Leprosy, a neglected disease that causes a wide variety of clinical conditions in tropical countries

Neglected Tropical Diseases and Female Infertility: Possible Pathophysiological Mechanisms

Battling female infertility has posed a global challenge, where neglected tropical diseases (NTDs) are nonetheless a notable contributing factor. NTDs affect a variety of diseases, often of a chronic nature, which are often cited as some of the most lethal diseases operating against the most economically disadvantaged populations across the globe. The various causative agents for NTDs have been documented and could originate from a myriad of sources-from bacteria, fungi and viruses to ecto- and endoparasitic species-including but not limited to helminths and protozoa. This paper will seek to describe how NTDs influence female reproductive health, together with likely mediators. While these diseases have curable forms, their effects have gone well beyond female infertility, to major pain, disability and even mortality, particularly in poorer countries, thus causing economic hardship, reduced productivity and a pool of social stigma. NTDs adversely affect female reproductive functions through multiple mechanisms, including ROS-sensitive signalling, depression of steroidogenic markers and promotion of apoptosis. The effects also may reflect their influence on ovarian histomorphology, consequently resulting in female infertility. Current-directed studies, however, suggest a potential benefit in combining drugs for the most common NTDs as a deterrent to possible female infertility endowed by NTD infection. Nonetheless, further clinical investigations will be instrumental in elucidating the probable preventive value of combination drugs as adjuvant therapy to NTDs infections. This will provide comprehensive insight into the pathophysiological and molecular basis for the impairment of female fertility brought about by NTDs, leading to the development of preventive models to curb the adverse effects of NTDs on female reproductive health. Therefore, attention should be given to providing the right, timely and effective mode of treatment for NTDs-related female infertility.

Analysis of misdiagnosed or delayed-diagnosed Leprosy bacillus infection from 1990 to 2020 with a prophet time series prediction in Hubei Province, China

To analyze the misdiagnosis or delayed diagnosis of leprosy in Hubei Province, China during the past 30 years, which can provide a scientific basis for improving the prevention and treatment of leprosy by proposing targeted intervention measures. A retrospective study was conducted to compile 161 cases of misdiagnosed or delayed diagnosis of leprosy in Hubei Province during 1990 to 2020 from the National Leprosy Prevention and Control Management Information System and the background information of regional leprosy control centers in Hubei Province. Among 161 study subjects, the shortest delay period was 25.30 months for cases aged 15 to 20 years, the longest delay period was 67.09 months for cases aged 51 to 60 years, the shortest delay period was 35.33 months for type TN cases, and the longest delay period was 75.17 months for type I cases. There were 71 cases (44.10%) misdiagnosed, and the top 5 misdiagnosed disease names were rash 23 cases (32.39%). Top 5 misdiagnosed cases were rash 23 (32.39%), rheumatism 10 (14.08%), skin ulceration 9 (12.68%), dermatitis 9 (12.68%), neuritis 9 (12.68%). In the prophet prediction, the overall trend of leprosy misdiagnosis was increasing and within 1 year the number is fluctuant. The training of medical personnel at all levels on leprosy prevention and treatment should be strengthened, and the public awareness of leprosy prevention and treatment should be enhanced.

Economic evaluation of a leprosy innovation project in Northern Nigeria: cost-effectiveness analysis

Background

The state of leprosy in Nigeria and the realities of post elimination era underscore the need for evidence- based cost-effective approach to early case detection for enhanced control and elimination of leprosy. This study evaluated the operational cost-effectiveness of a community delivered Legacy Innovative Project implemented to enhance leprosy case detection in northern Nigeria.

Methods

Data were collected from an explorative cross-sectional study, undertaken in a practice setting among endemic communities in three states in northern Nigeria. Primary and secondary data were collected from the project, routine records and programme annual reports. Costs and effects were measured from both providers’ and patients’ perspectives, and outcome expressed as cost per new case detected. Incremental estimates of costs and effects of the project compared to routine practice were used to obtain the cost-effectiveness result, as incremental cost-effectiveness ratio (ICER). All costs were converted to the US Dollar at 2018exchange rate (N350 = US$1.00). Univariate sensitivity analysis was performed to evaluate uncertainties around the ICER.

Results

The Project overall detected a total of 347 newly confirmed leprosy cases at a total annual cost of US$49,337.19, averaging US$142.18 per new case detected. Key cost drivers included routine meetings, which accounted for 28% of total expenditure, while Social Mobilization and Training/Workshop accounted for17% respectively. Findings were similar across the states. Overall, the Project dominated routine practice with ICER of US$(-17.73) per additional/new case detected, as a very cost-effective strategy. Sensitivity analysis reinforced the cost-effectiveness result.

Conclusions

The Legacy Innovative Project demonstrated a more efficient and cost-saving approach to leprosy case detection. Findings present important information to policy and programmes for enhanced control and elimination of leprosy in related settings.

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Interleukin-17A in Egyptian leprosy patients: A clinical, genetic, and biochemical study

Background

Leprosy represents a long-term communicable disease resulting from Mycobacterium leprae infection. IL-17A is one of the pro-inflammatory cytokines that protects humans against many fungal and bacterial pathogens.

Objective

To investigate IL-17A (rs2275913) gene polymorphism and its circulating level in leprosy patients, and to correlate the detected results with different clinical aspects of leprosy in the investigated patients.

Methods

60 patients with leprosy, and 29 age and sex-matched volunteers were investigated for IL-17A serum level and IL-17A single nucleotide polymorphism (SNP) by ELISA and RFLP-PCR respectively.

Results

IL-17A serum level was significantly higher in leprosy patients than in controls (p = 0.034), and in TL than LL (p = 0.017). IL-17A (rs2275913 A/G) G allele and GG genotype were associated significantly with LL (p = 0.005and 0.001 respectively). IL-17A (rs2275913 A/G) AG genotype carriers demonstrated the highest IL-17A serum levels; however, its lowest levels were found in IL-17A (rs2275913 A/G) AA genotype carriers (p = 0.005). Grade 2 disability (p = 0.030) and positive slit skin smear (SSS) (p = 0.005) were significantly associated with IL-17A (rs2275913 A/G) GG genotype.

Study limitations

The small number of studied subjects.

Conclusions

IL -17A may have a pivotal role in leprosy pathogenesis. IL-17A (rs2275913) GG genotype plus G allele might be related to the development of LL in the Egyptian population.

Algorithm design for a cytokine release assay of antigen-specific in vitro stimuli of circulating leukocytes to classify leprosy patients and household contacts

Background

Immunological biomarkers have often been used as a complementary approach to support clinical diagnosis in several infectious diseases. The lack of commercially available laboratory tests for conclusive early diagnosis of leprosy has motivated the search for novel methods for accurate diagnosis. In the present study, we describe an integrated analysis of a cytokine release assay using a machine learning approach to create a decision tree algorithm. This algorithm was used to classify leprosy clinical forms and monitor household contacts.

Methods

A model of Mycobacterium leprae antigen-specific in vitro assay with subsequent cytokine measurements by enzyme-linked immunosorbent assay was employed to measure the levels of tumor necrosis factor (TNF), interferon-γ, interleukin 4, and interleukin 10 (IL-10) in culture supernatants of peripheral blood mononuclear cells from patients with leprosy, healthy controls, and household contacts. Receiver operating characteristic curve analysis was carried out to define each cytokine’s global accuracy and performance indices to identify clinical subgroups.

Results

Data demonstrated that TNF (control culture [CC]: AUC = 0.72; antigen-stimulated culture [Ml]: AUC = 0.80) and IL-10 (CC: AUC = 0.77; Ml: AUC = 0.71) were the most accurate biomarkers to classify subgroups of household contacts and patients with leprosy, respectively. Decision tree classifier algorithms for TNF analysis categorized subgroups of household contacts according to the operational classification with moderate accuracy (CC: 79% [48/61]; Ml: 84% [51/61]). Additionally, IL-10 analysis categorized leprosy patients’ subgroups with moderate accuracy (CC: 73% [22/30] and Ml: 70% [21/30]).

Conclusions

Together, our findings demonstrated that a cytokine release assay is a promising method to complement clinical diagnosis, ultimately contributing to effective control of the disease.

Loop-mediated isothermal amplification (LAMP) assay targeting RLEP for detection of Mycobacterium leprae in leprosy patients

OBJECTIVE

Leprosy is a chronic infectious disease caused by Mycobacterium leprae and it remains a significant health problem in several parts of the world. Early and accurate diagnosis of this disease is therefore essential. Previously published loop-mediated isothermal amplification (LAMP) protocols for detecting mycobacterial species used conventional primers targeting the 16S rRNA, gyrB and insertion sequence genes.

METHODS

In this study, we conducted a LAMP assay for leprosy and compared it with quantitative polymerase chain reaction (q-PCR) and conventional PCR assays to determine the efficiency, sensitivity and specificity of each technique. We chose conserved sequence RLEP as a suitable molecular target for assays.

RESULTS

The LAMP assay provided rapid and accurate results, confirming leprosy in 91/110 clinical skin tissue samples from leprosy patients and amplifying the target pathogen in <60 min at 65 °C. The assay was more sensitive than conventional PCR and more straightforward and faster than the q-PCR assay.

CONCLUSIONS

The LAMP assay has the potential for developing quicker, more accessible visual methods for the detection of M. leprae, which will enable early diagnosis and treatment and prevent further infection in endemic areas.

Presence of Senescent and Memory CD8+ Leukocytes as Immunocenescence Markers in Skin Lesions of Elderly Leprosy Patients

Leprosy is an infectious disease that remains endemic in approximately 100 developing countries, where about 200,000 new cases are diagnosed each year. Moreover, multibacillary leprosy, the most contagious form of the disease, has been detected at continuously higher rates among Brazilian elderly people. Due to the so-called immunosenescence, characterized by several alterations in the quality of the immune response during aging, this group is more susceptible to infectious diseases. In view of such data, the purpose of our work was to investigate if age-related alterations in the immune response could influence the pathogenesis of leprosy. As such, we studied 87 individuals, 62 newly diagnosed and untreated leprosy patients distributed according to the age range and to the clinical forms of the disease and 25 healthy volunteers, who were studied as controls. The frequency of senescent and memory CD8⁺ leukocytes was assessed by immunofluorescence of biopsies from cutaneous lesions, while the serum levels of IgG anti-CMV antibodies were analyzed by chemiluminescence and the gene expression of T cell receptors' inhibitors by RT-qPCR. We noted an accumulation of memory CD8⁺ T lymphocytes, as well as reduced CD8⁺CD28⁺ cell expression in skin lesions from elderly patients, when compared to younger people. Alterations in LAG3 and PDCD1 gene expression in cutaneous lesions of young MB patients were also observed, when compared to elderly patients. Such data suggest that the age-related alterations of T lymphocyte subsets can facilitate the onset of leprosy in elderly patients, not to mention other chronic inflammatory diseases.

Study of TNF-α, IFN-γ, TGF-β, IL-6, and IL-10 Gene Polymorphism in Individuals from the Leprosy-Endemic Area in the Brazilian Amazon

This study aimed at verifying the relationship between the polymorphisms of the cytokines tumor necrosis factor-alpha (TNF-α) -308 G → A (rs1800629); interferon gamma (IFN-γ) +874 T → A (rs2430561); transforming growth factor-beta (TGF-β) códon 10 (rs1982073) and códon 25 (rs1800471); interleukin (IL)-6 - 174 G → C (rs180079) and IL-10 - 1082 A→T (rs1800896); -819 C → T (rs1800871); -592 A→C (rs1800872); and leprosy. Blood samples were analyzed from 106 individuals, of whom 24 were paucibacillary (PB), 28 were multibacillary (MB), and 54 were patient contacts. Analysis of cytokine polymorphisms was typified by the polymerase chain reaction technique. For TGF-β +869 T → C and +915 G→C, a tendency to associate the presence of the C allele at codon 10 with leprosy was demonstrated, with the T allele being most frequently found in the CCOSI (P = 0.056). For the polymorphisms IL-10 - 1082 A→T, -819 C→T, and -592 A→C, we found an association of the GCC/GCC genotype with the susceptibility to the disease and the A allele at position 1082 with the leprosy protection. Greater predominance was found of ACC/ATA (31.3%) and GCC/ATA (37.5%) (P = 0.03) and the A allele at position -1082 (76.85%) (P = 0.043) in the CCOSI groups, whereas the GCC/GCC was found in the MB group (22.2%) (P = 0.05). For the other cytokines's single-nucleotide polymorphisms, there were no associations with susceptibility to leprosy. These results are limited by sample size, may not be conclusive, and will need further confirmation in a larger cohort.

Diagnostic value of neutrophil-to-lymphocyte ratio in patients with leprosy reactions

INTRODUCTION

Leprosy reactions, classified as type 1 and type 2 reactions, are acute clinical conditions of exacerbation of localized or systemic inflammatory response inpatients with leprosy. No laboratory biomarker is available to predict the emergence of these reactions. Neutrophil-to-lymphocyte ratio (NLR) is an accurate biomarker for diagnosis and prognosis of various inflammatory and neoplastic diseases.

OBJECTIVE

This study aimed to investigate the accuracy of the NLR in the diagnosis of leprosy reactions.

MATERIALS AND METHODS

NLR was calculated for all patients and a receiver operating characteristic curve (ROC) were generated to identify the NLR cut-off point.

RESULTS

A total of 123 patients with leprosy were included, 98 with leprosy reactions of which 56 (45.5%) had type 1 and 42 (34.1%) with type 2. Mean NLR was higher among patients with reactions than among those without. It was also statistically higher among patients with type 2 reactions than in those with type 1 reactions. Receiver operating characteristic curves were generated to identify the NLR cut-off point. The area under the ROC curve was 0.794 for diagnosis of any leprosy reaction and 0.796 for the diagnosis of type 2 reaction. The NLR cut-off points for diagnosis of any leprosy reaction and for type 2 reaction were 2.75 (sensitivity 61.0%, specificity 92.0%, accuracy 77.0%) and 2.95 (sensitivity 81.0%, specificity 74.0%, accuracy 78.0%), respectively.

CONCLUSION

These results suggest that NLR could be a potential biomarker for diagnosis of leprosy reaction and useful for discriminating patients with type 2 reactions from those with type 1 leprosy reactions.

Langerin (CD207)-positive cells in leprosy: Possible implications for pathogenesis of the disease with special emphasis on dermal immunoreactivity

Leprosy is a disease caused by Mycobacterium leprae, which is characterized by two distinct poles, the tuberculoid pole and the lepromatous pole, depending on the immune response to the bacillus. Langerin-positive cells are dendritic cells that appear to play an essential role in the development of the disease. These cells are specialized in the processing and presentation of antigens, exerting an important function in the activation of the immune system. To evaluate the expression of langerin-positive cells (CD207+) in skin lesion fragments of patients with a diagnosis of M. leprae infection and to associate the expression of these cells with the polar forms of the disease. Langerin-positive cells were detected in larger numbers in lesions of patients with the tuberculoid form compared to those with the lepromatous form. The presence of a larger number of these cells in patients with the tuberculoid form suggests an important participation of langerin-positive cells, capturing antigens and favoring an effective immune response to infection with M. leprae.

Mycobacterium leprae-induced nerve damage: direct and indirect mechanisms

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. This disease is characterized by skin and peripheral nerve trunk damage. The mechanisms responsible for the observed nerve damage in leprosy could be directly related to the ability of M. leprae to infect Schwann cells, leading to triggering of signaling events. Therefore, we hypothesize that in response to M. leprae infection, activation of the Notch signaling pathway in Schwann cells could play a crucial role in glial cell dedifferentiation. On the other hand, nerve damage evidenced in this disease may be additionally explained by indirect mechanisms such as the immune response and genetic susceptibility of the host. The understanding of the mechanisms leading to nerve damage induced by M. leprae infection will allow us to generate valuable tools for the early detection of leprosy as well as for the mitigation of the effects of this disabling disease.

The oral cavity in leprosy: what clinicians need to know

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, a bacillus that has a tropism for skin and peripheral nerves. Leprosy treatment is based on a multidrug therapy established by the World Health Organization in 1982 and, despite its widespread use, Brazil ranks second worldwide in numbers of cases. Oral involvement in leprosy has been poorly described in the literature, and few studies have shown that although the bacillus is found in mucosa, specific leprosy lesions are rare and affect patients with advanced stages of the disease. This review aimed to assess the literature on oral manifestations in leprosy and the aspects involving oral cavity in leprosy pathogenesis.

Langerhans cells (CD1a and CD207), dermal dendrocytes (FXIIIa) and plasmacytoid dendritic cells (CD123) in skin lesions of leprosy patients

The clinical course of infection with Mycobacterium leprae varies widely and depends on the pattern of the host immune response. Dendritic cells play an important role in the activation of the innate and adaptive immune system and seem to be essential for the development of the disease. To analyze the presence of epidermal dendritic cells (CD1a and CD207), plasmacytoid dendritic cells (CD123) and dermal dendrocytes (factor XIIIa) in lesion fragments of leprosy patients, skin samples from 30 patients were studied. These samples were submitted to immunohistochemistry against CD1a, CD207, FXIIIa, and CD123. The results showed a larger number of Langerhans cells, detected with the CD1a or CD207 marker, dermal dendrocytes and plasmacytoid dendritic cells in patients with the tuberculoid form. A positive correlation was observed between the Langerhans cell markers CD1a and CD207 in both the tuberculoid and lepromatous forms, and between Langerhans cells and dermal dendrocytes in samples with the tuberculoid form. The present results indicate the existence of a larger number of dendritic cells in patients at the resistant pole of the disease (tuberculoid) and suggest that the different dendritic cells studied play a role, favoring an efficient immune response against infection with M. leprae.

Genome-Wide Screening of mRNA Expression in Leprosy Patients

Leprosy, an infectious disease caused by Mycobacterium leprae, affects millions of people worldwide. However, little is known regarding its molecular pathophysiological mechanisms. In this study, a comprehensive assessment of human mRNA was performed on leprosy skin lesions by using DNA chip microarrays, which included the entire spectrum of the disease along with its reactional states. Sixty-six samples from leprotic lesions (10TT, 10BT, 10BB, 10BL, 4LL, 14R1, and 10R2) and nine skin biopsies from healthy individuals were used as controls (CC) (ages ranged from 06 to 83 years, 48 were male and 29 female). The evaluation identified 1580 differentially expressed mRNAs [Fold Change (FC) ≥ 2.0, p ≤ 0.05] in diseased lesions vs. healthy controls. Some of these genes were observed in all forms of the disease (CD2, CD27, chit1, FA2H, FAM26F, GZMB, MMP9, SLAMF7, UBD) and others were exclusive to reactional forms (Type "1" reaction: GPNMB, IL1B, MICAL2, FOXQ1; Type "2" reaction: AKR1B10, FAM180B, FOXQ1, NNMT, NR1D1, PTX3, TNFRSF25). In literature, these mRNAs have been associated with numerous pathophysiological processes and signaling pathways and are present in a large number of diseases. The role of these mRNAs maybe studied in the context of developing new diagnostic markers and therapeutic targets for leprosy.

Influence of Genetic Ancestry on INDEL Markers of NFKβ1, CASP8, PAR1, IL4 and CYP19A1 Genes in Leprosy Patients

BACKGROUND

Leprosy is an insidious infectious disease caused by the obligate intracellular bacteria Mycobacterium leprae, and host genetic factors can modulate the immune response and generate distinct categories of leprosy susceptibility that are also influenced by genetic ancestry.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated the possible effects of CYP19A1 [rs11575899], NFKβ1 [rs28362491], IL1α [rs3783553], CASP8 [rs3834129], UGT1A1 [rs8175347], PAR1 [rs11267092], CYP2E1 [INDEL 96pb] and IL4 [rs79071878] genes in a group of 141 leprosy patients and 180 healthy individuals. The INDELs were typed by PCR Multiplex in ABI PRISM 3130 and analyzed with GeneMapper ID v3.2. The NFKβ1, CASP8, PAR1 and IL4 INDELs were associated with leprosy susceptibility, while NFKβ1, CASP8, PAR1 and CYP19A1 were associated with the MB (Multibacilary) clinical form of leprosy.

CONCLUSIONS/SIGNIFICANCE

NFKβ1 [rs28362491], CASP8 [rs3834129], PAR1 [rs11267092] and IL4 [rs79071878] genes are potential markers for susceptibility to leprosy development, while the INDELs in NFKβ1, CASP8, PAR1 and CYP19A1 (rs11575899) are potential markers for the severe clinical form MB. Moreover, all of these markers are influenced by genetic ancestry, and European contribution increases the risk to leprosy development, in other hand an increase in African contribution generates protection against leprosy.

Diffuse leprosy with "deck-chair" sign

A 55-year-old male presented with asymptomatic extensive skin lesions since one year. He was found to have diffuse lesions involving the face, trunk, arms, and thighs along with symmetric peripheral nerve thickening. Bacteriological and histopathological examination confirmed lepromatous leprosy. There was a conspicuous sparing of the abdominal creases and axillae from the infiltrative lesions suggesting a positive “deck-chair” sign. This sign has been described in the past with papulo-erythroderma of Ofuji and certain other disorders. Leprosy may be now included among the causes of “deck-chair” sign.

Application of RLEP real-time PCR for detection of M. leprae DNA in paraffin-embedded skin biopsy specimens for diagnosis of paucibacillary leprosy

The TaqMan real-time polymerase chain reaction (PCR) assay was evaluated systematically with respect to the standard curve, linear range, and used for detecting Mycobacterium leprae DNA in paraffin-embedded skin biopsy specimens from 60 confirmed leprosy patients and three healthy individuals and 29 other dermatoses and bacterial DNA from 21 different species. The test was further evaluated with 51 paucibacillary (PB) patients. The results showed that the test had good sensitivity (8 fg) and good specificity with no cross-reactivity with 21 other bacterial species and the control specimens, except one with Xanthomatosis. The real-time PCR detection rate for the 51 PB specimens was 74.5% (38 of 51). We conclude that the real-time PCR test is a useful adjunct test for diagnosing early stage or PB leprosy cases.