Unveiling the role of NK cells, NKT-like cells, and γδ cells in pathogenesis of type 1 reactions in leprosy

Leprosy is a disease with spectral clinical manifestations along with two types of reactions, type 1 reaction (T1R) and type 2 reaction (T2R). T1R especially occurs because of the defensive upgradation of cell-mediated immunity (CMI) to M. leprae antigens. T1R is the main cause of disability in leprosy. The role of conventional adaptive T cells has been well studied to understand T1R. A comprehensive understanding of the role of unconventional T cells in the manifestation of inflammation during T1R is crucial and has not been studied. In our study, we found significantly higher plasma levels of TNFα, IL1β, IL17, and IP10 in T1R when compared to non-reaction (NR). Gene expression for cytokines in blood circulation by qPCR showed significantly higher expression of IFNγ, IP10, TNFα, IL6, IL17A and chemokines CCL3, CCR1, CCR5, and CXCR3 in T1R as compared to NR. Frequencies of NKT-like cells (48.7 %) and NK cells (22.3 %) were found significantly higher in T1R in comparison to NR (36.9 %, 18.3 %, respectively) (p = 0.0001). Significantly lower levels of γδT cells (3.32 %) were observed in T1R in comparison to NR (5.16 %). The present study has provided evidence for the first time on the role of plausible unconventional T cells in the immunopathogenesis of T1R in leprosy.

Genomic characterization of Mycobacterium lepromatosis from ENL patients from India

BACKGROUND

Leprosy is caused by Mycobacterium leprae and Mycobacterium lepromatosis. Both organisms cannot be cultured in vitro. M. lepromatosis was found to be associated mainly with diffuse lepromatous leprosy and with Lucio's phenomena initially. Later, M. lepromatosis was observed in borderline leprosy cases (BL), lepromatous leprosy cases (LL) and leprosy reactional cases (T1R and ENL). Although many cases are being reported with similar clinical features like Lucio phenomenon in India but M. lepromatosis was not isolated from these cases. The aim of this study was to screen MB patients and patients with type 2 reaction for the presence of M. lepromatosis.

METHODOLOGY

We recruited a total of 75 multibacillary leprosy cases (45 MB cases without reaction and 30 type 2 reaction (ENL) cases) from TLM hospitals Purulia (West Bengal), Barabanki (Uttar Pradesh), Shahdara (Delhi) and PGIMER (Chandigarh), India. Punch biopsies of 5 mm were collected in 70% ethanol from all the study subjects. DNA was extracted followed by Hemi-nested PCR targeting 16S rRNA gene specific for M. lepromatosis. Further, PCR products were processed for Sanger sequencing for an absolute confirmation of M. lepromatosis. Whole genome sequencing was done to confirm the presence of M. lepromatosis.

RESULT

We observed presence of M. lepromatosis in 4 necrotic ENL patients by heminested PCR. There was 100% 16S rRNA sequence similarity with M. lepromatosis FJ924 in one case, 98.96% in two cases and in one case it was 90.9% similarity by nucleotide BLAST (BLASTn) by using the NCBI website. On the basis of Sanger sequencing, we noted presence of M. lepromatosis in 3 necrotic ENL patients as one sample only gave 90.9% similarity by BLASTn. On the basis of de novo assembly and genome obtained, only one sample S4 with a 2.9 mb genome size was qualified for downstream analysis. Sixteen M. lepromatosis- specific proteins were identified in this case and the closest species was M. lepromatosis strain FJ924 based on whole genome level phylogeny.

CONCLUSION

These results provide valuable insights into the prevalence of M. lepromatosis in ENL patients in different regions of India and contribute to our understanding of the genetic characteristics of this pathogen in the context of leprosy.

Efficacy of fixed duration multidrug therapy for the treatment of multibacillary leprosy: A prospective observational study from Northern India

BACKGROUND

In endemic regions of several countries, the prevalence of leprosy has not come down to the level of elimination. On the contrary, new cases are being detected in large numbers. Clinically, it is frequently noted that despite completion of multibacillary multidrug therapy for 12 months, the lesions remain active, especially in cases with high bacteriological indices.

AIM

The present study focused on finding out the viable number of Mycobacterium leprae during the 12-month regimen of multibacillary multidrug therapy, at six and 12 months intervals and, attempting to determine their role in disease transmission.

METHODS

Seventy eight cases of multibacillary leprosy cases were recruited from leprosy patients registered at The Leprosy Mission hospitals at Shahdara (Delhi), Naini (Uttar Pradesh) and Champa (Chhattisgarh), respectively. Slit skin smears were collected from these patients which were transported to the laboratory for further processing. Ribonucleic acid was extracted by TRIzol method. Total Ribonucleic acid was used for real-time reverse transcription-polymerase chain reaction (two-step reactions). A standard sample with a known copy number was run along with unknown samples for a reverse transcription-polymerase chain reaction. Patients were further assessed for their clinical and molecular parameters during 6th month and 12th month of therapy.

RESULTS

All 78 new cases showed the presence of a viable load of bacilli at the time of recruitment, but we were able to follow up only on 36 of these patients for one year. Among these, using three different genes, 20/36 for esxA, 22/36 for hsp18 and 24/36 for 16S rRNA cases showed viability of M. leprae at the time of completion of 12 months of multidrug therapy treatment. All these positive patients were histopathologically active and had bacillary indexes ranging between 3+ and 4+. Patients with a high copy number of the Mycobacterium leprae gene, even after completion of treatment as per WHO recommended fixed-dose multidrug therapy, indicated the presence of live bacilli.

LIMITATIONS

Follow up for one year was difficult, especially in Delhi because of the migratory nature of the population. Patients who defaulted for scheduled sampling were not included in the study.

CONCLUSION

The presence of a viable load of bacilli even after completion of therapy may be one of the reasons for relapse and continued transmission of leprosy in the community.

Existence of viable Mycobacterium leprae in natural environment and its genetic profiling in a leprosy endemic region

Introduction

Molecular epidemiology of leprosy is very important to study leprosy transmission dynamics and to enhance our understanding of leprosy in endemic areas by utilizing the molecular typing method. Nowadays our understanding of leprosy transmission dynamics has been refined by SNP typing and VNTR marker analysis of M. leprae strains.

Objective

This study was carried out to find out the presence of viable M. leprae in the soil and water samples from residing areas of leprosy patients staying in different blocks of Purulia district of West Bengal, understanding their genotypes and compared with that of M. leprae present in patients.

Material and methods

Slit-skin smear (SSS) samples (n=112) were collected from the active multibacillary leprosy patients from different blocks of leprosy endemic area. Soil samples (n=1060) and water samples (n=620) were collected from residing areas of leprosy patients. SNP subtyping was performed by PCR followed by sequencing. Multiplex PCR was performed using fifteen ML-VNTR loci and results were analysed.

Results

We observed high PCR positivity in soil samples (344 out of 1060; 32%) and water samples (140 out of 620; 23%). These PCR positive samples when further screened for viability, it was observed that 150 soil samples (44%) and 56 water samples (40%) showed presence of 16S rRNA. SNP typing of M. leprae revealed presence of predominantly type 1. SNP subtype 1D (83%) was most prevalent in all the blocks of Purulia followed by subtype 1C (15%) and subtype 1A (2%). SNP subtype 2F was noted in only one sample. SNP and VNTR combination showed presence of similar strain type in certain pockets of Purulia region which was responsible for transmission.

Conclusion

Presence of viable M. leprae in the environment, and presence of SNP Type 1 M. leprae in patients and environment suggests both environment and patients play a role in disease transmission.

Ofloxacin resistance in multibacillary new leprosy cases from Purulia, West Bengal: A threat to effective secondary line treatment for rifampicin resistant leprosy cases

OBJECTIVE

Purulia is one of the high endemic districts for leprosy in West Bengal [Eastern part of India]. The annual new case detection rate (ANCDR) of leprosy in West Bengal is 6.04/100000 (DGHS 2019-20). Our earlier report has already provided the evidence of presence of secondary drug resistance in relapse cases of leprosy. The primary aim of the study was to find out primary drug resistance pattern for dapsone, rifampicin and ofloxacin among new leprosy patients from Purulia, West Bengal. to find out the emergence of primary drug resistance to any of these drugs.

METHODS

In the present study, slit- skin smear samples were collected from 145 newly diagnosed leprosy cases from TLM Purulia hospital during the duration between 2017-2018. DNA was extracted from these samples and were analyzed for the genes associated with drug resistance in M. leprae genome by PCR and was followed by Sanger sequencing. Wild-type strain (Thai-53) and mouse footpad-derived drug-resistant (Z-4) strain was used as reference strains.

RESULTS

Out of 145 cases; 25 cases had shown mutation in any of the three genes of rpoB, folP and gyrA associated with rifampicin, dapsone and ofloxacin resistance as described by WHO respectively by Sanger sequencing. Among these 25 cases; 16 cases had shown the mutations in ofloxacin, 2 cases had shown the mutation in combination of ofloxacin and rifampicin, 4 cases had shown the mutation only in rifampicin, 1 case had shown mutation in combination of rifampicin and dapsone and 2 cases had shown mutation only in dapsone.

DISCUSSION AND CONCLUSION

Results from this study indicated the emergence of resistance to anti-leprosy drugs in new cases of leprosy. As ofloxacin is the alternate drug for the treatment of rifampicin resistant cases, the emergence of new cases with resistance to ofloxacin indicates that ofloxacin resistant M. leprae strains are actively circulating in endemic region i. e. Purulia, West Bengal of India and poses a concern about the effective treatment of rifampicin resistance cases.

Real-time PCR-based quantitation of viable Mycobacterium leprae strain from clinical samples and environmental sources and its genotype in multi-case leprosy families of India

The potential role of environmental M. leprae in the transmission of leprosy remains unknown. We investigated role of environment as a possible source of viable M. leprae responsible for transmission of leprosy. The samples were collected from 10 multi-case leprosy families comprising, slit skin smear (SSS) from 9 multibacillary (MB), 16 paucibacillary cases (PB), 22 household contacts, and 38 environmental soil samples. The quantum of viable M. leprae was estimated by qRT-PCR using 16S rRNA gene from soil and SSS. Genotypes of M. leprae were determined by gene sequencing. We could observe presence of viable M. leprae in 11 (44%) leprosy cases (M. leprae 16S rRNA gene copies range from 1.78 × 10² to 8.782 × 10⁹) and 4 (18%) household contacts (M. leprae 16S rRNA gene copies range from 2.54 × 10³ and 7.47 × 10⁴). Remarkably, presence of viable M. leprae was also noted in 10 (53%) soil samples where in M. leprae 16S rRNA gene copies ranged from 4.36 × 10² to 7.68 × 10². M leprae subtype 1D was noted in most of the leprosy cases their household contacts and in the surrounding soil samples indicating source of infection in household contacts could be from environment or patients. M. leprae 16S rRNA copies were approximately similar in both PB cases and soil samples along with presence of SNP type 1 subtype 1D in both samples indicating source of M. leprae from patients to contacts was either from patients or environment or both.

Detection of Mycobacterium lepromatosis in patients with leprosy in India

Introduction

The most commonly noted reactions in leprosy patients are type 1 reactions and erythema nodosum leprosum, with some rare phenomenon of host response known as Lucio phenomenon or leprosy of Lucio and Latapi which is caused by Mycobacterium lepromatosis. So far, no case of M. lepromatosis has been reported from India.

Materials and methods

The main objective of this study was to detect any positive cases of M. lepromatosis in India with such a complication. We screened slit skin smear/biopsy samples from lepromatous leprosy (LL) patients reporting to The Leprosy Mission Community Hospitals across the country. Eighty-eight slit skin smears were collected from leprosy patients in 70% ethanol. DNA was extracted from all these samples. Polymerase chain reaction (PCR) was done for 2 genes; one set was for 16S rRNA and the other set was for coproporphyrinogen III oxidase (hemN) gene. Then, sequencing was done for all positive amplicons. Homology of the sequences was analyzed using the Basic Local Alignment Search Tool at the National Center of Biotechnology Information database.

Results

Among 88 isolates, we found 4 positive cases for M. lepromatosis. All 4 were LL cases with a bacteriological index ranging from 2+ to 4+. On the basis of the National Center of Biotechnology Information Basic Local Alignment Search Tool analysis, the sequenced amplicons of both genes matched with the M. lepromatosis 16S rRNA and phosphofructokinase genes but not with hemN gene of lepromatosis. This is the first report for the presence of M. lepromatosis in LL cases from India.

Conclusion

This new species M. lepromatosis exists beyond Mexico, Singapore and it is the cause of DLL in India also. It may cause dual infections along with M. leprae in endemic areas like India.

Enriched whole genome sequencing identified compensatory mutations in the RNA polymerase gene of rifampicin-resistant Mycobacterium leprae strains

Despite more than three decades of multidrug therapy (MDT), leprosy remains a major public health issue in several endemic countries, including India. The emergence of drug resistance in Mycobacterium leprae (M. leprae) is a cause of concern and poses a threat to the leprosy-control program, which might ultimately dampen the achievement of the elimination program of the country. Rifampicin resistance in clinical strains of M. leprae are supposed to arise from harboring bacterial strains with mutations in the 81-bp rifampicin resistance determining region (RRDR) of the rpoB gene. However, complete dynamics of rifampicin resistance are not explained only by this mutation in leprosy strains. To understand the role of other compensatory mutations and transmission dynamics of drug-resistant leprosy, a genome-wide sequencing of 11 M. leprae strains - comprising five rifampicin-resistant strains, five sensitive strains, and one reference strain - was done in this study. We observed the presence of compensatory mutations in two rifampicin-resistant strains in rpoC and mmpL7 genes, along with rpoB, that may additionally be responsible for conferring resistance in those strains. Our findings support the role for compensatory mutation(s) in RNA polymerase gene(s), resulting in rifampicin resistance in relapsed leprosy patients.

Presence of viable Mycobacterium leprae in environmental specimens around houses of leprosy patients

PURPOSE

Leprosy is a chronic systemic infectious disease caused by Mycobacterium leprae, one of the first organisms to be established as the cause for disease in humans. Because of high prevalence pockets of leprosy in the endemic regions, it is necessary to identify the possible sources of M. leprae in the environment and its mode of transmission.

MATERIALS AND METHODS

Slit skin smears (SSSs) from lesions were collected in 70% ethanol from 50 leprosy cases staying in the leprosy resettlement village and hospital from a high endemic area. One hundred and sixty soil samples were collected from different areas around the leprosy hospital and from the resettlement village of cured leprosy patients where active cases also resided at the time of sample collection. M. leprae specific gene region (RLEP 129 bp) and 16S rRNA targets were used for polymerase chain reaction (PCR) based detection for the presence and viability of M. leprae. An rpoT region was also amplified to determine presence of numbers of 6 bp tandem repeats.

RESULTS

All the SSS samples collected from patients showed three copies of rpoT region (6 bp tandem repeat, an ancient Indian type). Fifty-two soil samples showed presence of M. leprae DNA whereas M. leprae specific 16S rRNA gene was amplified in sixteen of these samples. PCR amplification and fragment length analysis showed 91 bp, i.e., three copies of the rpoT 6 bp tandem repeats from soil samples and similar three copies observed in patient samples.

CONCLUSION

Presence of viable M. leprae in the soil having same rpoT genotype of M. leprae noted in patients suggests that it could be the same strain of M. leprae. M. leprae found in the soil could be the one that is excreted out by the patient. Significance of its viability in the environment and its pathogenicity with respect to transmission needs to be further explored. Findings of this study might provide possible insights for further exploration into understanding transmission patterns in leprosy and also will throw light on identifying potential for existence of extra human source or reservoirs of M. leprae, if any.

Mutation at codon 442 in the rpoB gene of Mycobacterium leprae does not confer resistance to rifampicin

BACKGROUND

Rifampicin is the major drug in the treatment of leprosy. The rifampicin resistance of Mycobacterium leprae results from a mutation in the rpoB gene, encoding the β subunit of RNA polymerase. As M. leprae is a non-cultivable organism observation of its growth using mouse food-pad (MFP) is the only Gold Standard assay used for confirmation of "in-vivo" drug resistance.

OBJECTIVE

Any mutation at molecular level has to be verified by MFP assay for final confirmation of drug resistance in leprosy.

MATERIAL AND METHODS

In the present study, M. leprae strains showing a mutation only at codon 442 Gln-His and along with mutation either at codon 424 Val-Gly or at 438 Gln-Val within the Rifampicin Resistance Determining Region (RRDR) confirmed by DNA sequencing and by high resolution melting (HRM) analysis were subjected for its growth in MFP.

RESULT AND CONCLUSION

The M. leprae strain having the new mutation at codon 442 Gln-His was found to be sensitive to all the three drugs and strains having additional mutations at 424 Val-Gly and 438 Gln-Val were conferring resistance with Multi drug therapy (MDT) in MFP. These results indicate that MFP is the gold standard method for confirming the mutations detected by molecular techniques.

Comparative evaluation of PCR amplification of RLEP, 16S rRNA, rpoT and Sod A gene targets for detection of M. leprae DNA from clinical and environmental samples

PURPOSE

PCR assay is a highly sensitive, specific and reliable diagnostic tool for the identification of pathogens in many infectious diseases. Genome sequencing Mycobacterium leprae revealed several gene targets that could be used for the detection of DNA from clinical and environmental samples. The PCR sensitivity of particular gene targets for specific clinical and environmental isolates has not yet been established. The present study was conducted to compare the sensitivity of RLEP, rpoT, Sod A and 16S rRNA gene targets in the detection of M. leprae in slit skin smear (SSS), blood, soil samples of leprosy patients and their surroundings.

METHOD

Leprosy patients were classified into Paucibacillary (PB) and Multibacillary (MB) types. Ziehl-Neelsen (ZN) staining method for all the SSS samples and Bacteriological Index (BI) was calculated for all patients. Standard laboratory protocol was used for DNA extraction from SSS, blood and soil samples. PCR technique was performed for the detection of M. leprae DNA from all the above-mentioned samples.

RESULTS

RLEP gene target was able to detect the presence of M. leprae in 83% of SSS, 100% of blood samples and in 36% of soil samples and was noted to be the best out of all other gene targets (rpoT, Sod A and 16S rRNA). It was noted that the RLEP gene target was able to detect the highest number (53%) of BI-negative leprosy patients amongst all the gene targets used in this study.

CONCLUSION

Amongst all the gene targets used in this study, PCR positivity using RLEP gene target was the highest in all the clinical and environmental samples. Further, the RLEP gene target was able to detect 53% of blood samples as positive in BI-negative leprosy cases indicating its future standardization and use for diagnostic purposes.

Cortisol and proinflammatory cytokine profiles in type 1 (reversal) reactions of leprosy

PURPOSE

Cortisol levels in the circulation and at the sites of peripheral inflammation regulate type 1 (Reversal) reactions in leprosy akin to delayed type hypersensitivity reactions (DTH). In this study we determine the extent to which the differential mRNA expression of genes encoding cortisone-cortisol shuttle enzymes (11 β hydroxysteriod dehydrogenase I & II (11 β HSD I & II)), circulatory levels of proinflammatory cytokines (IL-6, IL-7, IP-10, IL-17F, IL-23, TNF-α, IL-1β, PDGF BB and CRP) and cortisol are associated with development of type 1 reactions in leprosy.

METHODS

Urine, blood and incisional skin biopsy samples from site of lesions were collected from 49 newly diagnosed untreated leprosy cases in T1R and 51 cases not in reaction (NR). mRNA expression levels of genes encoding 11 β HSD I & II in skin biopsy samples were determined by realtime PCR. Cortisol levels from the lesional skin biopsies, serum and urine samples and serum proinflammatory cytokine levels were measured using ELISA.

RESULTS

The mean expression ratios of 11 β HSD I & II are significantly lower in leprosy cases with T1R when compared to the NR leprosy cases. Cortisol levels in lesional skin biopsies and in urine are significantly lower (p=0.001) in leprosy cases with T1R. Serum cytokine levels of IP-10, IL-17F, IL-IL-6 and TNF-α are significantly higher (p<0.05) in leprosy cases with T1R when compared the NR leprosy cases.

CONCLUSION

Our study indicated an association of urinary and lesional skin cortisol levels with the manifestation of T1R in leprosy. IP-10, IL-17F, IL-6 and TNF-α can be potential prognostic serological markers and gene expression markers for early detection of type 1 reactions in leprosy.

Single nucleotide polymorphism-based molecular typing of M. leprae from multicase families of leprosy patients and their surroundings to understand the transmission of leprosy

The exact mode of transmission of leprosy is not clearly understood; however, many studies have demonstrated active transmission of leprosy around a source case. Families of five active leprosy cases and their household contacts were chosen from a high endemic area in Purulia. Fifty-two soil samples were also collected from different areas of their houses. DNA was extracted from slit-skin smears (SSS) and soil samples and the Mycobacterium leprae-specific RLEP (129 bp) region was amplified using PCR. Molecular typing of M. leprae was performed for all RLEP PCR-positive samples by single nucleotide polymorphism (SNP) typing and confirmation by DNA sequencing. SSS of these five patients and six out of the total 28 contacts were PCR positive for RLEP whereas 17 soil samples out of 52 showed the presence of M. leprae DNA. SNP typing of M. leprae from all RLEP PCR-positive subjects (patients and smear-positive contacts) and 10 soil samples showed the SNP type 1 genotype. M. leprae DNA from the five leprosy patients and the six contacts was further subtyped and the D subtype was noted in all patients and contacts, except for one contact where the C subtype was identified. Typing followed by subtyping of M. leprae clearly revealed that either the contacts were infected by the patients or both patients and contacts had the same source of infection. It also revealed that the type of M. leprae in the soil in the inhabited areas where patients resided was also of the same type as that found in patients.

Cohort study of the seasonal effect on nasal carriage and the presence of Mycobacterium leprae in an endemic area in the general population

Leprosy continues to be a significant health problem in certain pockets in developing countries. Better understanding of the transmission and source of the infection would help to decipher the transmission link, leading to control of the spread of the disease. The nose is considered to be a portal of entry, suggesting an aerial route for transmission through droplet infection. The evidence suggests that many individuals from endemic countries carry Mycobacterium leprae in their nasal cavities without having obvious symptoms of leprosy. The objective of the present study was to assess the presence of M. leprae on the nasal mucosa in the general population from a leprosy-endemic pocket. M. leprae detection was carried out using PCR targeting RLEP. Four hundred subjects from an area highly endemic for leprosy were included in the study and followed up during three different seasons--winter, summer, and monsoon--for evidence of nasal exposure to M. leprae. PCR positivity for M. leprae was observed in 29%, 21% and 31% of the samples collected in winter, summer and the monsoon season, respectively. Twenty-six individuals from the cohort showed amplification for M. leprae for all seasons. Our results are consistent with reports in the literature showing widespread exposure to M. leprae in the endemic community. The results also suggest possible association of the environmental conditions (climate) with the transmission pattern and levels of exposure to M. leprae. However, the present study indicated that the population from highly endemic pockets will have exposure to M. leprae irrespective of season.

Single nucleotide polymorphisms typing of Mycobacterium leprae reveals focal transmission of leprosy in high endemic regions of India

Earlier studies indicate that genotyping of Mycobaterium leprae based on single-nucleotide polymorphisms (SNPs) is useful for analysis of the global spread of leprosy. In the present study, we investigated the diversity of M. leprae at eight SNP loci using 180 clinical isolates obtained from patients with leprosy residing mainly in Delhi and Purulia (West Bengal) regions. It was observed that the frequency of SNP type 1 and subtype D was most predominant in the Indian population. Further, the SNP type 2 subtype E was noted only from East Delhi region and SNP type 2 subtype G was noted only from the nearby areas of Hoogly district of West Bengal. These results indicate the occurrence of focal transmission of M. leprae infection and demonstrate that analysis by SNP typing has great potential to help researchers in understanding the transmission of M. leprae infection in the community.

Increased serum circulatory levels of interleukin 17F in type 1 reactions of leprosy

PURPOSE

Leprosy is a chronic infectious disease caused by Mycobacterium leprae affecting mainly skin and peripheral nerves. Acute inflammatory episodes in the borderline immunological spectrum of the disease cause severe nerve and tissue damage leading to deformities. Finding of any serological marker for leprosy reactions will help in prediction of reactions and in early treatment intervention. The objective of this study was to measure the serum circulatory levels of Interleukin 17F (IL 17F) and to correlate the levels with type 1 and type 2 reactional states and with clinico-histopathological spectrum of leprosy. We studied IL 17F to delineate its role and its clinical implications in leprosy reactions.

METHODS

Patients were classified based on the Ridley DS and Jopling WH Classification and blood samples (5 ml each) were collected from 80 active untreated leprosy cases in Type 1 reaction (T1R), 21 cases in Type 2 (Erythema Nodosum Leprosum ENL) reaction (T2R), 80 cases without reaction (NR), and 94 non-leprosy cases (NL). Serum was separated and measured for IL 17F levels using ELISA (Commercial Kits, R&D Systems Inc., USA).

RESULTS

IL 17F levels were significantly higher in the T1R group when compared to the NR group (p < 0.001). The borderline lepromatous group showed the highest levels of IL 17F among the other groups in the disease spectrum. Bacteriological index (BI) showed negative correlation with the IL 17F levels.

CONCLUSION

The results specify that serum circulatory levels of IL 17F are elevated during T1Rs in the borderline spectrum of the disease and thus may play a role in the regulation of inflammatory responses associated with reactions in leprosy.

Dynamics of Mycobacterium leprae transmission in environmental context: deciphering the role of environment as a potential reservoir

Leprosy is a disease caused by Mycobacterium leprae. Various modes of transmission have been suggested for this disease. Transmission and risk of the infection is perhaps related to presence of the infectious cases and is controlled by environmental factors. Evidence suggests that humidity may favor survival of M. leprae in the environment. Several reports show that non-human sources like 'naturally' infected armadillos or monkeys could act as reservoir for M. leprae. Inanimate objects or fomites like articles used by infectious patients may theoretically spread infection. However, it is only through detailed knowledge of the biodiversity and ecology that the importance of this mode of transmission can be fully assessed. Our study focuses here to decipher the role of environment in the transmission of the disease. Two hundred and seven soil samples were collected from a village in endemic area where active cases also resided at the time of sample collection. Slit skin smears were collected from 13 multibacillary (MB) leprosy patients and 12 household contacts of the patients suspected to be hidden cases. DNA and RNA of M. leprae were extracted and amplified using M. leprae specific primers. Seventy-one soil samples showed presence of M. leprae DNA whereas 16S rRNA could be detected in twenty-eight of these samples. Samples, both from the environment and the patients, exhibited the same genotype when tested by single nucleotide polymorphism (SNP) typing. Genotype of M. leprae found in the soil and the patients residing in the same area could help in understanding the transmission link in leprosy.