Adverse reactions induced by MDT/WHO (Rifampicin+Clofazimine+Dapsone) and ROM (Rifampicin+Ofloxacin+Minocycline) regimens used in the treatment of leprosy: a cohort study in a National Reference Center in Brazil.

Background: Recommended standard treatment for leprosy is multidrugtherapy (MDT/WHO), consisting Rifampicin+Dapsone+Clofazimine. Other medications are recommended in cases of resistance, adverse reactions and intolerances, including ROM regimen, Rifampicin+Ofloxacin+Minocycline. Therefore, pharmacovigilance is an important tool in understanding these adverse drug reactions (ADRs), supporting pharmacotherapy management and medication safety. This study seeks to evaluate ADRs comparing two therapeutic regimens, MDT and ROM, used in treatment of patients with leprosy, analyzing prognostic factors regarding risk and safety. Methods:A retrospective cohort study was performed by assessing medical records of 433 patients diagnosed with leprosy from 2010 to 2021 at a National Reference Center in Brazil. They were subject to 24 months or more of treatment with MDT or ROM regimens. ADR assessments were analyzed by two experienced researchers, who included clinical and laboratory variables, correlating them with temporality, severity and the causality criteria of Naranjo and WHO. Results: The findings observed an average of 1.3 reactions/patient. Out of individuals experiencing reactions, 67.0% (69/103) were utilizing MDT/MB, while 33.0% (34/103) were using ROM. The median time for ADR of 79 days for MDT and 179 days for ROM. In first reaction, Dapsone was the most frequently involved medication; the most affected system was hematopoietic. As compared to Clofazimine, results indicated that use of Dapsone was associated with 7% increased risk of ADR occurrence (HR: 1.07; p = 0.866). Additionally, Rifampicin was linked to 31% increased risk of ADRs (HR: 1.31; p = 0.602); and Ofloxacin showed 35% elevated risk (HR: 1.35; p = 0.653). Conversely, results for Minocycline indicated 44% reduction in the risk of ADRs (HR: 0.56; p = 0.527), although statistical significance was not reached. The use of MDT conferred 2.51 times higher risk of developing ADRs in comparison to ROM. Conclusion: The comparison between MDT and ROM revealed that MDT caused more ADRs, and these reactions were more severe, indicating less safety for patients. Dapsone was the most common medication causing ADRs, followed by Rifampicin. The combination with Clofazimine was associated with an additional risk of ADRs, warranting further studies to confirm this hypothesis. Given the high magnitude of ADRs, healthcare teams need to monitor patients undergoing leprosy treatment with focus on pharmacovigilance.

Bartonella henselae as a putative trigger for chronic type 2 leprosy reactions.

Leprosy reactions are an acute inflammatory phenomenon that can arise before diagnosis, during treatment, or after cure of leprosy. These reactions are considered one of the main diseases that cause physical disabilities. Immunosuppressive treatment for these immune responses makes these patients susceptible to coinfections, which can trigger new leprosy reactions. The main objective of this study was to evaluate the occurrence of infection by Bartonella sp. in blood samples from 47 patients who had untreatable episodes of type 2 leprosy reactions for more than six months, comparing them with a control group. Cultures and molecular methods (PCR) were used. Amplicons from species-specific reactions and sequencing showed a higher prevalence of Bartonella henselae infection in patients, 19/47 (40.4 %), compared to control, 9/50 (18.0 %), p = 0.0149. Five patients accepted treatment for coinfection, and all showed improvement in leprosy reactions with treatment for B. henselae infection. We conclude that these bacteria can trigger chronic reactions of type 2 leprosy and should be investigated in these patients. SUMMARY LINE: Patients who have chronic type 2 leprosy reactions are more susceptible to Bartonella henselae infection than controls: 19/47 (40.4 %) compared 9/50 (18.0 %), p = 0.0149.

HSP60 mimetic peptides from Mycobacterium leprae as new antigens for immunodiagnosis of Leprosy.

The early diagnosis of leprosy serves as an important tool to reduce the incidence of this disease in the world. Phage display (PD) technology can be used for mapping new antigens to the development of immunodiagnostic platforms. Our objective was to identify peptides that mimic Mycobacterium leprae proteins as serological markers using phage display technology. The phages were obtained in the biopanning using negative and positive serum from household contacts and leprosy patients, respectively. Then, the peptides were synthesized and validated in silico and in vitro for detection of IgG from patients and contacts. To characterize the native protein of M. leprae, scFv antibodies were selected against the synthetic peptides by PD. The scFv binding protein was obtained by immunocapture and confirmed using mass spectrometry. We selected two phase-fused peptides, MPML12 and MPML14, which mimic the HSP60 protein from M. leprae. The peptides MPML12 and MPML14 obtained 100% and 92.85% positivity in lepromatous patients. MPML12 and MPM14 detect IgG, especially in the multibacillary forms. The MPML12 and MPML14 peptides had positivity of 11.1% and 16.6% in household contacts, respectively. There was no cross-reaction in patient's samples with visceral leishmaniasis, tuberculosis and other mycobacteriosis for both peptides. Given these results and the easy obtainment of mimetic antigens, our peptides are promising markers for application in the diagnosis of leprosy, especially in endemic and hyperendemic regions.

High-resolution ultrasonography for early diagnosis of neural impairment in seropositive leprosy household contacts.

Leprosy household contacts (HC) represent a high-risk group for the development of the disease. Anti-PGL-I IgM seropositivity also increases the risk of illness. Despite significant advances in leprosy control, it remains a public health problem; and early diagnosis of this peripheral neuropathy represents one of the main goals of leprosy programs. The present study was performed to identify neural impairment in leprosy HC by analyzing differences in high-resolution ultrasonographic (US) measurements of peripheral nerves between leprosy HC and healthy volunteers (HV). Seventy-nine seropositive household contacts (SPHC) and 30 seronegative household contacts (SNHC) underwent dermato-neurological examination and molecular analysis, followed by high-resolution US evaluation of cross-sectional areas (CSAs) of the median, ulnar, common fibular and tibial nerves. In addition, 53 HV underwent similar US measurements. The US evaluation detected neural thickening in 26.5% (13/49) of the SPHC and only in 3.3% (1/30) among the SNHC (p = 0.0038). The CSA values of the common fibular and tibial nerves were significantly higher in SPHC. This group also had significantly greater asymmetry in the common fibular and tibial nerves (proximal to the tunnel). SPHC presented a 10.5-fold higher chance of neural impairment (p = 0.0311). On the contrary, the presence of at least one scar from the BCG vaccine conferred 5.2-fold greater protection against neural involvement detected by US (p = 0.0184). Our findings demonstrated a higher prevalence of neural thickening in SPHC and support the role of high-resolution US in the early diagnosis of leprosy neuropathy. The combination of positive anti-PGL-I serology and absence of a BCG scar can identify individuals with greater chances of developing leprosy neuropathy, who should be referred for US examination, reinforcing the importance of including serological and imaging methods in the epidemiological surveillance of leprosy HC.

Early diagnosis of neural impairment in seropositive leprosy household contacts: The experience of a reference center in Brazil.

Introduction: Leprosy is an infectious disease that remains with a high number of new cases in developing countries. Household contacts have a higher risk for the development of the disease, but the neural impairment in this group is not well elucidated yet. Here, we measured the chance of occurrence of peripheral neural impairment in asymptomatic leprosy household. Methods: Contacts who present anti-PGL-I IgM seropositivity, through electroneuromyography (ENMG) evaluation. We recruited 361 seropositive contacts (SPC) from 2017 to 2021, who were subjected to an extensive protocol that included clinical, molecular, and electroneuromyographic evaluations. Results: Our data revealed a positivity of slit skin smear and skin biopsy qPCR of 35.5% (128/361) and 25.8% (93/361) respectively. The electroneuromyographic evaluation of the SPC showed neural impairment in 23.5% (85/361), with the predominance of a mononeuropathy pattern in 62.3% (53/85). Clinical neural thickening was observed in 17.5% (63/361) of seropositive contacts, but among the individuals with abnormal ENMG, only 25.9% (22/85) presented neural thickening in the clinical exam. Discussion: Ours results corroborates the need to make the approach to asymptomatic contacts in endemic countries more timely. Since leprosy in its early stages can present an indolent and subclinical evolution, serological, molecular, and neurophysiological tools are essential to break the disease transmission chain.

Description of electroneuromiographic and laboratorial findings in leprosy neuropathy, according to its clinical forms: the confirmation of a spectral disease.

Introduction: Leprosy is one of the most common infectious cause of peripheral neuropathy in the world and can lead to sequelae and physical disabilities. Electroneuromyography (ENMG) is the gold-standard test for evaluating neural impairment, detecting from subclinical abnormalities to advanced lesions. This study aims to describe the electroneuromyographic findings in patients with leprosy, according to their clinical forms. Methods: The study is a retrospective observational analysis of the medical records of patients with leprosy, of a National Reference Center of Sanitary Dermatology and Leprosy in Brazil between 2014 and 2022. 513 patients underwent ENMG at leprosy diagnosis and also underwent a clinical, serological and molecular evaluation of the disease. Results: The electroneuromyographic findings showed 2,671 altered nerves, with an average of 6.9 (±5.1) altered nerves per patient. The most affected sensory nerves were the superficial peroneal (25.0%; 413/1649), sural (15.1%; 397/2627) and ulnar (13.8%; 363/2627), with average of 4.3 (±3.2) affected sensory nerves per patient. The most affected motor nerves were the ulnar (33.1%; 338/1022) and common peroneal (12.1%; 319/2627), with average of 2.6 (±2.5) motor nerves affected per patient. 126 patients presented normal ENMG and, among the 387 with abnormalities in the exam, 13.2% (51/387) had mononeuropathy and 86.8% (336/387) had multiple mononeuropathy. Axonal involvement was more frequent in primary neural leprosy, borderline-tuberculoid, borderline-lepromatous and lepromatous forms. Discussion: Our findings support that leprosy is a spectral disease, characterized by a balance between host immunity and bacillary load. Therefore, the impairment and electroneuromyographic characteristics are distinct and may vary according to the clinical form.

Bartonella henselae as a putative trigger for chronic type 2 leprosy reactions

Abstract Leprosy reactions are an acute inflammatory phenomenon that can arise before diagnosis, during treatment, or after cure of leprosy. These reactions are considered one of the main diseases that cause physical disabilities. Immunosuppressive treatment for these immune responses makes these patients susceptible to coinfections, which can trigger new leprosy reactions. The main objective of this study was to evaluate the occurrence of infection by Bartonella sp. in blood samples from 47 patients who had untreatable episodes of type 2 leprosy reactions for more than six months, comparing them with a control group. Cultures and molecular methods (PCR) were used. Amplicons from species-specific reactions and sequencing showed a higher prevalence of Bartonella henselae infection in patients, 19/47 (40.4 %), compared to control, 9/50 (18.0 %), p= 0.0149. Five patients accepted treatment for coinfection, and all showed improvement in leprosy reactions with treatment for B. henselae infection. We conclude that these bacteria can trigger chronic reactions of type 2 leprosy and should be investigated in these patients. Summary line Patients who have chronic type 2 leprosy reactions are more susceptible to Bartonella henselae infection than controls: 19/47 (40.4 %) compared 9/50 (18.0 %), p= 0.0149.

Clinical, epidemiological, and laboratory prognostic factors in patients with leprosy reactions: A 10-year retrospective cohort study.

Introduction: Leprosy reactions, the main cause of neural damage, can occur up to 7 years after starting multidrug therapy. We aimed to approach the prognostic factors that may influence the leprosy reactions over the follow-up time. Methods: Retrospective cohort study, encompassing 10 years of data collection, composed of 390 patients, divided into 201 affected by reactions and 189 reaction-free individuals. Epidemiological, clinical, and laboratory variables were approached as prognostic factors associated with leprosy reactions. The association among variables was analyzed by a binomial test and survival curves were compared by the Kaplan-Meier and Cox proportional-hazards regression. Results: 51.5% (201/390) of patients were affected by leprosy reactions. These immunological events were associated with lepromatous leprosy (16.2%; 63/390; p < 0.0001) and multibacillary group (43%; 169/390; p < 0.0001). This study showed that survival curves for the prognostic factor anti-PGL-I, comparing positive and negative cases at diagnosis, differed in relation to the follow-up time (Log Rank: p = 0.0760; Breslow: p = 0.0090; Tarone-Ware: p = 0.0110). The median survival times (time at which 50% of patients were affected by leprosy reactions) were 5 and 9 months for those reactional cases with negative (26/51) and positive serology (75/150), respectively. The time-dependent covariates in the cox proportional-hazards regression showed anti-PGL-I as the main prognostic factor to predict leprosy reactions (hazard ratio=1.91; p = 0.0110) throughout the follow-up time. Conclusions: Finally, these findings demonstrated that anti-PGL-I serology at diagnosis is the most important prognostic factor for leprosy reactions after starting multidrug therapy, thus enabling prediction of this immunological event.

Fever of Unknown Origin, Wasting Syndrome and Bone Marrow Involvement: A Leprosy Case Report.

Mycobacterium leprae, the etiologic agent of leprosy, is an acid-fast-staining and slow-growing bacilli that infect macrophages and Schwann cells individually or through forming globi. The clinical presentation of leprosy is broad and depends on the host immune response. We report a case of a 42-year-old Brazilian man presenting with fever of unknown origin (FUO), anemia, wasting syndrome, and neuropathy. The diagnosis of lepromatous leprosy was made after an extensive investigation revealed the presence of M. leprae in the bone marrow. Bone marrow involvement in leprosy is rare and some authors believe the presence of M. leprae in the bone marrow can act as a reservoir of the disease facilitating future relapses. It is important to investigate bone marrow involvement in leprosy, especially when the patient presents with cytopenias and positive epidemiologic history.

Leprosy Relapse: A Retrospective Study on Epidemiologic, Clinical, and Therapeutic Aspects at a Brazilian Referral Center.

OBJECTIVES: We aimed to characterize the profile of patients diagnosed with leprosy relapse and understand the influence of different multidrug therapy (MDT) treatments and initial disease presentation. METHODS: This retrospective study included patients diagnosed with leprosy relapse at a referral center in Brazil from 2013 to 2018. We analyzed their clinico-epidemiologic characteristics, laboratory data, and bacilloscopic tests. Survival analysis was used to determine the time elapsed until relapse according to the previous treatment and clinical forms of the disease. RESULTS: A total of 126 cases of relapse were analyzed, which comprised 11.89% (126/1059) of the cases. The median time elapsed until a relapse was 10 years, and most patients had previously undergone 12 doses of MDT (40.48%; 51/126). Undergoing 24 doses of MDT was associated with a better prognosis regarding relapse over time compared with 6 or 12 doses of MDT therapy. Most cases of relapse were classified as multibacillary (96.03%; 121/126). CONCLUSION: The incidence of relapse was greater than observed in other studies. The high percentage of multibacillary patients who had negative bacillary indices demonstrated that the bacillary index cannot be considered to be an essential criterion for relapse, especially concerning making an early diagnosis.

Type 2 leprosy reaction presenting as a monoarthritis post multidrug therapy.

Type 2 leprosy reaction, or erythema nodosum leprosum (ENL), involves a complex interaction between the host's immune system and Mycobacterium leprae. It may occur before, during, or after treatment and have a variable clinical presentation involving different body systems, such as skin, osteoarticular, kidneys, and others. Thus, the differential diagnosis, depending on its clinical presentation, can be broad and challenging. The authors report a case of a severe monoarthritis during a type 2 reaction after the multidrug therapy (MDT) was discharged and the investigation of the differential diagnoses.

Late follow-up of peripheral neural decompression in leprosy: functional and clinical outcomes.

BACKGROUND: Peripheral neural surgical decompression (PNSD) is used as a complementary therapy to the clinical treatment of neuritis to preserve neural function. OBJECTIVE: To evaluate the long-term (≥ 1 year) clinical and functional results for PNSD in leprosy neuritis. METHODS: This cross-sectional study included leprosy patients who were in late postoperative period (LPO) of surgical decompression of ulnar, median, tibial, and fibular nerves. Socioeconomic, epidemiological, and clinical data were collected. The following instruments were used in this evaluation: visual analogue pain scale (VAS), Douleur Neuropathique en 4 Questions (DN4), SALSA scale, and simplified neurological assessment protocol. The preoperative (PrO) and 180-day postoperative (PO180) results were compared. RESULTS: We evaluated 246 nerves from 90 patients: 56.6% were on multidrug therapy (MDT) and 43.3% discharged from MDT. Motor scores and pain intensity showed statistically significant improvement (p<0.01). There was an increase in sensory scores only for bilateral ulnar nerves (p<0.05). Of the operated cases, 26.0% of patients were referred for surgery of ulnar neuritis and 23.6% of tibial neuritis. Neuropathic pain was reported in 41% of cases. Daily dose of prednisone reduced from 39.6 mg (±3.0) in PrO, 16.3 mg (±5.2) in PO180, to 1.7 mg (±0.8) in LPO. The SALSA scale results showed mild activity limitation in 51% and moderate in 34% of patients. Eighty percent of individuals reported that the results reached their expectations. CONCLUSIONS: PNSD in leprosy was effective in the long term to decrease the prevalence and intensity of pain, improve motor function, and reduce the dose of corticosteroids, which is reflected in the patients' satisfaction.

Assessment of neuropathic pain in leprosy patients with relapse or treatment failure by infrared thermography: A cross-sectional study.

BACKGROUND: Neuropathic pain (NP) is one of the main complications of leprosy, and its management is challenging. Infrared thermography (IRT) has been shown to be effective in the evaluation of peripheral autonomic function resulting from microcirculation flow changes in painful syndromes. This study used IRT to map the skin temperature on the hands and feet of leprosy patients with NP. METHODOLOGY/PRINCIPAL FINDINGS: This cross-sectional study included 20 controls and 55 leprosy patients, distributed into 29 with NP (PWP) and 26 without NP (PNP). Thermal images of the hands and feet were captured with infrared camera and clinical evaluations were performed. Electroneuromyography (ENMG) was used as a complementary neurological exam. Instruments used for the NP diagnosis were visual analog pain scale (VAS), Douleur Neuropathic en 4 questions (DN4), and simplified neurological assessment protocol. The prevalence of NP was 52.7%. Pain intensity showed that 93.1% of patients with NP had moderate/severe pain. The most frequent DN4 items in individuals with NP were numbness (86.2%), tingling (86.2%) and electric shocks (82.7%). Reactional episodes type 1 were statistically significant in the PWP group. Approximately 81.3% of patients showed a predominance of multiple mononeuropathy in ENMG, 79.6% had sensory loss, and 81.4% showed some degree of disability. The average temperature in the patients' hands and feet was slightly lower than in the controls, but without a significant difference. Compared to controls, all patients showed significant temperature asymmetry in almost all points assessed on the hands, except for two palmar points and one dorsal point. In the feet, there was significant asymmetry in all points, indicating a greater involvement of the lower limbs. CONCLUSION: IRT confirmed the asymmetric pattern of leprosy neuropathy, indicating a change in the function of the autonomic nervous system, and proving to be a useful method in the approach of pain.

Late follow-up of peripheral neural decompression in leprosy: functional and clinical outcomes / Seguimento tardio da descompressão neural periférica na hanseníase: resultados funcionais e clínicos

ABSTRACT Background: Peripheral neural surgical decompression (PNSD) is used as a complementary therapy to the clinical treatment of neuritis to preserve neural function. Objective: To evaluate the long-term (≥ 1 year) clinical and functional results for PNSD in leprosy neuritis. Methods: This cross-sectional study included leprosy patients who were in late postoperative period (LPO) of surgical decompression of ulnar, median, tibial, and fibular nerves. Socioeconomic, epidemiological, and clinical data were collected. The following instruments were used in this evaluation: visual analogue pain scale (VAS), Douleur Neuropathique en 4 Questions (DN4), SALSA scale, and simplified neurological assessment protocol. The preoperative (PrO) and 180-day postoperative (PO180) results were compared. Results: We evaluated 246 nerves from 90 patients: 56.6% were on multidrug therapy (MDT) and 43.3% discharged from MDT. Motor scores and pain intensity showed statistically significant improvement (p<0.01). There was an increase in sensory scores only for bilateral ulnar nerves (p<0.05). Of the operated cases, 26.0% of patients were referred for surgery of ulnar neuritis and 23.6% of tibial neuritis. Neuropathic pain was reported in 41% of cases. Daily dose of prednisone reduced from 39.6 mg (±3.0) in PrO, 16.3 mg (±5.2) in PO180, to 1.7 mg (±0.8) in LPO. The SALSA scale results showed mild activity limitation in 51% and moderate in 34% of patients. Eighty percent of individuals reported that the results reached their expectations. Conclusions: PNSD in leprosy was effective in the long term to decrease the prevalence and intensity of pain, improve motor function, and reduce the dose of corticosteroids, which is reflected in the patients' satisfaction.

RESUMO Antecedentes: A descompressão cirúrgica neural periférica (DCNP) é usada como uma terapia complementar ao tratamento clínico da neurite hansênica para preservar a função neural. Objetivo: Avaliar a longo prazo (≥ 1 ano) os resultados clínicos e funcionais da DCNP na neurite hansênica. Métodos: Este estudo transversal incluiu pacientes que estavam no pós-operatório tardio (POT) de cirurgia de descompressão dos nervos ulnares, medianos, tibiais e fibulares. Foram coletados dados socioeconômicos, epidemiológicos e clínicos. Os instrumentos utilizados foram: escala visual analógica de dor (EVA), questionário de dor neuropática 4 (DN4), escala SALSA e protocolo de avaliação neurológica simplificada. Os resultados obtidos foram comparados com os do pré-operatório (PrO) e pós-operatório de 180 dias (PO180). Resultados: Foram avaliados 246 nervos de 90 pacientes: 56,6% estavam em poliquimioterapia (PQT) e 43,3% em alta da PQT. Escores motores e intensidade da dor apresentaram melhora significante (p<0,01). Houve aumento nos escores sensitivos nos nervos ulnares bilaterais (p<0,05). Neurite ulnar foi indicação cirúrgica em 26,0% dos casos operados, seguida pela neurite tibial (23,6%). Dor neuropática foi relatada em 41% dos casos. Dose diária de prednisona reduziu de 39,6 mg (±3,0) na PrO, 16,3 mg (±5,2) na PO180, para 1,7 mg (±0,8) na POT. Escala SALSA mostrou limitação leve da atividade em 51% e moderada em 34% dos pacientes. 80% dos indivíduos relataram que os resultados atingiram suas expectativas. Conclusão: DCNP na hanseníase foi eficaz a longo prazo na redução da prevalência e intensidade da dor, na melhora da função motora e redução da dose de corticosteroides, refletindo na satisfação do paciente.

Peripheral nerve biopsy: a tool still needed in the early diagnosis of neural leprosy?

BACKGROUND: The early recognition of neural impairment in leprosy, especially in primary neural forms, represents a challenge in clinical practice and a peripheral nerve biopsy may be required for diagnostic confirmation. This study aims to characterize the epidemiological, clinical, electroneuromyographic, laboratory and histopathological aspects of patients undergoing peripheral nerve biopsy during investigation of primary neural cases in leprosy. METHODS: A total of 104 patients with peripheral neuropathy who were referred to a national reference centre for leprosy were biopsied from 2014 to 2018. All cases underwent clinical, laboratory, histopathological and electroneuromyographic evaluations. RESULTS: Of 104 biopsied patients, leprosy was confirmed in 89.4% (93/104). The biopsied nerves were the ulnar (67.8% [63/93]), superficial fibular (21.5% [20/93]), sural (8.6% [8/93]), radial (1.1% [1/93]) and deep fibular (1.1% [1/93]). Twenty-nine percent (27/93) presented histopathological abnormalities and 4.4% (4/93) presented acid-fast bacilli. Nerve and superjacent skin quantitative polymerase chain reaction were positive in 49.5% (46/93) and 24.8% (23/93) of cases, respectively. Patients with multiple mononeuropathy had a higher frequency of histopathological abnormalities (p=0.0077). CONCLUSIONS: This study reinforces peripheral nerve biopsy's role as an important tool in the investigation of primary neural cases, contributing to the early diagnosis and also reducing diagnostic errors and the need for empirical treatment.

Biotechnological and Immunological Platforms Based on PGL-I Carbohydrate-Like Peptide of Mycobacterium leprae for Antibodies Detection Among Leprosy Clinical Forms.

Phenolic glycolipid I (PGL-I) is an abundant antigen on the Mycobacterium leprae cell wall, commonly used for operational classification of leprosy patients. Our aim was to develop PGL-I mimotopes with similar characteristics and functions of the native antigen. We have used a random peptide phage display (PD) library for selections against the monoclonal antibody anti-PGL-I. After three selection cycles, six peptides were identified. All sequences were interspersed by a spacer generating a chimeric peptide (PGLI-M3) that was artificially synthesized. The highly reactive peptide was submitted to a reverse PD selection with a single-chain Fv (scFv) antibody fragment combinatorial library. The most reactive scFv was then validated by enzyme-linked immunosorbent assay (ELISA) against both native PGL-I and two derived synthetic (NDO and ND-O-HSA). We have further proved the scFv specificity by detecting M. leprae bacilli in leprosy lesions through immunohistochemistry. We then described its applicability in ELISA for all clinical forms and household contacts (HC). Afterward, we showed differential binding affinities of PGLI-M3 to sera (anti-PGL-I IgM) from all leprosy clinical forms through surface plasmon resonance (SPR). ELISA IgM detection showed 89.1% sensitivity and 100% specificity, considering all clinical forms. Positivity for anti-PGL-I IgM was twofold higher in both HC and patients with paucibacillary forms in hyperendemic regions than in endemic ones. The SPR immunosensor was able to differentiate clinical forms with 100% accuracy. This is the first time that a PGL-I mimotope has efficiently mimicked the carbohydrate group of the M. leprae antigen with successful immunoassay applications and may become a substitute for the native antigen.

Differential Expression of IFN-γ, IL-10, TLR1, and TLR2 and Their Potential Effects on Downgrading Leprosy Reaction and Erythema Nodosum Leprosum.

Leprosy reactions are acute immunological events that occur during the evolution of chronic infectious disease causing neural damage and disabilities. A study using blood samples of 17 leprosy reaction patients and 17 reaction-free was carried out by means of associations between antigens, receptors, and expression of cytokines, using path analysis providing new insights into the immunological mechanisms involved in triggering leprosy reactions. Toll-like receptors (TLR) such as TLR1 and TLR2, presented balanced expression in the reaction-free multibacillary (MB) group (TLR1: 1.01 ± 0.23, TLR2: 1.22 ± 0.18; p = 0.267). On the other hand, downgrading type 1 reaction (T1R) (TLR1: 1.24 ± 0.17, TLR2: 2.88 ± 0.37; p = 0.002) and erythema nodosum leprosum (ENL) (TLR1: 1.93 ± 0.17, TLR2: 2.81 ± 0.15; p = 0.004) revealed an unbalance in relation to the expression of these receptors. When the path analysis was approached, it was noted that interleukin 10 (IL-10) expression showed a dependence relation with phenolic glycolipid I (PGL-I) in downgrading T1R (direct effect = 0.503 > residual effect = 0.364), whereas in ENL, such relationship occurred with lipoarabinomannan (LAM) (direct effect = 0.778 > residual effect = 0.280). On the contrary, in the reaction-free leprosy group, interferon-gamma (IFN-γ) levels were dependent on the association between TLR2 and TLR1 (0.8735). The high TLR2 expression associated with IL-10 levels, in the leprosy reaction groups, may be hypothetically related to the formation of TLR2/2 homodimers and/or TLR2/6 heterodimers linked to evasion mechanisms in downgrading reactions and pathophysiology of ENL.

BCG vaccine and leprosy household contacts: Protective effect and probability to becoming sick during follow-up.

BACKGROUND: Immunoprophylaxis with Bacillus Calmette-Guérin (BCG) vaccine is still the most effective intervention in the prevention of leprosy among household contacts (HHCs) of leprosy patients. METHODS: A retrospective cohort study using data of 5.061 HHCs for a period of 16 years (follow-up of 7 years per leprosy HHCs), evaluating the occurrence of disease as the main outcome and the presence or absence of BCG scars verified at the first evaluation. Statistical analyzes were performed using the relative risk, hazard ratio and survival curves by Kaplan-Meier test. RESULTS: A total of 92 contacts sickened, of which 41.3% (38/92) in the first year and 58.7% (54/92) in the course of the other years of follow-up. Of those who became sick, 62% (57/92) developed borderline tuberculoid (BT). The additional protective effect occurred for those who had 2 BCG scars at the first follow-up assessment (Relative Risk: 0.41; p = 0.007) when compared to those not previously exposed to the vaccine. The number of BCG scars examined at the first assessment (t0 = time zero) affected the occurrence of the outcome evidenced by the difference in survival curves throughout the follow-up (Log Rank, p = 0.041; Breslow, p = 0.012; Tarone-Ware, p = 0.020). Leprosy HHCs with 0 BCG scar at time zero (t0) have a shorter survival time (average time of 22 months between t0 and outcome) when compared to those with 2 BCG scars (average time of 36 months between t0 and outcome). CONCLUSIONS: Vaccination of healthy individuals without signs and symptoms of leprosy is extremely important because BCG vaccine has an additional protective effect in those cases with 2 BCG scars throughout follow-up. Reducing the risk of leprosy HHCs becoming sick depends on preventive actions such as immunoprophylaxis and index cases treatment.