inhibitory immune receptors mediated crosstalk between skin immune cells was observed in L-LEP lesions. For PBMCs, a high expression level of APOE in the HLA-DR^highFBP1^high monocyte subset and the expansion of regulatory T cells were found to be associated with L-LEP. These findings revealed the primary suppressive landscape in the L-LEP patients, providing potential targets for the intervention of intracellular bacteria caused persistent infections.

A common approach for fighting tuberculosis and leprosy: controlling endoplasmic reticulum stress in myeloid-derived suppressor cells

Leprosy and tuberculosis are infectious diseases that are caused by bacteria, and both share primary risk factors. Mediators of these diseases are regulated by a heterogeneous immature population of myeloid cells called myeloid-derived suppressor cells (MDSCs) that exhibit immunosuppressive activity against innate and adaptive immunity. During pathological conditions, endoplasmic reticulum (ER) stress occurs in MDSCs, and high levels of ER stress affect MDSC-linked immunosuppressive activity. Investigating the role of ER stress in regulating immunosuppressive functions of MDSCs in leprosy and tuberculosis may lead to new approaches to treating these diseases. Here the authors discuss the immunoregulatory effects of ER stress in MDSCs as well as the possibility of targeting unfolded protein response elements of ER stress to diminish the immunosuppressive activity of MDSCs and reinvigorate diminished adaptive immune system responses that occur in leprosy and tuberculosis.

BCG-induced immunity profiles in household contacts of leprosy patients differentiate between protection and disease

Leprosy is an infectious disease caused by Mycobacterium leprae leading to irreversible disabilities along with social exclusion. Leprosy is a spectral disease for which the clinical outcome after M. leprae infection is determined by host factors. The spectrum spans from anti-inflammatory T helper-2 (Th2) immunity concomitant with large numbers of bacteria as well as antibodies against M. leprae antigens in multibacillary (MB) leprosy, to paucibacillary (PB) leprosy characterised by strong pro-inflammatory, Th1 as well as Th17 immunity. Despite decades of availability of adequate antibiotic treatment, transmission of M. leprae is unabated. Since individuals with close and frequent contact with untreated leprosy patients are particularly at risk to develop the disease themselves, prophylactic strategies currently focus on household contacts of newly diagnosed patients. It has been shown that BCG (re)vaccination can reduce the risk of leprosy. However, BCG immunoprophylaxis in contacts of leprosy patients has also been reported to induce PB leprosy, indicating that BCG (re)vaccination may tip the balance between protective immunity and overactivation immunity causing skin/nerve tissue damage. In order to identify who is at risk of developing PB leprosy after BCG vaccination, amongst individuals who are chronically exposed to M. leprae, we analyzed innate and adaptive immune markers in whole blood of household contacts of newly diagnosed leprosy patients in Bangladesh, some of which received BCG vaccination. As controls, individuals from the same area without known contact with leprosy patients were similarly assessed. Our data show the added effect of BCG vaccination on immune markers on top of the effect already induced by M. leprae exposure. Moreover, we identified BCG-induced markers that differentiate between protective and disease prone immunity in those contacts.

Potential Role of CXCL10 in Monitoring Response to Treatment in Leprosy Patients

The treatment of multibacillary cases of leprosy with multidrug therapy (MDT) comprises 12 doses of a combination of rifampicin, dapsone and clofazimine. Previous studies have described the immunological phenotypic pattern in skin lesions in multibacillary patients. Here, we evaluated the effect of MDT on skin cell phenotype and on the Mycobacterium leprae-specific immune response. An analysis of skin cell phenotype demonstrated a significant decrease in MRS1 (SR-A), CXCL10 (IP-10) and IFNG (IFN-γ) gene and protein expression after MDT release. Patients were randomized according to whether they experienced a reduction in bacillary load after MDT. A reduction in CXCL10 (IP-10) in sera was associated with the absence of a reduction in the bacillary load at release. Although IFN-γ production in response to M. leprae was not affected by MDT, CXCL10 (IP-10) levels in response to M. leprae increased in cells from patients who experienced a reduction in bacillary load after treatment. Together, our results suggest that CXCL10 (IP-10) may be a good marker for monitoring treatment efficacy in multibacillary patients.

In search of biomarkers for leprosy by unraveling the host immune response to Mycobacterium leprae

Mycobacterium leprae, the causative agent of leprosy, is still actively transmitted in endemic areas reflected by the fairly stable number of new cases detected each year. Recognizing the signs and symptoms of leprosy is challenging, especially at an early stage. Improved diagnostic tools, based on sensitive and specific biomarkers, that facilitate diagnosis of leprosy are therefore urgently needed. In this review, we address the challenges that leprosy biomarker research is facing by reviewing cell types reported to be involved in host immunity to M leprae. These cell types can be associated with different possible fates of M leprae infection being either protective immunity, or pathogenic immune responses inducing nerve damage. Unraveling these responses will facilitate the search for biomarkers. Implications for further studies to disentangle the complex interplay between host responses that lead to leprosy disease are discussed, providing leads for the identification of new biomarkers to improve leprosy diagnostics.

Mycobacterium leprae induces a tolerogenic profile in monocyte-derived dendritic cells via TLR2 induction of IDO

The enzyme IDO‐1 is involved in the first stage of tryptophan catabolism and has been described in both microbicidal and tolerogenic microenvironments. Previous data from our group have shown that IDO‐1 is differentially regulated in the distinctive clinical forms of leprosy. The present study aims to investigate the mechanisms associated with IDO‐1 expression and activity in human monocyte‐derived dendritic cells (mDCs) after stimulation with irradiated Mycobacterium leprae and its fractions. M. leprae and its fractions induced the expression and activity of IDO‐1 in human mDCs. Among the stimuli studied, irradiated M. leprae and its membrane fraction (MLMA) induced the production of proinflammatory cytokines TNF and IL‐6 whereas irradiated M. leprae and its cytosol fraction (MLSA) induced an increase in IL‐10. We investigated if TLR2 activation was necessary for IDO‐1 induction in mDCs. We observed that in cultures treated with a neutralizing anti‐TLR2 antibody, there was a decrease in IDO‐1 activity and expression induced by M. leprae and MLMA. The same effect was observed when we used a MyD88 inhibitor. Our data demonstrate that coculture of mDCs with autologous lymphocytes induced an increase in regulatory T (Treg) cell frequency in MLSA‐stimulated cultures, showing that M. leprae constituents may play opposite roles that may possibly be related to the dubious effect of IDO‐1 in the different clinical forms of disease. Our data show that M. leprae and its fractions are able to differentially modulate the activity and functionality of IDO‐1 in mDCs by a pathway that involves TLR2, suggesting that this enzyme may play an important role in leprosy immunopathogenesis.

Household Contacts of Leprosy Patients in Endemic Areas Display a Specific Innate Immunity Profile

Leprosy is a chronic infectious disease, caused by Mycobacterium leprae, that can lead to severe life-long disabilities. The transmission of M. leprae is continuously ongoing as witnessed by the stable new case detection rate. The majority of exposed individuals does, however, not develop leprosy and is protected from infection by innate immune mechanisms. In this study the relation between innate immune markers and M. leprae infection as well as the occurrence of leprosy was studied in household contacts (HCs) of leprosy patients with high bacillary loads. Serum proteins associated with innate immunity (ApoA1, CCL4, CRP, IL-1Ra, IL-6, IP-10, and S100A12) were determined by lateral flow assays (LFAs) in conjunction with the presence of M. leprae DNA in nasal swabs (NS) and/or slit-skin smears (SSS). The HCs displayed ApoA1 and S100A12 levels similar to paucibacillary patients and could be differentiated from endemic controls based on the levels of these markers. In the 31 households included the number (percentage) of HCs that were concomitantly diagnosed with leprosy, or tested positive for M. leprae DNA in NS and SSS, was not equally divided. Specifically, households where M. leprae infection and leprosy disease was not observed amongst members of the household were characterized by higher S100A12 and lower CCL4 levels in whole blood assays of HCs in response to M. leprae. Lateral flow assays provide a convenient diagnostic tool to quantitatively measure markers of the innate immune response and thereby detect individuals which are likely infected with M. leprae and at risk of developing disease or transmitting bacteria. Low complexity diagnostic tests measuring innate immunity markers can therefore be applied to help identify who should be targeted for prophylactic treatment.

Macrophage Polarization in Leprosy-HIV Co-infected Patients

In HIV-infected individuals, a paradoxical clinical deterioration may occur in preexisting leprosy when highly active antiretroviral therapy (HAART)-associated reversal reaction (RR) develops. Leprosy–HIV co-infected patients during HAART may present a more severe form of the disease (RR/HIV), but the immune mechanisms related to the pathogenesis of leprosy–HIV co-infection remain unknown. Although the adaptive immune responses have been extensively studied in leprosy–HIV co-infected individuals, recent studies have described that innate immune cells may drive the overall immune responses to mycobacterial antigens. Monocytes are critical to the innate immune system and play an important role in several inflammatory conditions associated with chronic infections. In leprosy, different tissue macrophage phenotypes have been associated with the different clinical forms of the disease, but it is not clear how HIV infection modulates the phenotype of innate immune cells (monocytes or macrophages) during leprosy. In the present study, we investigated the phenotype of monocytes and macrophages in leprosy–HIV co-infected individuals, with or without RR. We did not observe differences between the monocyte profiles in the studied groups; however, analysis of gene expression within the skin lesion cells revealed that the RR/HIV group presents a higher expression of macrophage scavenger receptor 1 (MRS1), CD209 molecule (CD209), vascular endothelial growth factor (VEGF), arginase 2 (ARG2), and peroxisome proliferator-activated receptor gamma (PPARG) when compared with the RR group. Our data suggest that different phenotypes of tissue macrophages found in the skin from RR and RR/HIV patients could differentially contribute to the progression of leprosy.

Diet and nutrition: An important risk factor in leprosy

Leprosy, once considered as poor man's disease may cause severe neurological complications and physical disabilities. Classification of leprosy depends upon the cell mediated and humoral immune responses of the host, from tuberculoid to lepromatous stage. Current therapy to prevent the disease is not only very lengthy but also consists of expensive multiple antibiotics in combination. Treatment and the duration depend on the bacillary loads, from six months in paucibacillary to a year in multibacillary leprosy. Although as per WHO recommendations, these antibiotics are freely available but still out of reach to patients of many rural areas of the world. In this review, we have focused on the nutritional aspect during the multi-drug therapy of leprosy along with the role of nutrition, particularly malnutrition, on susceptibility of Mycobacterium leprae and development of clinical symptoms. We further discussed the diet plan for the patients and how diet plans can affect the immune responses during the disease.

Revisiting the tuberculosis and leprosy cross-immunity hypothesis: Expanding the dialogue between immunology and paleopathology

OBJECTIVE

Our primary objective is to re-visit the tuberculosis and leprosy cross-immunity. hypothesis through the careful integration of immunology and paleopathology.

METHODS

Using an integrated theoretical analysis that evaluates clinical literature on human innate immunological responses, paleomicrobiology, bioarchaeology, and paleopathology, we develop a multifactorial model.

RESULTS

Past populations do not represent homogeneous immunological landscapes, and therefore it is likely that leprosy in Medieval Europe did not uniformly decline due to cross-immunity.

CONCLUSIONS

We recommend that bioarchaeological reconstructions of past disease experience take into consideration models that include variation in immune function based on past environments and social contexts. This provides a unique opportunity to conduct comprehensive analyses on complex immunological processes.

SIGNIFICANCE

Extrapolating results from experimental immunology to larger populations elucidates complexities of disease cross-immunity and highlights the importance of synthesizing archaeological, social, paleopathological and biological data as a means of understanding disease in the past.

LIMITATIONS

All extrapolations from data produced from in vitro studies to past populations, using living donors, pose significant limitations where, among other factors, the full reconstruction of past environmental and social contexts can frequently be sparse or incomplete.

SUGGESTIONS FOR FUTURE RESEARCH

To reduce the limitations of integrating experimental immunology with bioarchaeological reconstructions (i.e. how to use skeletal samples to reconstruct inflammatory phenotypes), we propose that osteoimmunology, or the study of the interplay between immune cells and bone cells, should be considered a vital discipline and perhaps the foundation for the expansion of paleoimmunology.

Evaluation of Immunodiagnostic Tests for Leprosy in Brazil, China and Ethiopia

Leprosy remains persistently endemic in several low- or middle income countries. Transmission is still ongoing as indicated by the unabated rate of leprosy new case detection, illustrating the insufficiency of current prevention methods. Therefore, low-complexity tools suitable for large scale screening efforts to specifically detect M. leprae infection and diagnose disease are required. Previously, we showed that combined detection of cellular and humoral markers, using field-friendly lateral flow assays (LFAs), increased diagnostic potential for detecting leprosy in Bangladesh compared to antibody serology alone. In the current study we assessed the diagnostic performance of similar LFAs in three other geographical settings in Asia, Africa and South-America with different leprosy endemicity. Levels of anti-PGL-I IgM antibody (humoral immunity), IP-10, CCL4 and CRP (cellular immunity) were measured in blood collected from leprosy patients, household contacts and healthy controls from each area. Combined detection of these biomarkers significantly improved the diagnostic potential, particularly for paucibacillary leprosy in all three regions, in line with data obtained in Bangladesh. These data hold promise for the use of low-complexity, multibiomarker LFAs as universal tools for more accurate detection of M. leprae infection and different phenotypes of clinical leprosy.

Phenotypic and functional features of innate and adaptive immunity as putative biomarkers for clinical status and leprosy reactions

The aim of this study was to identify phenotypic and functional biomarkers associated with distinct clinical status of leprosy or leprosy reactions. The study included tuberculoid/borderline (BB/BT/T) and lepromatous (BL/L) leprosy poles as well as Type-1 and Type-2 leprosy reactions along with healthy controls (NI). A range of peripheral blood biomarkers of innate (neutrophils - NEU and monocytes - MON) and adaptive immunity (CD4⁺ and CD8⁺ T-cells) were evaluated ex vivo and upon in vitro stimuli with M. leprae antigen. Data analysis allowed the selection of NEUTLR4⁺ (ex vivo) and CD4⁺IL-10⁺ (in vitro) as universal biomarkers increased in all leprosy patients and those exhibiting leprosy reactions. A range of biomarkers were commonly found in both poles of leprosy patients, including decreased levels of MONTGF-β⁺ (ex vivo) and increased levels of MONTNF-α⁺, CD4⁺TGF-β⁺, CD8⁺TLR2⁺, CD8⁺TNF-α⁺, CD8⁺IL-4⁺ and CD8⁺TGF-β⁺ (in vitro). Noteworthy was that MONHLA-DR⁺ (ex vivo) and CD8⁺IL-10⁺ (in vitro) were particularly found in BL/L patients. Leprosy patients with Type-1 reaction exhibited a larger list of altered biomarkers, mainly involving activation markers (TLR2, TLR4, HLA-DR and DAF-2T) in NEU and MON along with CD4⁺ and CD8⁺ cells. In summary, this study provided insights about immunological features of leprosy poles and leprosy reactional episodes with putative applicability, including novel biomarkers for complementary diagnosis and future therapeutic approaches in clinical studies.

Innate Immune Responses in Leprosy

Leprosy is an infectious disease that may present different clinical forms depending on host immune response to Mycobacterium leprae. Several studies have clarified the role of various T cell populations in leprosy; however, recent evidences suggest that local innate immune mechanisms are key determinants in driving the disease to its different clinical manifestations. Leprosy is an ideal model to study the immunoregulatory role of innate immune molecules and its interaction with nervous system, which can affect homeostasis and contribute to the development of inflammatory episodes during the course of the disease. Macrophages, dendritic cells, neutrophils, and keratinocytes are the major cell populations studied and the comprehension of the complex networking created by cytokine release, lipid and iron metabolism, as well as antimicrobial effector pathways might provide data that will help in the development of new strategies for leprosy management.

Analysis of CTLA-4+49A/G gene polymorphism in cases with leprosy of Azerbaijan, Northwest Iran

Leprosy, which is developed by the obligate intracellular Mycobacterium leprae (ML); has different manifestations, associated with the host immune responses. The protective immune response against ML includes T-cell-mediated immunity. The CTLA-4 has a great impact as a negative regulator of the immune response and maintenance of peripheral tolerance. This study analyzed the relationship between CTLA-4+49A/G gene polymorphism and clinical manifestation of leprosy disease and susceptibility among the Azeri population living Northwest Iran. One hundred and ninety-two leprosy patients and 185 healthy controls participated in the study. CTLA-4+49A/G genotyping was conducted via tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) analysis. The allelic and genotypic frequencies of +49A/G gene polymorphism were similar in controls and patients. However, older ages, older age of onset and over-representation in male were observed in lepromatous leprosy patient carriers of GG genotype. The current study demonstrates that although CTLA-4+49A/G polymorphism was not correlated with a higher genetic risk for leprosy, the presence of a GG genotype was associated with older ages, older age of onset and over-representation in male in Iranian Azeri population.

Field-friendly serological tests for determination of M. leprae-specific antibodies

Early detection of leprosy is key to reduce the ongoing transmission. Antibodies directed against M. leprae PGL-I represent a useful biomarker for detecting multibacillary (MB) patients. Since efficient leprosy diagnosis requires field-friendly test conditions, we evaluated two rapid lateral flow assays (LFA) for detection of Mycobacterium leprae-specific antibodies: the visual immunogold OnSite Leprosy Ab Rapid test [Gold-LFA] and the quantitative, luminescent up-converting phosphor anti-PGL-I test [UCP-LFA]. Test performance was assessed in independent cohorts originating from three endemic areas. In the Philippine cohort comprising patients with high bacillary indices (BI; average:4,9), 94%(n = 161) of MB patients were identified by UCP-LFA and 78%(n = 133) by Gold-LFA. In the Bangladeshi cohort, including mainly MB patients with low BI (average:1), 41%(n = 14) and 44%(n = 15) were detected by UCP-LFA and Gold-LFA, respectively. In the third cohort of schoolchildren from a leprosy hyperendemic region in Brazil, both tests detected 28%(n = 17) seropositivity. Both rapid tests corresponded well with BI(p < 0.0001), with a fairly higher sensitivity obtained with the UCP-LFA assay. However, due to the spectral character of leprosy, additional, cellular biomarkers are required to detect patients with low BIs. Therefore, the UCP-LFA platform, which allows multiplexing with differential biomarkers, offers more cutting-edge potential for diagnosis across the whole leprosy spectrum.

Coronins and their role in immunological phenomena

Coronins are a large family of proteins occurring in many eukaryotes. In mammals, seven coronin genes have been identified, evidencing that coronins 1 to 6 present classic coronin structure, while coronin 7 is a tandem coronin particle, without a spiral domain, although the best characterised coronin, in terms of both structure and function, is the mammalian coronin 1. It has been proven that they are related to regulation of actin dynamics, e.g. as a result of interaction with the complex of proteins Arp2/3. These proteins also modulate the activity of immune system cells, including lymphocyte T and B cells, neutrophils and macrophages. They are involved in bacterial infections with Mycobacterium tuberculosis, M. leprae and Helicobacter pylori and participate in the response to viral infections, e.g. infections of lymphocytic choriomeningitis virus (LCMV) and vesicular stomatitis Indiana virus (VSV). Also their involvement in autoimmune diseases such as lupus erythematosus has been recorded.

The Concept of Wind in Traditional Chinese Medicine

The use of folk medicine has been widely embraced in many developed countries under the name of traditional, complementary and alternative medicine (TCAM) and is now becoming the mainstream in the UK and the rest of Europe, as well as in North America and Australia. Diversity, easy accessibility, broad continuity, relatively low cost, base levels of technological inputs, fewer side effects, and growing economic importance are some of the positive features of folk medicine. In this framework, a critical need exists to introduce the practice of folk medicine into public healthcare if the goal of reformed access to healthcare facilities is to be achieved. The amount of information available to public health practitioners about traditional medicine concepts and the utilization of that information are inadequate and pose many problems for the delivery of primary healthcare globally. Different societies have evolved various forms of indigenous perceptions that are captured under the broad concept of folk medicine, e.g., Persian, Chinese, Grecian, and African folk medicines, which explain the lack of universally accepted definitions of terms. Thus, the exchange of information on the diverse forms of folk medicine needs to be facilitated. Various concepts of Wind are found in books on traditional medicine, and many of those go beyond the boundaries established in old manuscripts and are not easily understood. This study intends to provide information, context, and guidance for the collection of all important information on the different concepts of Wind and for their simplification. This new vision for understanding earlier Chinese medicine will benefit public health specialists, traditional and complementary medicine practitioners, and those who are interested in historical medicine by providing a theoretical basis for the traditional medicines and the acupuncture that is used to eliminate Wind in order to treat various diseases.

Quantitative lateral flow strip assays as User-Friendly Tools To Detect Biomarker Profiles For Leprosy

Leprosy is a debilitating, infectious disease caused by Mycobacterium leprae. Despite the availability of multidrug therapy, transmission is unremitting. Thus, early identification of M. leprae infection is essential to reduce transmission. The immune response to M. leprae is determined by host genetics, resulting in paucibacillary (PB) and multibacillary (MB) leprosy associated with dominant cellular or humoral immunity, respectively. This spectral pathology of leprosy compels detection of immunity to M. leprae to be based on multiple, diverse biomarkers. In this study we have applied quantitative user friendly lateral flow assays (LFAs) for four immune markers (anti-PGL-I antibodies, IL-10, CCL4 and IP-10) for whole blood samples from a longitudinal BCG vaccination field-trial in Bangladesh. Different biomarker profiles, in contrast to single markers, distinguished M. leprae infected from non-infected test groups, patients from household contacts (HHC) and endemic controls (EC), or MB from PB patients. The test protocol presented in this study merging detection of innate, adaptive cellular as well as humoral immunity, thus provides a convenient tool to measure specific biomarker profiles for M. leprae infection and leprosy utilizing a field-friendly technology.

Complement activation in leprosy: a retrospective study shows elevated circulating terminal complement complex in reactional leprosy

Mycobacterium leprae infection gives rise to the immunologically and histopathologically classified spectrum of leprosy. At present, several tools for the stratification of patients are based on acquired immunity markers. However, the role of innate immunity, particularly the complement system, is largely unexplored. The present retrospective study was undertaken to explore whether the systemic levels of complement activation components and regulators can stratify leprosy patients, particularly in reference to the reactional state of the disease. Serum samples from two cohorts were analysed. The cohort from Bangladesh included multi-bacillary (MB) patients with (n = 12) or without (n = 46) reaction (R) at intake and endemic controls (n = 20). The cohort from Ethiopia included pauci-bacillary (PB) (n = 7) and MB (n = 23) patients without reaction and MB (n = 15) patients with reaction. The results showed that the activation products terminal complement complex (TCC) (P ≤ 0·01), C4d (P ≤ 0·05) and iC3b (P ≤ 0·05) were specifically elevated in Bangladeshi patients with reaction at intake compared to endemic controls. In addition, levels of the regulator clusterin (P ≤ 0·001 without R; P < 0·05 with R) were also elevated in MB patients, irrespective of a reaction. Similar analysis of the Ethiopian cohort confirmed that, irrespective of a reaction, serum TCC levels were increased significantly in patients with reactions compared to patients without reactions (P ≤ 0·05). Our findings suggests that serum TCC levels may prove to be a valuable tool in diagnosing patients at risk of developing reactions.

Tuberculosis and Leprosy: Classical Granulomatous Diseases in the Twenty-First Century

Leprosy and tuberculosis are chronic mycobacterial infections that elicit granulomatous inflammation. Both infections are curable, but granulomatous injury to cutaneous structures, including cutaneous nerves in leprosy, may cause permanent damage. Both diseases are major global concerns: tuberculosis for its high prevalence and mortality, and leprosy for its persistent global presence and high rate of neuropathic disability. Cutaneous manifestations of both leprosy and tuberculosis are frequently subtle and challenging in dermatologic practice and often require a careful travel and social history and a high index of suspicion.

Longitudinal immune profiles in type 1 leprosy reactions in Bangladesh, Brazil, Ethiopia and Nepal

Background

Acute inflammatory reactions are a frequently occurring, tissue destructing phenomenon in infectious- as well as autoimmune diseases, providing clinical challenges for early diagnosis. In leprosy, an infectious disease initiated by Mycobacterium leprae (M. leprae), these reactions represent the major cause of permanent neuropathy. However, laboratory tests for early diagnosis of reactional episodes which would significantly contribute to prevention of tissue damage are not yet available.

Although classical diagnostics involve a variety of tests, current research utilizes limited approaches for biomarker identification. In this study, we therefore studied leprosy as a model to identify biomarkers specific for inflammatory reactional episodes.

Methods

To identify host biomarker profiles associated with early onset of type 1 leprosy reactions, prospective cohorts including leprosy patients with and without reactions were recruited in Bangladesh, Brazil, Ethiopia and Nepal. The presence of multiple cyto-/chemokines induced by M. leprae antigen stimulation of peripheral blood mononuclear cells as well as the levels of antibodies directed against M. leprae-specific antigens in sera, were measured longitudinally in patients.

Results

At all sites, longitudinal analyses showed that IFN-γ-, IP-10-, IL-17- and VEGF-production by M. leprae (antigen)-stimulated PBMC peaked at diagnosis of type 1 reactions, compared to when reactions were absent. In contrast, IL-10 production decreased during type 1 reaction while increasing after treatment. Thus, ratios of these pro-inflammatory cytokines versus IL-10 provide useful tools for early diagnosing type 1 reactions and evaluating treatment. Of further importance for rapid diagnosis, circulating IP-10 in sera were significantly increased during type 1 reactions. On the other hand, humoral immunity, characterized by M. leprae-specific antibody detection, did not identify onset of type 1 reactions, but allowed treatment monitoring instead.

Conclusions

This study identifies immune-profiles as promising host biomarkers for detecting intra-individual changes during acute inflammation in leprosy, also providing an approach for other chronic (infectious) diseases to help early diagnose these episodes and contribute to timely treatment and prevention of tissue damage.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1128-0) contains supplementary material, which is available to authorized users.

Association of TNF -1031 C/C as a potential protection marker for leprosy development in Amazonas state patients, Brazil

Polymorphisms present in the TNF promoter region has shown to influence the gene transcription. Leprosy displays different clinical manifestations according to the immune responses of the individual infected with Mycobacterium leprae. In this study, we evaluated the single nucleotide polymorphisms (SNPs) -238 G/A (rs361525), -308 G/A (rs1800629), -857 C/T (rs1799724), -863 A/C (rs1800630) and -1031 T/C (rs1799964) in the promoter region of the TNF to see whether these SNPs influence host-susceptibility to leprosy and the different clinical manifestation. Nucleotide sequencing was performed with DNA samples from 108 leprosy patients and 253 control subjects. An association between -1031 C/C genotype and protection from leprosy was observed when leprosy patients were compared to controls (OR 0.11; 95% CI=0.01-0.82; p=0.012). The -857 C/T genotype may be associated with susceptibility to leprosy (OR=1.81; 95% CI=1.09-3.00; p=0.028). Similar genotype and allele frequencies for the SNPs -308 G/A and -238 G/A were observed between leprosy patients and control subjects. Altogether, TNF polymorphisms in the promoter region may be predictive of leprosy outcome.

The role of ERBB2 gene polymorphisms in leprosy susceptibility

Mycobacterium leprae infects skin and peripheral nerves causing deformities and disability. The M. leprae bacterium binds to ErbB2 on the Schwann cell surface causing demyelination and favoring spread of the bacilli and causing nerve injury. Polymorphisms at the ERBB2 gene were previously investigated as genetic risk factors for leprosy in two Brazilian populations but with inconsistent results. Herein we extend the analysis of ERBB2 variants to a third geographically distinct population in Brazil. Our results show that there is no association between the genotyped SNPs and the disease (p > 0.05) in this population. A gene set or pathway analysis under the genomic region of ERBB2 will be necessary to clarify its regulation under M. leprae stimulus.

On the age of leprosy

Leprosy is a chronic infection of the skin and nerves caused by Mycobacterium leprae and the newly discovered Mycobacterium lepromatosis. Human leprosy has been documented for millennia in ancient cultures. Recent genomic studies of worldwide M. leprae strains have further traced it along global human dispersals during the past ∼ 100,000 years. Because leprosy bacilli are strictly intracellular, we wonder how long humans have been affected by this disease-causing parasite. Based on recently published data on M. leprae genomes, M. lepromatosis discovery, leprosy bacilli evolution, and human evolution, it is most likely that the leprosy bacilli started parasitic evolution in humans or early hominids millions of years ago. This makes leprosy the oldest human-specific infection. The unique adaptive evolution has likely molded the indolent growth and evasion from human immune defense that may explain leprosy pathogenesis. Accordingly, leprosy can be viewed as a natural consequence of a long parasitism. The burden of leprosy may have affected minor selection on human genetic polymorphisms.

Protein tyrosine phosphatase non-receptor type 22 gene polymorphism C1858T is not associated with leprosy in Azerbaijan, Northwest Iran

BACKGROUND

Leprosy (Hansen's disease) is a human chronic granulomatous infectious disease caused by Mycobacterium leprae. Several types of study support a role for host genetics in susceptibility to leprosy. The protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene encodes an intracellular lymphoid protein tyrosine phosphatase that has been shown to play a negative regulatory role in T-cell activation.

AIMS

The aim of the present study was to find out associating the PTPN22 C1858T (R620W) polymorphism and leprosy in the Azeri population from Northwest Iran.

MATERIALS AND METHODS

A total of 153 treated leprosy patients and 197 healthy and ethnic matched controls entered this study. We used restriction fragment length polymorphism method to type PTPN22 C1858T polymorphism.

RESULTS

There was no significant difference in distribution of genotype and allele frequencies of PTPN22 C1858T polymorphism between leprosy patients and controls (P = 0.641 and 0.645; respectively). Moreover, there was no significant association between different clinical findings (karnofsky performance status score, clinical forms and manifestations of leprosy) and PTPN22 C1858T polymorphism. Data showed a low frequency of the minor (T) allele by 2.3% in leprosy and 1.5% in healthy individuals.

CONCLUSIONS

The PTPN22 C1858T (R620W) is not relevant in susceptibility to leprosy in the Azeri population of Northwest Iran.

Polymorphisms assessment in the promoter region of IL12RB2 in Amazon leprosy patients

Leprosy displays a wide clinical spectrum that is dependent of the type of immune response. We investigate here whether polymorphisms in the promoter region of the IL12RB2 gene are associated with susceptibility or resistance to clinical forms of leprosy. Nucleotide sequencing of the promoter region of IL12RB2 encompassing SNPs -1035 A/G, -1033 T/C, -1023 A/G, -650 del/G and -464 A/G was performed on DNA samples from 105 leprosy patients and 108 healthy controls. However, none of the SNPs were associated with susceptibility to the disease or any of its clinical forms. Similarly, haplotype analysis did not show any association. The haplotype -1035A/-1033T/-650G/-464A was prevalent, and homozygosity for this haplotype was associated to a lower distribution of CD4(+) T cells (p=0.041). Our data suggest that polymorphisms present in the promoter region of IL12RB2 may not be associated with susceptibility to leprosy or its clinical forms.

Association between the IFNG +874A/T gene polymorphism and leprosy resistance: a meta-analysis

Previous studies identified the variant IFNG +874A/T (rs2430561) in the first intron of the gene in association with mycobacterial infection, especially tuberculosis and leprosy. The aim of this investigation was to analyze the protective role of the T allele in relation to leprosy using a meta-analysis evaluation. Thus, 1573 patients and 1914 controls were included and analyzed in fixed effects model. The T allele is associated with a protective effect for leprosy under the dominant model (pooled OR=0.83, 95% CI=0.72-0.96, p=0.011) suggesting that carriers of the IFNG +874T allele may be protected from developing leprosy. The T allele has been suggested to correlate with high interferon-γ levels. A phenotype with high IFN-γ producing and an increased inflammatory profile may account for these findings. This meta-analysis suggests that IFNG +874T allele is associated with leprosy resistance.

On guard: coronin proteins in innate and adaptive immunity

Recent work has implicated members of the evolutionarily conserved family of coronin proteins - in particular coronin 1 - in immune homeostasis. Coronins are involved in processes as diverse as pathogen survival in phagocytes and homeostatic T cell signalling. Notably, in both mice and humans, coronin mutations are associated with immune deficiencies and resistance to autoimmunity. In this article, we review what is currently known about these conserved molecules and discuss a potential common mechanism that underlies their diverse activities, which seem to involve cytoskeletal interactions as well as calcium-calcineurin signalling.

Mitochondrial DNA copy number, but not haplogroup, confers a genetic susceptibility to leprosy in Han Chinese from Southwest China

Background

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, an unculturable pathogen with an exceptionally eroded genome. The high level of inactivation of gene function in M. leprae, including many genes in its metabolic pathways, has led to a dependence on host energy production and nutritional products. We hypothesized that host cellular powerhouse - the mitochondria - may affect host susceptibility to M. leprae and the onset of clinical leprosy, and this may be reflected by mitochondrial DNA (mtDNA) background and mtDNA copy number.

Methods

We analyzed the mtDNA sequence variation of 534 leprosy patients and 850 matched controls from Yunnan Province and classified each subject by haplogroup. mtDNA copy number, taken to be proportional to mtDNA content, was measured in a subset of these subjects (296 patients and 231 controls) and 12 leprosy patients upon diagnosis.

Results

Comparison of matrilineal components of the case and control populations revealed no significant difference. However, measurement of mtDNA copy number showed that lepromatous leprosy patients had a significantly higher mtDNA content than controls (P = 0.008). Past medical treatments had no effect on the alteration of mtDNA copy number.

Conclusions

Our results suggested that mtDNA content, but not haplogroup, affects leprosy and this influence is limited to the clinical subtype of lepromatous leprosy.

Increased expression of regulatory T cells and down-regulatory molecules in lepromatous leprosy

T regulatory cells (Tregs) play an important role in the mechanism of host's failure to control pathogen dissemination in severe forms of different chronic granulomatous diseases, but their role in leprosy has not yet been elucidated; 28 newly diagnosed patients (16 patients with lepromatous leprosy and 12 patients with tuberculoid leprosy) and 6 healthy Mycobacterium leprae-exposed individuals (contacts) were studied. Tregs were quantified by flow cytometry (CD4+ CD25+ Foxp3+) in peripheral blood mononuclear cells stimulated in vitro with a M. leprae antigenic preparation and phytohemagglutinin as well as in skin lesions by immunohistochemistry. The lymphoproliferative (LPR), interleukin-10 (IL-10), and interferon-γ (IFN-γ) responses of the in vitro-stimulated peripheral blood mononuclear cells and the in situ expression of IL-10, transforming growth factor-β (TGF-β), and cytotoxic T-lymphocyte antigen 4 (CTLA-4) were also determined. We show that M. leprae antigens induced significantly lower LPR but significantly higher Treg numbers in lepromatous than tuberculoid patients and contacts. Mitogen-induced LPR and Treg frequencies were not significantly different among the three groups. Tregs were also more frequent in situ in lepromatous patients, and this finding was paralleled by increased expression of the antiinflammatory molecules IL-10 and CTLA-4 but not TGF-β. In lepromatous patients, Tregs were intermingled with vacuolized hystiocyte infiltrates all over the lesion, whereas in tuberculoid patients, Tregs were rare. Our results suggest that Tregs are present in increased numbers, and they may have a pathogenic role in leprosy patients harboring uncontrolled bacillary multiplication but not in those individuals capable of limiting M. leprae growth.

Crohn's disease and the mycobacterioses: a quarter century later. Causation or simple association?

It has been more than 25 years since Mycobacterium paratuberculosis was first proposed as an etiologic agent in Crohn's disease based on the isolation of this organism from several patients. Since that time, a great deal of information has been accumulated that clearly establishes an association between M. paratuberculosis and Crohn's disease. However, data are conflicting and difficult to interpret and the field has become divided into committed advocates and confirmed skeptics. This review is an attempt to provide a thorough and objective summary of current knowledge from both basic and clinical research from the views and interpretations of both the antagonists and proponents. The reader is left to draw his or her own conclusions related to the validity of the issues and claims made by the opposing views and data interpretations. Whether M. paratuberculosis is a causative agent in some cases or simply represents an incidental association remains a controversial topic, but current evidence suggests that the notion should not be so readily dismissed. Remaining questions that need to be addressed in defining the role of M. paratuberculosis in Crohn's disease and future implications are discussed.

Immunodiagnosis of tuberculosis: a dynamic view of biomarker discovery

Infection with Mycobacterium tuberculosis causes a variety of clinical conditions ranging from life-long asymptomatic infection to overt disease with increasingly severe tissue damage and a heavy bacillary burden. Immune biomarkers should follow the evolution of infection and disease because the host immune response is at the core of protection against disease and tissue damage in M. tuberculosis infection. Moreover, levels of immune markers are often affected by the antigen load. We review how the clinical spectrum of M. tuberculosis infection correlates with the evolution of granulomatous lesions and how granuloma structural changes are reflected in the peripheral circulation. We also discuss how antigen-specific, peripheral immune responses change during infection and how these changes are associated with the physiology of the tubercle bacillus. We propose that a dynamic approach to immune biomarker research should overcome the challenges of identifying those asymptomatic and symptomatic stages of infection that require antituberculosis treatment. Implementation of such a view requires longitudinal studies and a systems immunology approach leading to multianalyte assays.

Leprosy initially misdiagnosed as sarcoidosis, adult-onset still disease, or autoinflammatory disease

Leprosy is a chronic granulomatous disease caused by Mycobacterium leprae. We describe the case of a 20-year-old man from India living in Italy since 2003, who presented with erythematous papules and nodules distributed on his arms, legs, and face in 2006. He also had episodes of high fever, polyarthritis, and episcleritis. Sarcoidosis was suspected on the basis of elevated angiotensin-converting enzyme and bronchoalveolar lavage fluid, and the patient was treated with corticosteroids for about a year. A flare of the disease occurred each time corticosteroid was tapered or suspended. An autoinflammatory disease was then suspected and treated with immunosuppressant. Only the third deep skin biopsy revealed the presence of M. leprae. The lack of clinical suspicion and the unfamiliarity with the histology of leprosy delayed diagnosis and treatment. Leprosy should be considered in the differential diagnoses of patients presenting with rheumatic and cutaneous manifestations especially when they come from countries where the disease is endemic.

Genetic Diversity of Toll-Like Receptors and Immunity to M. leprae Infection

Genetic association studies of leprosy cohorts across the world have identified numerous polymorphisms which alter susceptibility and outcome to infection with Mycobacterium leprae. As expected, many of the polymorphisms reside within genes that encode components of the innate and adaptive immune system. Despite the preponderance of these studies, our understanding of the mechanisms that underlie these genetic associations remains sparse. Toll-like receptors (TLRs) have emerged as an essential family of innate immune pattern recognition receptors which play a pivotal role in host defense against microbes, including pathogenic strains of mycobacteria. This paper will highlight studies which have uncovered the association of specific TLR gene polymorphisms with leprosy or tuberculosis: two important diseases resulting from mycobacterial infection. This analysis will focus on the potential influence these polymorphic variants have on TLR expression and function and how altered TLR recognition or signaling may contribute to successful antimycobacterial immunity.

Genetic variants of the MRC1 gene and the IFNG gene are associated with leprosy in Han Chinese from Southwest China

Leprosy is an ancient infectious disease, with over 200,000 affected people (mainly in Asia and Africa) being registered annually. Genetic factors may confer susceptibility to this disease. In the present study, we genotyped 12 genetic variants of the MRC1 gene and the IFNG gene in 527 Han Chinese with leprosy and 583 healthy individuals from Yunnan, China, to discern potential association of these two genes with leprosy. In particular, we aimed to validate the recently reported association of MRC1 variant rs1926736 (p.G396S) and IFNG variant rs2430561 (+874 T>A) with leprosy, which were initially observed in Vietnamese and Brazilian populations, respectively. Our results failed to confirm the reported association between variants rs1926736 and rs2430561 and leprosy in Han Chinese. However, we found that variants rs692527 (P = 0.022) and rs34856358 (P = 0.022) of the MRC1 gene were associated with paucibacillary leprosy, and rs3138557 of the IFNG gene was significantly associated with multibacillary leprosy. The exact role of the MRC1 gene and the IFNG gene in leprosy awaits future study.

Human polymorphisms as clinical predictors in leprosy

Genetic and serum markers in human host can predict leprosy susceptibility per se as well as be useful in classification and/or prediction of clinical variants and immunological responses in leprosy. Adequate and timely assessment of potential risks associated with these 38 host leprosy genes could diminish epidemiological burden and improve life quality of patients with this still prevalent mycobacterial disease.

Interleukin 4-590T/C polymorphism and susceptibility to leprosy

BACKGROUND

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. Cell-mediated (Th1) immune response and humoral (Th2) immune response play different roles in leprosy infection. Interleukin 4 (IL-4) is a typical Th2 cytokine. It is a critical mediator of the Th1/Th2 balance.

OBJECTIVE

The objective of this study is to investigate the association between IL-4 gene -590T/C polymorphism and the susceptibility to leprosy in a Chinese population.

METHODS

The IL-4 variant -590T/C was detected by polymerase chain reaction-restriction fragment length polymorphism in 432 leprosy cases and 465 age-matched healthy controls. Data were analyzed using the chi-square test.

RESULTS

Frequencies of the IL-4-590TC and CC genotypes and the -590C allele were significantly lower in patients with leprosy than in healthy controls (odds ratio [OR]=0.74, 95% confidence interval [CI] 0.55-0.99, p=0.044; OR=0.46, 95% CI 0.25-0.84, p=0.010; and OR=0.68, 95% CI 0.54-0.86, p=0.001, respectively).

CONCLUSIONS

Our data suggest that the -590T/C polymorphism of the IL-4 gene is associated with decreased susceptibility of leprosy.