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, IL1ß, 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.

Uncommon Presentation of Leprosy: A Report of Two Cases.

Lazarine leprosy is an unusual expression of usually borderline tuberculoid (BT) form characterized by spontaneous ulceration of skin lesions. This is presumably the result of an exaggerated type 1 reaction. It commonly occurs in the BT, borderline lepromatous forms and rarely in the lepromatous forms of leprosy. We report two cases of lazarine leprosy in the BT and BT downgrading to borderline lepromatous spectrum in healthy and immunocompetent males.

Eosinophil Granule Proteins Involvement in Acute Appendicitis-An Allergic Disease?

Several pieces of evidence point to an allergic component as a trigger of acute appendicitis. As the Th2 immune response is characterized by eosinophil mobilization to the target organ and release of their cationic granule proteins, it is reasonable to investigate if the degranulation of eosinophils could be associated with the local injury. The primary aim of this study is to evaluate the participation of eosinophils granules proteins in acute appendicitis, both at local and systemic levels and the secondary aim is to evaluate the diagnostic accuracy of eosinophils granules proteins for the detection of acute appendicitis, as well as for distinguishing between complicated and uncomplicated acute appendicitis. Eosinophil-derived neurotoxin (EDN), eosinophil cationic protein (ECP) and eosinophil peroxidase (EP) are the most well-known eosinophil granule proteins. From August 2021 to April 2022, we present a prospective single-center study to evaluate the EDN, ECP, and EP concentrations simultaneously in appendicular lavage fluid (ALF) and the serum of 22 patients with acute phlegmonous appendicitis (APA), 24 with acute gangrenous appendicitis (AGA), and 14 normal controls. Concerning EDN, no differences were found between groups. ECP concentrations in ALF and serum were significantly higher in the histologically confirmed acute appendicitis compared to the control groups (p < 0.0001 and p < 0.0001, respectively). In ALF, no differences were found between ECP levels in APA: 38.85 ng/mL (IQR 26.50-51.77) and AGA 51.55 ng/mL (IQR 39.55-70.09) groups (p = 0.176). In the serum, no difference was found between ECP levels at APA: 39 ng/mL (IQR 21.30-56.90) and AGA: 51.30 ng/mL (IQR 20.25-62.59) (p = 0.100). For EP, the concentrations in ALF (p < 0.001) and serum (p < 0.001) were both higher in acute appendicitis compared to the control. In ALF, no difference was found between APA: 240.28 ng/mL (IQR 191.2-341.3) and AGA: 302.5 (IQR 227.7-535.85) (p = 0.236). In the serum, no differences were found between APA: 158.4 ng/mL (IQR 111.09-222.1) and AGA: 235.27 (IQR 192.33-262.51) (p = 0.179). Globally, the ALF concentrations were higher than serum concentrations, reflecting an intense inflammatory local reaction in AA. The optimal ECP cut-off for discriminating between acute appendicitis and the controls was >11.41 ng/mL, with a sensitivity of 93.5%, but with a specificity for identifying appendicitis of 21.4%, good discriminative power (AUC = 0.880). For EP, the optimal cut-off was >93.20 ng/mL, with a sensitivity of 87%, but with a specificity of 14.3% (AUC = 0.901), excellent discriminative power. For the diagnosis of perforated AA, the discriminative power of ECP and EP serum concentrations are weak (AUC = 0.562 and AUC = 0.664, respectively). Concerning the presence of peritonitis, the discriminative power of ECP and EP serum concentrations is acceptable, respectively: AUC = 0.724 and AUC = 0.735. Serum levels of EDN (p = 0.119), ECP (p = 0.586) and EP (p = 0.08) in complicated appendicitis were similar to uncomplicated appendicitis. Serum concentrations of ECP and EP can be added to decision-making AA diagnosis. A Th2-type immune response is present in AA. These data bring forward the role of an allergic reaction in the pathogenesis of acute appendicitis.

Solitary plaque of borderline lepromatous leprosy clinically masquerading as paucibacillary leprosy.

Borderline lepromatous (BL) leprosy typically manifests as numerous asymmetric ill-defined macules or infiltrated plaques. Localized cutaneous involvement in BL leprosy is infrequently reported. Type 2 reaction (T2R), an immune complex syndrome, occurs in patients with BL and lepromatous leprosy, as crops of tender evanescent papules or nodules with constitutional symptoms. T2R can also present with various atypical morphologies and rarely as type 1 reaction (T1R), thereby creating a diagnostic dilemma.

Metformin as adjunctive therapy in combination with multidrug treatment for multibacillary leprosy: A protocol for a randomized double-blind, controlled Phase 2 trial in Indonesia (MetLep Trial).

Background: The clinical management of leprosy is complicated by leprosy reactions (LR) causing irreversible nerve damage and disabilities. LR often require long-term use of corticosteroids causing serious side effects. Adjunct host-directed therapy (HDT) is a potentially attractive strategy in leprosy to prevent LR and associated immunopathology, modulate immunological memory that protects against recurrence, and thereby reduce nerve damage, disability and corticosteroid-associated morbidities. Metformin, a well-tolerated, safe and cheap anti-hyperglycaemic drug, is repurposed as HDT in auto-immune and infectious diseases, like tuberculosis (TB). Metformin use in people with diabetes is associated with reduced risks of TB-infection, progression to active TB, treatment failure and TB-mortality. Given the similarities both mycobacteria share, we hypothesize that among persons with multibacillary (MB) leprosy, adjunctive metformin may prevent/mitigate LR. Methods: We will perform a double-blind controlled proof-of-concept trial in which people with newly diagnosed multibacillary leprosy will be randomized (1:1) to metformin hydrochloride 1000mg extended release once daily versus placebo for 24 weeks in addition to standard-of-care WHO MB multidrug therapy (MDT) during 48 weeks. We aim to enrol 166 participants aged between 18 and 65 years, across five clinical sites in two leprosy endemic areas in Indonesia. Primary outcomes are the proportion of participants experiencing a LR and the frequency of (serious) adverse events. Secondary outcomes are the severity and time to first LR, the cumulative corticosteroid usage, and quality of life. The total study follow-up is 48 weeks. Discussion: LR signify the most important cause of irreversible nerve damage leading to anatomical deformities and disabilities, imposing a social and financial burden on those affected. Our study aims to evaluate the efficacy, tolerability and safety of adjunct metformin added to MDT in persons with multibacillary leprosy, and explore its effects on clinical and immunological outcomes. ClinicalTrialsgov registration: NCT05243654 (17/02/2022).

Cutaneous ulceration as a presenting feature of type 1 lepra reaction: A case report.

Reactions in leprosy represent sudden shift in the immunological response and are seen in 11-25% of affected patients. It can be seen before, during or after the completion of multidrug therapy (MDT).1 Two types of reactions are recognized; Type 1 reaction (T1R), seen in borderline leprosy, affecting mainly skin and nerves; type 2 reaction (T2R) or erythema nodosum leprosum (ENL), seen in lepromatous leprosy, characterized by systemic features in addition to cutaneous lesions. Trophic ulcers and ulcerating ENL are well known entities while cutaneous ulceration in T1R is extremely rare; we describe an immune-competent woman with cutaneous ulceration as a presenting feature to highlight the need to recognize this entity at the earliest opportunity.

Rare occurrence of lepra type 1 reaction in pure neuritic leprosy: A case report.

Type 1 reaction in pure neuritic leprosy usually occurs in the form of neuritis. The development of new skin lesion during reaction is rare. Clinicians should be aware about occurrence of type 1 reaction in pure neuritic leprosy.

Ofloxacin-Containing Multidrug Therapy in Ambulatory Leprosy Patients: A Case Series.

BACKGROUND: Standard dapsone and clofazimine-containing multidrug therapy (MDT) for leprosy is limited by drug tolerability, which poses treatment adherence barriers. Although ofloxacin-based regimens are promising alternatives, current efficacy and safety data are limited, particularly outside of endemic areas. We evaluated treatment outcomes in patients with leprosy receiving ofloxacin-containing MDT (OMDT) at our center. METHODS: We performed a retrospective chart review of patients treated for leprosy at our center over an 8-year period (2011-2019). Primary outcomes evaluated were clinical cure rate, occurrence of leprosy reactions, antibiotic-related adverse events, and treatment adherence. Analyses were descriptive; however, data were stratified by age, sex, spectrum of disease, region of origin, and treatment regimen, and odds ratios were reported to assess associations with adverse outcomes. RESULTS: Over the enrolment period, 26 patients were treated with OMDT (n = 19 multibacillary, n = 7 paucibacillary), and none were treated with clofazimine-based standard MDT. At the time of analysis, 23 patients (88%) had completed their course of treatment, and all were clinically cured, while 3 (12%) were still on treatment. Eighteen patients (69%) experienced either ENL (n = 7, 27%), type 1 reactions (n = 7, 27%), or both (n = 4, 15%). No patients stopped ofloxacin due to adverse drug effects, and there were no cases of allergic hypersensitivity, tendinopathy or rupture, or C. difficile colitis. CONCLUSIONS: We demonstrate a high cure rate and tolerability of OMDT in this small case series over an 8-year period, suggesting its viability as an alternative to standard clofazimine-containing MDT.

Multidrug resistance as a cause of steroid-nonresponsive downgrading type I reaction in Hansen's disease.

While Type 1 reaction in Hansen's disease is commonly encountered, the triggers and reasons for its persistence are not well understood even though the immunological milieu and cytokine interplay have been studied. Herein, we present a case of Type 1 downgrading reaction in which multidrug resistance was the probable cause of steroid-nonresponsiveness and which responded promptly on starting alternate antileprosy treatment.

Pleiotropic effects for Parkin and LRRK2 in leprosy type-1 reactions and Parkinson's disease.

Type-1 reactions (T1R) are pathological inflammatory episodes and main contributors to nerve damage in leprosy. Here, we evaluate the genewise enrichment of rare protein-altering variants in 7 genes where common variants were previously associated with T1R. We selected 474 Vietnamese leprosy patients of which 237 were T1R-affected and 237 were T1R-free matched controls. Genewise enrichment of nonsynonymous variants was tested with both kernel-based (sequence kernel association test [SKAT]) and burden methods. Of the 7 genes tested 2 showed statistical evidence of association with T1R. For the LRRK2 gene an enrichment of nonsynonymous variants was observed in T1R-free controls (PSKAT-O = 1.6 × 10-4). This genewise association was driven almost entirely by the gain-of-function variant R1628P (P = 0.004; odds ratio = 0.29). The second genewise association was found for the Parkin coding gene PRKN (formerly PARK2) where 7 rare variants were enriched in T1R-affected cases (PSKAT-O = 7.4 × 10-5). Mutations in both PRKN and LRRK2 are known causes of Parkinson's disease (PD). Hence, we evaluated to what extent such rare amino acid changes observed in T1R are shared with PD. We observed that amino acids in Parkin targeted by nonsynonymous T1R-risk mutations were also enriched for mutations implicated in PD (P = 1.5 × 10-4). Hence, neuroinflammation in PD and peripheral nerve damage due to inflammation in T1R share overlapping genetic control of pathogenicity.

Reaction centers of the thermophilic microaerophile, Chloracidobacterium thermophilum (Acidobacteria) I: biochemical and biophysical characterization.

Chloracidobacterium thermophilum is a microaerophilic, anoxygenic member of the green chlorophototrophic bacteria. This bacterium is the first characterized oxygen-requiring chlorophototroph with chlorosomes, the FMO protein, and homodimeric type-1 reaction centers (RCs). The RCs of C. thermophilum are also unique because they contain three types of chlorophylls, bacteriochlorophyll aP esterified with phytol, Chl aPD esterified with Δ2,6-phytadienol, and Zn-BChl aP' esterified with phytol, in the approximate molar ratio 32:24:4. The light-induced difference spectrum of these RCs had a bleaching maximum at 839 nm and also revealed an electrochromic bandshift that is probably derived from a BChl a molecule near P840+. The FX [4Fe-4S] cluster had a midpoint potential of ca. - 581 mV, and the spectroscopic properties of the P+ F X - spin-polarized radical pair were very similar to those of reaction centers of heliobacteria and green sulfur bacteria. The data further indicate that electron transfer occurs directly from A0- to FX, as occurs in other homodimeric type-1 RCs. Washing experiments with isolated membranes suggested that the PscB subunit of these reaction centers is more tightly bound than PshB in heliobacteria. Thus, the reaction centers of C. thermophilum have some properties that resemble other homodimeric reaction centers but also have specific properties that are more similar to those of Photosystem I. These differences probably contribute to protection of the electron transfer chain from oxygen, contributing to the oxygen tolerance of this microaerophile.

Severe type 1 upgrading leprosy reaction in a renal transplant recipient: a paradoxical manifestation associated with deficiency of antigen-specific regulatory T-cells?

BACKGROUND: Due to its chronic subclinical course and large spectrum of manifestations, leprosy often represents a diagnostic challenge. Even with proper anti-mycobacteria treatment, leprosy follow up remains challenging: almost half of leprosy patients may develop reaction episodes. Leprosy is an infrequent complication of solid organ transplant recipients. This case report illustrates the challenges in diagnosing and managing leprosy and its reactional states in a transplant recipient. CASE PRESENTATION: A 53-year-old man presented 34 months after a successful renal transplantation a borderline-tuberculoid leprosy with signs of mild type 1 upgrading reaction (T1R). Cutaneous manifestations were atypical, and diagnosis was only made when granulomatous neuritis was found in a cutaneous biopsy. He was successfully treated with the WHO recommended multidrug therapy (MDT: rifampicin, dapsone and clofazimine). However he developed a severe T1R immediately after completion of the MDT but no signs of allograft rejection. T1R results from flare-ups of the host T-helper-1 cell-mediated immune response against Mycobacterium leprae antigens in patients with immunologically unstable, borderline forms of leprosy and has been considered an inflammatory syndrome in many aspects similar to the immune reconstitution inflammatory syndromes (IRS). The T1R was successfully treated by increasing the prednisone dose without modifying the other immunosuppressive drugs used for preventing allograft rejection. Immunological study revealed that the patient had a profound depletion of both in situ and circulating regulatory T-cells and lack of expansion of the Tregs upon M. leprae stimulation compared to T1R leprosy patients without iatrogenic immunosuppression. CONCLUSIONS: Our case report highlights that leprosy, especially in the transplant setting, requires a high degree of clinical suspicion and the contribution of histopathology. It also suggests that the development of upgrading inflammatory syndromes such as T1R can occur despite the sustained immunosuppressors regimen for preventing graft rejection. Our hypothesis is that the well-known deleterious effects of these immunosuppressors on pathogen-induced regulatory T-cells contributed to the immunedysregulation and development T1R.

Age-Dependent Association of TNFSF15/TNFSF8 Variants and Leprosy Type 1 Reaction.

A current major challenge in leprosy control is the prevention of permanent disabilities. Host pathological inflammatory responses termed type 1 reaction (T1R) are a leading cause of nerve damage for leprosy patients. The environmental or inherited factors that predispose leprosy cases to undergo T1R are not known. However, studies have shown an important contribution of host genetics for susceptibility to T1R. We have previously identified variants encompassing the TNFSF15/TNFSF8 genes as T1R risk factors in a Vietnamese sample and replicated this association in a Brazilian sample. However, we failed to validate in Brazilian patients the strong association of TNFSF15/TNFSF8 markers rs6478108 and rs7863183 with T1R that we had observed in Vietnamese patients. Here, we investigated if the lack of validation of these variants was due to age-dependent effects on association using four independent population samples, two from Brazil and two from Vietnam. In the combined analysis across the four samples, we observed a strong association of the TNFSF15/TNFSF8 variants rs6478108, rs7863183, and rs3181348 with T1R (pcombined = 1.5E-05, pcombined = 1.8E-05, and pcombined = 6.5E-06, respectively). However, the association of rs6478108 with T1R was more pronounced in leprosy cases under 30 years of age compared to the global sample [odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.54-2.46, pcombined = 2.5E-08 versus OR = 1.46, 95% CI = 1.23-1.73, pcombined = 1.5E-05]. A multivariable analysis indicated that the association of rs6478108 with T1R was independent of either rs7863183 or rs3181348. These three variants are known regulators of the TNFSF8 gene transcription level in multiple tissues. The age dependency of association of rs6478108 and T1R suggests that the genetic control of gene expression varies across the human life span.

Type 1 Reaction in Patients With Leprosy Corresponds to a Decrease in Proresolving Lipid Mediators and an Increase in Proinflammatory Lipid Mediators.

Background: Type 1 reaction (T1R) is an acute T-helper type 1 (Th1) inflammatory episode in patients with leprosy. While immunological responses associated with T1R have been investigated, the corresponding metabolic responses that could contribute to T1R pathology have received little attention. Methods: Metabolomics-based analyses of sera from 7 patients with and 9 without T1R were conducted via liquid chromatography-mass spectrometry. Serum metabolites present at levels that significantly differed (P < .05) with a log2 fold change of ≥ 1.0 between patient groups were interrogated against known metabolic pathways. The structural identification of targeted metabolites was confirmed and abundance changes validated by mass spectrometry and enzyme-linked immunoassay. Results: Forty metabolic pathways were perturbed in patients with T1R, with 71 dysregulated metabolites mapping to pathways for lipid mediators of inflammation. Of note was an increase in the abundance of the proinflammatory leukotriene B4 (LTB4) and a corresponding decrease in the level of proresolving resolvin D1 (RvD1). Also, levels of prostaglandin D2 (PGD2) and lipoxin A4 (LXA4) in patients with T1R were significantly increased, while the level of prostaglandin E2 (PGE2) was decreased. Conclusions: The dysregulation of metabolic pathways leading to abundance shifts between proinflammatory and proresolving lipid mediators provides a link between metabolic and cellular immune responses that result in the Th1-mediated pathology of T1R.

Type 1 reaction in leprosy: a model for a better understanding of tissue immunity under an immunopathological condition.

Type 1 reaction (T1R) or reversal reaction is the leading cause of physical disabilities and deformities in leprosy. Leprosy patients, even after being considered cured and released from treatment, may suffer from reactional episodes for long periods of time. Early diagnosis is a great challenge for effectively treating and managing T1R. There is an urgent need to identify the most significant biomarkers to prevent recurrent T1R and to differentiate late T1R from relapse. T1R continues to be treated with corticosteroids and complications due to iatrogenic treatment remain frequent. This review aims to provide a framework from which to approach the great challenges that still persist in T1R management and debate key issues in order to reduce the distance between basic research and the clinic.

Association of TNFSF8 regulatory variants with excessive inflammatory responses but not leprosy per se.

BACKGROUND: Type 1 reactions (T1R) affect a considerable proportion of patients with leprosy. In those with T1R, the host immune response pathologically overcompensates for the actual infectious threat, resulting in nerve damage and permanent disability. Based on the results of a genome-wide association study of leprosy per se, we investigated the TNFSF15 chromosomal region for a possible contribution to susceptibility to T1R. METHODS: We performed a high-resolution association scan of the TNFSF15 locus to evaluate the association with T1R in 2 geographically and ethnically distinct populations: a family-based sample from Vietnam and a case-control sample from Brazil, comprising a total of 1768 subjects. RESULTS: In the Vietnamese sample, 47 single-nucleotide polymorphisms (SNPs) overlapping TNFSF15 and the adjacent TNFSF8 gene were associated with T1R but not with leprosy. Of the 47 SNPs, 39 were cis-expression quantitative trait loci (cis-eQTL) for TNFSF8 including SNPs located within the TNFSF15 gene. In the Brazilian sample, 18 of these cis-eQTL SNPs overlapping the TNFSF8 gene were validated for association with T1R. CONCLUSIONS: Taken together, these results indicate TNFSF8 and not TNFSF15 as an important T1R susceptibility gene. Our data support the need for infection genetics to go beyond genes for pathogen control to explore genes involved in a commensurate host response.

Association of TNFSF8 regulatory variants with excessive inflammatory responses but not leprosy per se

BACKGROUND: Type 1 reactions (T1R) affect a considerable proportion of patients with leprosy. In those with T1R, the host immune response pathologically overcompensates for the actual infectious threat, resulting in nerve damage and permanent disability. Based on the results of a genome-wide association study of leprosy per se, we investigated the TNFSF15 chromosomal region for a possible contribution to susceptibility to T1R. METHODS: We performed a high-resolution association scan of the TNFSF15 locus to evaluate the association with T1R in 2 geographically and ethnically distinct populations: a family-based sample from Vietnam and a case-control sample from Brazil, comprising a total of 1768 subjects. RESULTS: In the Vietnamese sample, 47 single-nucleotide polymorphisms (SNPs) overlapping TNFSF15 and the adjacent TNFSF8 gene were associated with T1R but not with leprosy. Of the 47 SNPs, 39 were cis-expression quantitative trait loci (cis-eQTL) for TNFSF8 including SNPs located within the TNFSF15 gene. In the Brazilian sample, 18 of these cis-eQTL SNPs overlapping the TNFSF8 gene were validated for association with T1R. CONCLUSIONS: Taken together, these results indicate TNFSF8 and not TNFSF15 as an important T1R susceptibility gene. Our data support the need for infection genetics to go beyond genes for pathogen control to explore genes involved in a commensurate host response.

Recognizing and managing the immunologic reactions in leprosy.

Immunologic reactions are an important aspect of leprosy that significantly impacts the course of the disease and the associated disability. Reversal reaction (type 1), erythema nodosum leprosum (type 2), and Lucio phenomenon are the 3 leprosy reactions, and they are most commonly seen in patients with the lepromatous and borderline categories of the disease. Because these forms of leprosy are the most common types seen in the United States, it is particularly important for physicians to be able to recognize and treat them. The reactions may occur before, during, or after treatment with multidrug therapy. Reversal reactions are the most common cause of nerve damage in leprosy, and erythema nodosum leprosum may also lead to neuritis. Although there have not been enough studies to confirm the most effective management regimens, treatment of reversal reaction and Lucio phenomenon with prednisone and of erythema nodosum leprosum with thalidomide and/or prednisone may help improve symptoms and prevent further disability.

Epidemiological and clinical patterns of 92 patients co-infected with HIV and Mycobacterium leprae from Rio de Janeiro State, Brazil.

BACKGROUND: Many articles have shown that HIV infection can modify the clinical course of leprosy, but very scant epidemiological and clinical data about this co-infection are available in the peer-reviewed literature. METHODS: We herein describe the geographical distribution and demographic characteristics of 92 HIV/Mycobacterium leprae co-infected patients assisted in a Brazilian Leprosy referral center. A multivariate analysis was performed in order to establish clinical factors associated with type 1 reaction. RESULTS: Co-infected patient admissions have steadily increased over the last years at this referral center. Most patients were men, with a mean age of 32.3 years and presenting with the paucibacillary form of leprosy. The use of antiretroviral therapy (ART) was the only factor associated with type 1 reaction. Most patients were living in the metropolitan area and the north sub area of Rio de Janeiro City. CONCLUSION: Co-infected patients receiving ART have a greater chance to develop type 1 reaction. Patients living with both HIV and leprosy are likely to live in regions characterized by a high density impoverished population.