Mycobacterial infections such as leprosy and tuberculosis can induce autoimmune responses by disrupting host immune homeostasis. We previously identified eight mimicking B cell epitopes (BCEs) with elevated autoantibody levels in Type 1 Reaction (T1R). In this study, we longitudinally evaluated BCE-specific antibody responses and standardized a dot blot assay for T1R detection. A total of 150 untreated leprosy patients were enrolled: 50 each with T1R, Type 2 Reaction (T2R), and non-reactional (NR) cases; however, follow-up of T2R patients was not feasible. Patients were monitored every 3-4 months for changes in antibody profiles. ELISA quantified antibodies against 15 BCEs derived from Mycobacterium leprae (M. leprae) (HSP65, 50 S ribosomal protein, lysyl tRNA synthetase) and host proteins (keratin, myelin basic protein). Dot blot analysis was performed with pooled sera from each group, and cut-off values were derived from NR intensities. Elevated antibodies against HSP2, HSP4-HSP6, KER1, KER2, KER4, MBP50SB1, and MBPLMB2 were strongly associated with T1R and correlated with disease progression in longitudinal analyses. Blot analyses confirmed higher intensities in T1R and T2R compared to NR and healthy controls (HC). Furthermore, future studies with larger longitudinal cohorts and longer follow-up periods are needed to validate these findings and to better characterize changes in autoantibody levels throughout disease progression and treatment, while the identification of these BCEs as potential prognostic biomarkers may also support the adaptation of the dot blot assay into cost-effective lateral flow platforms for clinical screening.

ABSTRACT:Leprosy is a persistent granulomatous disease that occurs due to Mycobacterium leprae infection. Leprosy primarily affects peripheral nerves, skin, and mucous membranes. Reactions in leprosy are immunological complications that may occur at any stage of disease progression, irrespective of treatment status. This review explores the potential link between M. leprae infection and autoimmune responses, emphasizing the role of immune dysregulation in leprosy reactions. We have delineated a comprehensive exploration of reactions in leprosy within the framework of autoimmunity, drawing insights from previously documented research. Biotic elements, including bacteria, might be associated with an imbalance in the host's homeostatic mechanism, leading to an autoimmune response. Mycobacteria have been reported for their potential to modulate host immune responses in both humans and experimental animal models. Pathogens can induce autoimmunity via molecular mimicry during the initiation of the disorder, and they may promote chronic pathologies with inflammation and/or superantigens, prompted by the loss of immunological tolerance to self-antigens, which can lead to systemic or organ-specific damage. Autoimmune manifestations in leprosy are triggered by the impairment of the regulatory mechanisms of the host due to M. leprae infection. Leprosy reactions are influenced by autoimmune processes triggered by M. leprae infection. Understanding the immunological interactions between the pathogen and the host may provide insights into disease management and therapeutic strategies.

Background:India alone contributes nearly 54% of the global load of new cases of leprosy and 21% to global helminthic parasitic infection cases. Research studies have suggested that Soil-transmitted helminth (STH) infection can regulate the host's immune response and make them susceptible to leprosy. This study aimed to investigate the association between helminth infection and leprosy. Materials & Methods:Stool samples (n=360) were collected from 96 patients and 264 household contacts (HHCs) from the endemic region in Purulia (West Bengal) and Champa (Chhattisgarh) India. Samples were examined microscopically for the presence of intestinal helminthic parasites; Cytokine profiling (IFN-γ, IL-12, IL-10) was performed by ELISA on a subset of helminth-positive and negative patients to assess immune responses. Results:Intestinal parasites were detected in 26% of leprosy patients and 17% of HHCs. Male patients with helminth infection had a significantly higher risk of multibacillary leprosy (OR = 2.60; 95% CI: 1.22-5.55; p = 0.019); no significant association was observed in females or overall, between cases and HHCs. IFN-γ levels were significantly reduced in helminth-positive cases (mean 19.70 pg/ml) compared to helminth-negative cases (mean 46.60 pg/ml; p < 0.02), indicating Th1 suppression. IL-12 and IL-10 levels did not differ significantly between groups. Over five years, 30 HHCs developed leprosy, but no significant association with baseline helminth status was observed (p = 0.816). Conclusion:Although STH co-infection suppressed Th1 responses in leprosy patients, no direct population-level association with leprosy incidence was established. Integrated parasite control measures may complement leprosy programs by mitigating potential immunomodulatory risks, particularly in high-burden settings.

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.

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.

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.

OBJECTIVES:Purulia is one of the high-endemic districts for leprosy in West Bengal (the 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 provided evidence of secondary drug resistance in relapse cases of leprosy. The aim of the current study was to observe primary drug resistance patterns for dapsone, rifampicin, and ofloxacin amongst new leprosy patients from Purulia, West Bengal in order to better understand the emergence of primary resistance to these drugs. METHODS:In the present study, slit-skin smear samples were collected from 145 newly diagnosed leprosy cases from The Leprosy Mission (TLM) Purulia hospital between 2017 and 2018. DNA was extracted from these samples and the Mycobacterium leprae genome was analyzed for genes associated with drug resistance by polymerase chain reaction (PCR), followed by Sanger sequencing. Wild-type strain (Thai-53) and mouse footpad-derived drug-resistant strain (Z-4) were used as reference strains. RESULTS:Of 145 cases, 25 cases showed mutations in genes associated with resistance to rifampicin, dapsone, and ofloxacin (as described by the World Health Organization, rpoB, folP, and gyrA, respectively) through Sanger sequencing. Of these 25 cases, 16 cases showed mutations in ofloxacin, two cases showed mutations in combinations of ofloxacin and rifampicin, four cases showed a mutation only in rifampicin, one case showed mutations in combinations of rifampicin and dapsone, and two cases showed mutations only in dapsone. CONCLUSION:Results from this study indicated the emergence of resistance to antileprosy 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 this endemic region (i.e., Purulia, West Bengal), posing challenges for the effective treatment of rifampicin-resistant cases.

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.

IntroductionImmunological reactions are frequent complications that may occur either before, during, or after treatment and affect 30–50% of leprosy patients. The presence of autoantibodies like rheumatoid factor, antinuclear factor, and antibodies to host collagen, keratin, actin, myosin, endothelial cells, and myelin basic protein (MBP) has been earlier reported in leprosy patients. The purpose of this study was to identify cross-reactive proteins in clinical samples such as saliva and slit skin scrapings (SSS) of leprosy patients which could be utilised as prognostic biomarkers for Type 1 Reaction (T1R) in leprosy.MethodA total of 10 leprosy patients in T1R and 5 healthy volunteers were recruited. The protein was extracted from their SSS and saliva samples, thereafter, isoelectric focusing (IEF) and two-dimensional PAGE were performed to analyse the proteins. Furthermore, the cross-reactivity was identified by western blotting host proteins in gel against purified IgG from Mycobacterium leprae soluble antigen (MLSA)- hyperimmunized rabbit sera, thereafter, cross-reactive proteins were identified by MS/MS. The cross-reactive host proteins were analysed for homologous bacterial proteins and B cell epitopes (BCEs) were predicted by using bioinformatic tools.ResultsA total of five spots of salivary proteins namely S100-A9, 35.3 kDa, and 41.5 kDa proteins, Serpin peptidase inhibitor (clade A), Cystatin SA-III, and four spots of SSS namely 41.4 kDa protein, Alpha-1 antitrypsin, vimentin, and keratin 1, were identified as cross-reactive. Further, a total of 22 BCEs of cross-reactive host proteins were predicted and visualised.DiscussionThis data provides strong evidence of cross-reactivity/molecular mimicry between host and pathogen in leprosy patients with reaction. These BCEs of cross-reactive proteins could be further studied to predict reactions and may be utilised as an early diagnostic biomarker for T1R in leprosy.

The immune system is a dynamic network of cells and cytokines are the major mediators of immune responses which combat pathogens. Based on the cytokine production, effector T cells differentiate into subsets known as Th1, Th2, Th17, or Treg. This system serves as a barrier to intracellular pathogens, bacterial infections and stimulates the production of reactive oxygen species (ROS), reactive nitrogen intermediates, and nitric oxide, which diffuses across membranes and engulfs intracellular pathogens. Oxidative stress occurs when ROS, reactive nitrogen species (RNS) production, and antioxidant defences become imbalanced. Oxidative stress generated by infected cells produces a substantial amount of free radicals which enables the killing of intracellular pathogens. Intracellular pathogens are exposed to endogenous ROS as part of normal aerobic respiration, also exogenous ROS and RNS are generated by the host immune system in response to infection. Nanoparticles which are designed for drug delivery are capable of trapping the desired drug in the particles which protect the drug from enzymatic degradation in a biological system. The subcellular size of nanoparticles enables higher intracellular uptake of the drug which results in the reduction of the concentration of free drugs reducing their toxic effect. Research on the modulation of immune response and oxidative stress using nanoparticles used to encapsulate drugs has yet to be explored fully. In this review, we illustrate the immune activation and generation of oxidative stress properties which are mediated by nanoparticle encapsulated drug delivery systems which can make the therapy more effective in case of diseases caused by intracellular pathogens.

Several Mycobacterial infections including leprosy and tuberculosis are known to evoke autoimmune responses by modulating homeostatic mechanism of the host. Presence of autoantibodies like, rheumatoid factor, anti-nuclear factor and antibodies to host, collagen, keratin, myelin basic protein (MBP) and myosin, have been earlier reported in leprosy patients. In the present study, we detected the role of mimicking epitopes between Mycobacterium leprae and host components in the induction of autoimmune response in leprosy. Based on our previous findings, we predicted and synthesized a total of 15 mimicking linear B cell epitopes (BCE) and 9 mimicking linear T cell epitopes (TCE) of keratin and MBP. Humoral and cell-mediated immune responses against these epitopes were investigated in Non-reaction (NR), Type 1 reaction (T1R) leprosy patients, and healthy controls. We observed significantly higher levels of antibodies against 8 BCE in T1R in comparison to NR leprosy patients. Further, we also found 5 TCE significantly associated with lymphocyte proliferation in the T1R group. Our results indicated that these epitopes play a key role in the induction of autoimmune response in leprosy and are also strongly associated with the inflammatory episodes of T1R. Conclusively, these molecules may be employed as a biomarker to predict the inflammatory episodes of T1R.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae and/or by Mycobacterium lepromatosis.[12] The disease mainly affects the peripheral nerves, skin, and mucous membranes and if left untreated it may lead to nerve damage and deformity. Use of diamino diphenyl sulphone (DDS), also called dapsone, for treatment of leprosy began in 1945[3] and DDS monotherapy continued till the appearance of primary and secondary DDS resistance during the 1970s.[45] Most of these DDS-resistant cases originated from fully treated relapse cases. However, it was noted that low doses of dapsone and irregular treatment were the major causes of relapse.[5] Later when rifampicin, a bactericidal drug, was tried in a mono-therapeutic mode, M. leprae developed resistance also to this drug.[6] Considering the above, the multidrug therapy (MDT) approach was adopted like tuberculosis chemotherapy[7] in leprosy elimination by combining DDS with bactericidal drug, rifampicin, and an anti-bacterial drug, clofazimine with anti-inflammatory activity. After finding this MDT combination effective in curing leprosy, it was implemented in 1982 worldwide by the World Health Organization (WHO) for the elimination of leprosy.[8] Because of this robust MDT regimen, the prevalence of leprosy was brought down to <1 case/10,000 population (an elimination figure assigned by WHO) by the year 2002 worldwide.[9] Similarly, in India, the prevalence of leprosy which was 25.9/10,000 in 1991 was brought down to <1/10,000 in 2005 after the introduction of MDT under the elimination program.[10] During this critical juncture of elimination, WHO has drawn up a strategical road map from the year 2021 to 2030 focussing toward Zero leprosy target.[11] However, at the moment although the prevalence of leprosy has gone down to 0.22/10,000 worldwide[12] and to 0.66/10,000 in India,[13] a total number of 202,185 new cases including 14,981 child cases are appearing in the world.[14] India is still housing 114,451 (57%) of these new cases of the world. These data clearly indicate that despite the continuation of effective chemotherapeutic preventive measures by MDT for more than 4 decades, the transmission of the disease is continuing in the community. Leprosy being a chronic disease with a known long period of incubation (>20 years),[12] a total elimination program with Zero leprosy target by 2030 may be too optimistic.[15] For any elimination/eradication program of an infectious chronic disease such as leprosy, effective chemotherapy with 100% full cure of the disease is one of the most important aspects of a control measure. The disease being dynamic in nature with a range of clinical manifestations exhibited by the host in response to infection has been well classified by Ridley and Jopling[16] based on a bacteriological and immuno-histological scale. However, for making the treatment procedure very handy at the field level, the disease manifestation has been simplified and classified by WHO as paucibacillary (PB = presence of 1–5 skin lesions) and multibacillary (MB = presence of >5 skin lesions) and recommended treatment of the disease with 12 months of MDT for MB and 6 months of MDT for PB cases.[12] Further, as the bacterial index (BI) and the activity of the lesions are not seriously considered at the field level, the patients are considered as cured cases and are released from treatment after the completion of fixed-dose MDT. MB cases harboring a wide range in M. leprae population varying between 1+ and 5+ BI receive 12 monthly doses of 600 mg each of the bactericidal drug, rifampicin which has a half-life of only two and half hours.[17] It has been shown that despite full treatment with MDT for 2 or 3 years, M. leprae is able to persist as viable bacilli as shown by the growth in mouse footpad (MFP) or by measuring adenosine triphosphate levels using bioluminescence assay.[181920] Later, the presence of viable M. leprae has also been reported from fully treated PB cases also with a history of relapse.[21] In addition, it is also not very uncommon to find defaulters during the course of MDT. The percentage of nonadherence to fixed-dose MDT (defaulters) varied between ≈50% and ≈60% and has been noted predominantly in patients with MB.[222324] Hence, it was expected that relapses would occur from the pool of defaulters or from fully treated leprosy cases due to the growth of the remaining viable M. leprae bacilli which have not been killed by MDT. A recent cohort study conducted by our group in the Leprosy Mission Hospitals in India on MB patients with high BI (≥3+) showed the presence of viable M. leprae employing quantitative reverse transcription-polymerase chain reaction for the gene expression level of hsp18 gene (encoding the heat shock 18 kDa protein) and esxA gene (encoding ESAT-6 protein) which were found to correlate with the exponential growth of M. leprae in MFP[25] in skin biopsies from fully treated cases (Under publication). The remaining viable bacilli in such fully treated highly bacillated MB cases will be able to grow because in such patients' cell-mediated immunity to M. leprae remain suppressed for a long time.[26] If these relapse cases are not diagnosed and treated immediately, they will act as a source of infection and will be responsible for the transmission of the disease in the community. Earlier relapses during DDS monotherapy[27282930] associated with the emergence of both primary and secondary drug resistance to DDS[45] sufficiently delayed the progress of the leprosy control program till MDT with the bactericidal drug rifampicin was launched in 1982.[8] Now, after more than 4 decades of MDT, relapses are often being noted due to drug resistance against rifampicin. Resistance to rifampicin and other bactericidal drugs such as ofloxacin has been reported from most of the leprosy endemic countries such as Brazil, China, Colombia, Malaysia, Korea, Myanmar, Indonesia, Philippines, Japan, and India.[3132333435363738] A recent study in Colombia showed a significantly higher percentage of resistance to rifampicin in newly diagnosed cases as compared with treated cases.[39] Considering the gravity of the situation, WHO initiated a multicentric study which continued for 10 years to look for the distribution of drug resistance in the endemic countries of the world. It was noted that of 1143 relapses 58 (5.1%) and of 789 new MB cases, 16 (2%) were resistant to rifampicin.[40] These studies clearly indicated that the rifampicin-resistant strain is transmitting the disease in the community. These results immediately directed WHO to take an account of the background data on antimicrobial resistance (AMR) through a global consultation of the experts of leprosy endemic countries without any data for drug resistance between 2014 and 2020 from India which holds >50% of the world population of leprosy cases.[41] Further, WHO has recently organized a virtual meeting of the global experts and presented AMR surveillance data from all the endemic countries and considered that threat due to AMR is not yet there and hence leprosy elimination program can continue with the first-line drug regimen. However, it was decided that the continuation of AMR surveillance following the WHO guidelines should be continued.[42] Although relapse in leprosy gathered momentum for search for the occurrence of AMR from cases of relapse and was taken as a probable strong indicator for patients being resistant to MDT, around the same time, there were reports of the occurrence of drug resistance from recurrent reactional cases (both type 1 and type 2) by various tertiary care hospitals.[4344454647] Although type 1 reactions may occur in about 20–40% of MB leprosy cases,[484950515253] type 2 reactions [or erythema nodosum leprosum (ENL)] have been reported in about 10% of borderline lepromatous[54] and from more than 50% in lepromatous leprosy cases.[55] All these studies strongly indicate that patient manifesting reactions is a very common phenomenon during therapy and after completion of MDT and therefore, reactional patients should be screened for M. leprae drug-resistant strains under the leprosy elimination program. Further, a recent retrospective cohort study showed that M. leprae drug-resistant strains for all three drugs may also be associated with neuropathy in leprosy.[56] In the background scenario of the emergence of M. leprae-resistant strains during MDT therapy and post-MDT therapy, various research groups are engaged in reducing the transmission of leprosy with a chemotherapeutic approach by administration of single-dose rifampicin (SDR) as a leprosy post-exposure prophylaxis (LPEP) measure to contacts of newly diagnosed leprosy cases.[57] Therefore, in 2008 a cluster-randomized placebo control double-blind trial in Bangladesh named contact transmission and chemoprophylaxis in leprosy was conducted. It was noted that SDR was effective for the first 2 years in reducing the incidence by 57%. However, after 2 years there was no difference in the protective efficacy for leprosy between the SDR and placebo control groups.[58] During the DDS monotherapy era in the 1960s and 1970s, chemoprophylaxis trials were also conducted in Uganda and India with the administration of contact population with dapsone and acedapsone, respectively, for the control of leprosy. These trials although showed about 85% decline in the prevalence of leprosy but ultimately the protective efficacy waned with time as there was no effect of dapsone chemoprophylaxis on the incidence of leprosy. Further, during that time reports on the rise in dapsone resistance cases in the population also did not favor the implementation of dapsone chemoprophylaxis in the control program.[59606162636465] Although SDR chemoprophylaxis of contacts of newly diagnosed patients did not show any difference in protective efficacy after 2 years between the SDR and placebo group, the SDR chemoprophylaxis was introduced into the program because of its immediate protective effect on the development of leprosy in the newly diagnosed leprosy contact population of the world for ultimate reduction in transmission of infection and consequently in the emergence of new leprosy cases in the world. Initially, a feasibility study conducted for the implementation of SDR to the contacts of newly diagnosed patients under the control program in Brazil, India, Indonesia, Myanmar, Nepal, Sri Lanka, and Tanzania showed that LPEP with SDR is well tolerated and can be easily implemented in the leprosy control program of the endemic countries. Following this, SDR has been implemented under the direction of WHO in the elimination program in 2018 in all endemic countries worldwide.[66] From the above, it is clear that secondary and primary resistance to rifampicin and ofloxacin are on the rise which has been established by screening relapse and newly diagnosed MB cases from the leprosy endemic countries.[31323334353637383940] Further, the annual records also show a gradual rise of relapse cases (from 2844 of 2016 to 3897 of 2019)[146768] under the elimination program. In addition, reports of isolation of rifampicin drug-resistant strains from both type 1 and type ENL cases which are being reported from various research groups are of great concern as this has not been taken up yet in the M. leprae-resistant strain surveillance mechanism under the program. As leprosy cases with reactions are difficult to treat under field conditions, these cases are mostly referred to and treated in tertiary care hospitals having indoor facilities. All these findings strongly indicate that both rifampicin and ofloxacin-resistant M. leprae strains released from the relapse and reaction cases are slowly spreading infection in the endemic population. Introduction of SDR in such a situation might induce more drug pressure and might help M. leprae strain to become more resistant to the prescribed drugs and could further help in the survival of M. leprae-resistant strain in the endemic community for the propagation of infection for a long time to come. Although the problem of AMR is now very focal in distribution, the drug pressure in the community might rather help in further maintenance and propagation of AMR strain in the community. Therefore, the WHO strategic plan "Toward Zero leprosy by 2030"[11] might direct its priority to monitor both relapses and reactions in leprosy which are occurring due to drug-resistant M. leprae to the primary bactericidal drug rifampicin and the second-line drugs, ofloxacin and clarithromycin. Although most of the resistant cases have been reported in patients who have relapsed after MDT indicated the appearance of secondary drug resistance to either rifampicin or ofloxacin or both;[3536] however, the emergence of primary drug resistance to rifampicin and ofloxacin in an endemic population is an early indication for drug-resistant M. leprae strain transmission in the community.[37] It has been often mentioned that the relapse rate in the community is very low and hence it will not have much impact on the leprosy elimination program.[40] However, it may be emphasized that report of relapse and reaction in the community is generally late and mostly the cases land up in tertiary care hospitals because of their need for personalized treatment. Considering the above points mentioned, the journey toward Zero leprosy by 2030 may not be attainable without directing its priority to the establishment of a robust surveillance mechanism for relapse and reactions in leprosy. Therefore, it is recommended that the following strategy should be adopted immediately to check the transmission of AMR strains of M. leprae in the endemic community are as follows: Establishment of a robust setup for early diagnosis of relapse and reactions in leprosy at the field level and their molecular screening for mutations for drug resistance to DDS, rifampicin, ofloxacin, and clarithromycin. Screening of all new MB cases for the presence of molecular mutations for primary drug-resistant strains to DDS, rifampicin, ofloxacin, and clarithromycin. Once a drug resistance case to the above drugs is identified, the close contacts in the family should be screened for early detection of transmission of drug-resistant M. leprae strains in the family. After identification of either primary or secondary drug-resistant cases, the patient should be treated adequately with an alternative regimen for the cure of leprosy. Acknowledgement The authors acknowledge the staff of SBL and TLMTI for their help.

ObjectiveTo elucidate the spectrum of findings on neuroimaging in leprosy with special reference to magnetic resonance imaging (MRI).MethodsWe retrospectively reviewed the neuroimaging findings on MRI in thirty-two patients with leprosy where dedicated plexus, brain and spine imaging had been performed.ResultsTwenty-two patients had positive findings on imaging. Six patients showed involvement of the peripheral nerves as thickening and formation of micro or macroabscesses. The brachial plexus showed thickening and hyperintensity in ten patients, with associated involvement of the lumbosacral plexus in one patient. Four patients showed spinal cord involvement as discrete T2 hyperintense lesions with postcontrast enhancement. Intracranial lesions involving the nucleus ambiguus and facial colliculus were seen in two patients.ConclusionNeuroimaging in Hansen's disease has brought several new findings to the fore front. Besides peripheral nerves, involvement of the centrally located plexuses, spinal cord and brain has also been seen which thus expands the imaging spectrum of the disease.

The immune system is a dynamic network of cells and cytokines are the major mediators of immune responses which combat pathogens. Based on the cytokine production, effector T cells differentiate into subsets known as Th1, Th2, Th17 or Treg (T regulatory). This system serves as a barrier to intracellular pathogens, bacterial infections and stimulates the production of reactive oxygen species (ROS), reactive nitrogen intermediates (RNI) and nitric oxide (NO), which diffuses across membranes and engulfs intracellular pathogens. Oxidative stress occurs when ROS, reactive nitrogen species (RNS) production and antioxidant defences become imbalanced. Oxidative stress generated by infected cells produces a substantial amount of free radicals which enables killing of intracellular pathogens. Intracellular pathogens are exposed to endogenous ROS as part of normal aerobic respiration, also aexogenous ROS and RNS are generated by the host immune system in response to infection. Nanoparticles which are designed for drug delivery are capable of trapping the desired drug in the particles which protects the drug from enzymatic degradation in a biological system. The small (subcellular) size of nanoparticles enables higher intracellular uptake of the drug which results in the reduction of the concentration of free drugs reducing their toxic effect. Research on the modulation of immune response and oxidative stress using nanoparticles used to encapsulate drugs has yet to be explored fully. In this review we illustrate the immune activation and generation of oxidative stress properties which are mediated by nanoparticle encapsulated drug delivery systems which can make the therapy more effective in case of diseases caused by intracellular pathogens.

Resistance to anti-leprosy drugs is on the rise. Several studies have documented resistance to rifampicin, dapsone, and ofloxacin in patients with leprosy. We looked for point mutations within the folP1, rpoB, and gyrA gene regions of the Mycobacterium leprae genome predominantly in the neural form of leprosy. DNA samples from 77 nerve tissue samples were polymerase chain reaction (PCR)-amplified for M leprae DNA and sequenced for drug resistance-determining regions of genes rpoB, folP1, and gyrA. The mean age at presentation and onset was 38.2 +/- 13.4 (range 14-71) years and 34.9 +/- 12.6 years (range 10-63) years, respectively. The majority had borderline tuberculoid leprosy (53 [68.8%]). Mutations associated with resistance were identified in 6/77 (7.8%) specimens. Mutations seen were those associated with resistance to rifampicin, ofloxacin, and dapsone. All the six patients were drug-naive. The clinical and pathological manifestations in this group did not differ from the drug-sensitive group. This study highlights the occurrence of resistance to the standard multidrug therapy and ofloxacin in leprosy. Among the entire cohort, 1/77 (1.3%) showed resistance to rifampicin, 2/77 (2.6%) to dapsone, and 5/77 (6.4%) to ofloxacin. Six new patients showing infection by mutant strains indicated the emergence of primary resistance. Resistance to ofloxacin could be due to frequent use of quinolones for many bacterial infections. The results of the study indicate the need for development of a robust and strict surveillance system for detecting drug resistance in leprosy in India.

Identification of Mycobacterium leprae DNA by polymerase chain reaction (PCR) is a reliable and an affordable method to confirm leprosy. DNA from 87 nerve samples (61 from paraffin blocks and 26 fresh samples) was extracted. Mycobacterium leprae DNA was amplified by PCR from 80/87 (92%) specimens. Patients were seen over a period of 11 years (2007-2019), and leprosy was diagnosed based on clinical and characteristic histopathology findings. The clinical diagnostic possibilities were as follows: leprous neuropathy in 73/80 (91.3%), mononeuritis multiplex of unknown etiology in four (5.0%), vasculitic neuropathy in two (2.5%), and distal symmetric sensory motor neuropathy in one (1.3%). The biopsied nerves were as follows: superficial radial = 34 (42.6%), dorsal cutaneous branch of ulnar = 19 (23.8%), sural = 18 (22.5%), and superficial peroneal = 9 (11.3%), and corresponding neurological deficits were recorded in 77 (96.3%) cases. The histopathological diagnoses in total group were as follows: (borderline tuberculoid (BT) = 52, tuberculoid (TT) = 8, borderline lepromatous (BL) = 8, borderline borderline (BB) = 3, nonspecific inflammation = 3, healed/fibrosed = 4, and axonopathy = 2). Acid fast bacilli (AFB) was demonstrated in 11 (13.7%) samples. For comparison, 31 clinically and histopathologically defined non-leprous disease control nerves (inherited neuropathy = 20, vasculitis = 8, and nutritional neuropathy = 3) subjected to PCR were negative for M. leprae DNA. In most instances, there are multiple thickened peripheral nerves in suspected cases of leprosy, but neurological deficits pertaining to the thickened nerve are not as widespread. The current findings emphasize the importance of selecting the most appropriate nerve for biopsy to obtain a positive PCR result. We infer that clinical, histopathological, and PCR tests complement each other to help achieve a definitive diagnosis of leprosy particularly in pure neuritic leprosy and in leprous neuropathy with negative skin smears/biopsy.