Leprosy

Any resurgence of leprosy cases in the Togo's post-elimination period? Trend analysis of reported leprosy cases from 2010 to 2022

BACKGROUND

Leprosy, or Hansen's disease, is a chronic infectious disease caused by Mycobacterium leprae. Togo achieved the target of eliminating leprosy as a public health problem in 2000 (less than 1 case/10 000 population). However, new cases of leprosy are still being reported. The aim of this study was to describe and map trends of leprosy cases notified in Togo from 2010 to 2022.

METHODS

This was a descriptive cross-sectional study covering a thirteen-year period from January 1, 2010, to December 31, 2022. The data of the study were leprosy surveillance system's data collected monthly between 2010 and 2022. The estimated number of leprosy cases and the incidence rate of leprosy cases were reported for the whole population by region, by district, by calendar year (2010-2022) and by target sub-population (children under 15, women and people with disabilities). Observed case incidence rates were mapped by health district and by year.

RESULTS

From January 1, 2010, to December 31, 2022, 1031 new cases of leprosy were diagnosed in Togo. The median age of subjects was 46 years (interquartile range: 33-60), with extremes from 4 to 96 years. Half the subjects were women (50.7%). Variations in the leprosy incidence rate by year show an increase between 2010 and 2022, from 0.7 cases /100,000 population to 1.1 /100,000 population respectively. From 2010 to 2022, the proportion of cases in children remained low, between 0 and 9%. The proportion of women fluctuated between 39.7% and 67.2% between 2010 and 2017, then stabilized at an average of 50% between 2018 and 2022. The proportion of multi-bacillary leprosy cases increased quasi-linearly between 2010 and 2022, from 70 to 96.6%. Mapping of leprosy cases showed that leprosy was notified in all Togo health districts during the study period, apart from the Lacs district, which reported no leprosy cases.

CONCLUSION

Togo has achieved the elimination of leprosy as a public health problem. However, the increase in the number of new leprosy cases and the proportion of leprosy cases in children indicate that transmission of the disease is continuing and that supplementary measures are needed.

Assessing Nerve Conduction Velocity as a Diagnostic and Prognostic Indicator in Leprosy Patients: A Cross-Sectional Study

Introduction Hansen's disease is a condition in which patients develop peripheral neuropathy. In 1873, G. H. A. Hansen discovered Mycobacterium leprae, the causative agent of leprosy, a chronic infectious disease. These bacteria influence the peripheral nerves, which is likely to cause neuropathy. Sensory nerve conduction studies were performed in leprosy patients on the upper limb nerves of 30 patients in the rural area of the Wardha district in the Indian population. Methods In this study, we recruited 30 leprosy patients from the Department of Dermatology and A.V.B.R. Hospital, Sawangi Wardha. The patient's nerve conduction velocity (NCV) tests were carried out in the Department of Physiology at J. N. Medical College, Wardha. NCVs were obtained during these three years, beginning in 2009, while performing sensory nerve conduction velocity (SNCV) and motor nerve conduction velocity (MNCV). The latency, amplitude, and NCV parameters were recorded, and the data collection period ended in 2011. In this study, we measured both MNCV and SNCV. Results In our study, impairment of conductional velocity was observed. In leprosy patients, the MNCV values of latency, amplitude, and conductional velocity were 6.61, 3.89, and 46.92 m/s, respectively, whereas the SNCV values were 3.005, 25.17, and 38 m/s, respectively. Based on the results, it appears that the maximal sensory nerve involvement was recorded at 38 m/s conductional velocity. In NCVs, increased latency and decreased conductional velocity were found across the study. Conclusion It was concluded that nerve conduction studies are one of the non-invasive techniques for early diagnosis and management of leprosy. This study should be repeated with a larger sample size and should be multicentric.

Epidemiology and grade 2 disability of leprosy among migrant and resident patients in Guangdong: an unignorable continued transmission of leprosy

Introduction

Leprosy remains a major public health concern worldwide and one of the leading causes of disability. New cases of leprosy with grade 2 disability (G2D) often reflect delayed detection due to the limited capacity of the health system to recognize leprosy early. This study aimed to describe the epidemiology and G2D of leprosy among migrant and resident patients with leprosy in Guangdong province, China.

Methods

Data on newly diagnosed cases of leprosy were collected from the leprosy management information system in China. Descriptive statistical analysis was used to describe the status of G2D. Joinpoint regression model and logistic regression were performed to analyze the temporal trends and influencing factors for G2D.

Results

The G2D rate among migrant, resident, and total patients with leprosy was 17.5%, 18.7%, and 18.4%, respectively. The total G2D rate increased significantly from 18.0% in 2001 to 25.7% in 2021 (average annual per cent change: 2.5%). Multivariate analysis revealed that factors that negatively influence G2D between migrant and resident patients included delayed discovery time (migrants: OR = 2.57; residents: OR = 4.99) and nerve damage when diagnosed (migrants: OR = 9.40; residents: OR = 21.28).

Discussion

Our findings indicate that the targeted intervention measures implemented by our health system are urgently needed to improve the current situation, such as programs to promote early detection, strengthen awareness and skills of healthcare workers, and rehabilitation for disabled patients to improve their quality of life.

CD11b+Gr-1low cells that accumulate in M.leprae-induced granulomas of the footpad skin of nude mice have the characteristics of monocytic-myeloid-derived suppressor cells

CD11b⁺Gr-1^low cells that are increased in the lungs of a Mycobacterium (M) tuberculosis-infection mouse model have the characteristics of monocytic (M)-myeloid-derived suppressor cells (MDSCs) and harbor M.tuberculosis. Interestingly, a high number of M-MDSCs have also been observed in skin lesions of patients with lepromatous leprosy. We hypothesized that CD11b⁺Gr-1^low cells might be involved in the pathogenesis of leprosy, as they are in tuberculosis. In the current study, we investigated the issue of whether CD11b⁺Gr-1^low cells accumulate in Mycobacterium (M) leprae-induced granulomas of the footpad skin of nude mice. Our results show that CD11b⁺Gr-1^low cells began to accumulate in the 7-month-old M.leprae-induced granulomas and were replaced by other leukocytes, including CD11b⁺Gr-1^high over time during M.leprae infections. CD11b ⁺ Gr-1^low cells expressed the surface markers of M-MDSC, Ly6C^high and Ly6G^low. In addition, CD11b⁺Gr-1^low cells have the nuclei of a mononuclear cell type and expressed higher levels of arginase 1 (Arg1) and inducible NO synthetase (iNOS). Furthermore, they showed a higher infection rate by M.leprae. Taken together, our results indicate that the inoculation with M.leprae induced an accumulation of CD11b ⁺ Gr-1^low at a relatively early stage, 7-month-old M.leprae-induced granulomas, and that CD11b⁺Gr-1^low have the characteristics of M-MDSC and may act as a reservoir for M.leprae.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

LIMITATIONS

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

CONCLUSION

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

Non-Coding RNAs in the Etiology and Control of Major and Neglected Human Tropical Diseases

Non-coding RNAs (ncRNAs) including microRNAs (miRs) and long non-coding RNAs (lncRNAs) have emerged as key regulators of gene expression in immune cells development and function. Their expression is altered in different physiological and disease conditions, hence making them attractive targets for the understanding of disease etiology and the development of adjunctive control strategies, especially within the current context of mitigated success of control measures deployed to eradicate these diseases. In this review, we summarize our current understanding of the role of ncRNAs in the etiology and control of major human tropical diseases including tuberculosis, HIV/AIDS and malaria, as well as neglected tropical diseases including leishmaniasis, African trypanosomiasis and leprosy. We highlight that several ncRNAs are involved at different stages of development of these diseases, for example miR-26-5p, miR-132-3p, miR-155-5p, miR-29-3p, miR-21-5p, miR-27b-3p, miR-99b-5p, miR-125-5p, miR-146a-5p, miR-223-3p, miR-20b-5p, miR-142-3p, miR-27a-5p, miR-144-5p, miR-889-5p and miR-582-5p in tuberculosis; miR-873, MALAT1, HEAL, LINC01426, LINC00173, NEAT1, NRON, GAS5 and lincRNA-p21 in HIV/AIDS; miR-451a, miR-let-7b and miR-106b in malaria; miR-210, miR-30A-5P, miR-294, miR-721 and lncRNA 7SL RNA in leishmaniasis; and miR-21, miR-181a, miR-146a in leprosy. We further report that several ncRNAs were investigated as diseases biomarkers and a number of them showed good potential for disease diagnosis, including miR-769-5p, miR-320a, miR-22-3p, miR-423-5p, miR-17-5p, miR-20b-5p and lncRNA LOC152742 in tuberculosis; miR-146b-5p, miR-223, miR-150, miR-16, miR-191 and lncRNA NEAT1 in HIV/AIDS; miR-451 and miR-16 in malaria; miR-361-3p, miR-193b, miR-671, lncRNA 7SL in leishmaniasis; miR-101, miR-196b, miR-27b and miR-29c in leprosy. Furthermore, some ncRNAs have emerged as potential therapeutic targets, some of which include lncRNAs NEAT1, NEAT2 and lnr6RNA, 152742 in tuberculosis; MALAT1, HEAL, SAF, lincRNA-p21, NEAT1, GAS5, NRON, LINC00173 in HIV/AIDS; miRNA-146a in malaria. Finally, miR-135 and miR-126 were proposed as potential targets for the development of therapeutic vaccine against leishmaniasis. We also identify and discuss knowledge gaps that warrant for increased research work. These include investigation of the role of ncRNAs in the etiology of African trypanosomiasis and the assessment of the diagnostic potential of ncRNAs for malaria, and African trypanosomiasis. The potential targeting of ncRNAs for adjunctive therapy against tuberculosis, leishmaniasis, African trypanosomiasis and leprosy, as well as their targeting in vaccine development against tuberculosis, HIV/AIDS, malaria, African trypanosomiasis and leprosy are also new avenues to explore.

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

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

A novel integrated molecular and serological analysis method to predict new cases of leprosy amongst household contacts

Background

Early detection of Mycobacterium leprae is a key strategy for disrupting the transmission chain of leprosy and preventing the potential onset of physical disabilities. Clinical diagnosis is essential, but some of the presented symptoms may go unnoticed, even by specialists. In areas of greater endemicity, serological and molecular tests have been performed and analyzed separately for the follow-up of household contacts, who are at high risk of developing the disease. The accuracy of these tests is still debated, and it is necessary to make them more reliable, especially for the identification of cases of leprosy between contacts. We proposed an integrated analysis of molecular and serological methods using artificial intelligence by the random forest (RF) algorithm to better diagnose and predict new cases of leprosy.

Methods

The study was developed in Governador Valadares, Brazil, a hyperendemic region for leprosy. A longitudinal study was performed, including new cases diagnosed in 2011 and their respective household contacts, who were followed in 2011, 2012, and 2016. All contacts were diligently evaluated by clinicians from Reference Center for Endemic Diseases (CREDEN-PES) before being classified as asymptomatic. Samples of slit skin smears (SSS) from the earlobe of the patients and household contacts were collected for quantitative polymerase chain reaction (qPCR) of 16S rRNA, and peripheral blood samples were collected for ELISA assays to detect LID-1 and ND-O-LID.

Results

The statistical analysis of the tests revealed sensitivity for anti-LID-1 (63.2%), anti-ND-O-LID (57.9%), qPCR SSS (36.8%), and smear microscopy (30.2%). However, the use of RF allowed for an expressive increase in sensitivity in the diagnosis of multibacillary leprosy (90.5%) and especially paucibacillary leprosy (70.6%). It is important to report that the specificity was 92.5%.

Conclusion

The proposed model using RF allows for the diagnosis of leprosy with high sensitivity and specificity and the early identification of new cases among household contacts.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae) that can infect cells in the skin and nerves. Despite efforts to eliminate leprosy, the number of M. leprae infected individuals who develop leprosy is still substantial in the world. The diagnosis relies mainly on clinical parameters. Histopathological and bacteriological analysis help to classify clinical forms of patients. Serology and polymerase chain reaction (PCR) assays are claimed by health professionals as auxiliary tools, but until now these tests have been used almost exclusively in research, with minor use in leprosy reference centers throughout Brazil. Here, we tested quantitative PCR (qPCR) designed to amplify specific M. leprae targets and ELISA assays to detect antibody response to recombinant antigens (LID-1, ND-O-LID). All results were analyzed by multivariate analysis based in artificial intelligence. We chose random forest as a classification algorithm to aid in the diagnosis and the monitoring of contacts. The results allowed us to diagnose cases of leprosy with high sensitivity and specificity and the early identification of new cases among household contacts.

Leprosy: A great imitator

In recent years, advances in medical diagnosis and treatment have greatly attracted our attention, whereas some rare diseases, such as leprosy, have not found a place in the medical education curriculum; their existence may even be forgotten. Although the prevalence and incidence rates for leprosy have been significantly reduced as a result of the control strategies of the World Health Organization, new cases still appear. A total of 214,783 new cases were reported from 143 countries during 2016, corresponding to the global new-case detection rate of 2.9 per 100,000 population. Leprosy proves to be a very interesting model due to its immunologic properties. It joins with syphilis, mycosis fungoides, cutaneous tuberculosis, and sarcoidosis as one of the great imitators. The diagnosis of leprosy can be simple and practical, but considering the diagnosis of leprosy in the differential diagnosis is the first requisite again.

Autoimmunity to Tropomyosin-Specific Peptides Induced by Mycobacterium leprae in Leprosy Patients: Identification of Mimicking Proteins

Background

It has been shown earlier that there is a rise in the levels of autoantibodies and T cell response to cytoskeletal proteins in leprosy. Our group recently demonstrated a rise in both T and B cell responses to keratin and myelin basic protein in all types of leprosy patients and their associations in type 1 reaction (T1R) group of leprosy.

Objectives

In this study, we investigated the association of levels of autoantibodies and lymphoproliferation against myosin in leprosy patients across the spectrum and tried to find out the mimicking proteins or epitopes between host protein and protein/s of Mycobacterium leprae.

Methodology

One hundred and sixty-nine leprosy patients and 55 healthy controls (HC) were enrolled in the present study. Levels of anti-myosin antibodies and T-cell responses against myosin were measured by ELISA and lymphoproliferation assay, respectively. Using 2-D gel electrophoresis, western blot and MALDI-TOF/TOF antibody-reactive spots were identified. Three-dimensional structure of mimicking proteins was modeled by online server. B cell epitopes of the proteins were predicted by BCPREDS server 1.0 followed by identification of mimicking epitopes. Mice of inbred BALB/c strain were hyperimmunized with M. leprae soluble antigen (MLSA) and splenocytes and lymph node cells of these animals were adoptively transferred to naïve mice.

Results

Highest level of anti-myosin antibodies was noted in sera of T1R leprosy patients. We observed significantly higher levels of lymphoproliferative response (p < 0.05) with myosin in all types of leprosy patients compared to HC. Further, hyperimmunization of inbred BALB/c strain of female mice and rabbit with MLSA revealed that both hyperimmunized rabbit and mice evoked heightened levels of antibodies against myosin and this autoimmune response could be adoptively transferred from hyperimmunized to naïve mice. Tropomyosin was found to be mimicking with ATP-dependent Clp protease ATP-binding subunit of M. leprae. We found four mimicking epitopes between these sequences.

Conclusion

These data suggest that these mimicking proteins tropomyosin and ATP-dependent Clp protease ATP-binding subunit of M. leprae or more precisely mimicking epitopes (four B cell epitopes) might be responsible for extensive tissue damage during type1 reaction in leprosy.

Community knowledge, perceptions and attitudes regarding leprosy in rural Cameroon: The case of Ekondotiti and Mbonge health districts in the South-west Region

BACKGROUND

Although leprosy is one of the oldest diseases known to humanity, it remains largely misunderstood. Misconceptions about leprosy lead to stigma towards people with the disease. This study aimed at exploring the knowledge, perceptions and attitudes regarding leprosy in rural Cameroon.

METHODS

We carried out a cross-sectional community survey of 233 respondents aged 15-75 years, free from leprosy, and living in two rural health districts of the South-west Region of Cameroon. A questionnaire designed to evaluate knowledge, perceptions and attitudes about leprosy was used. Binary logistic regression was used to determine independent predictors of negative attitudes.

RESULTS

About 82% of respondents had heard about, and 64.4% knew someone with leprosy. Information on leprosy was mainly from community volunteers (40.6%), friends (38.0%), and the media (24%). Only 19.7% of respondents knew the cause of leprosy, and a considerable proportion linked it to a spell (25.3%), unclean blood (15.5%) and heredity (14.6%). About 72% knew that leprosy is curable and 86.3% would advise medical treatment. Attitudes towards leprosy patients were generally negative. Only 42% would shake hands, 32.6% would share the same plate, and 28.3% and 27% respectively, would allow their child to play or marry a person with leprosy. Furthermore, only 33.9% approved of participation of leprosy patients, and 42.9% of their employment. Independent predictors of negative attitudes were: the belief that leprosy is a curse; is caused by a germ; and having seen a leprosy patient. The negative attitudes were dampened by: the beliefs that leprosy is a punishment, is hereditary and is due to poor personal hygiene.

CONCLUSION

An awareness intervention using community volunteers and the media, with information on the cause of leprosy, its clinical manifestations and curability, and sensitization messages correcting the misconceptions and beliefs regarding leprosy, could improve the community knowledge and attitudes towards leprosy. This would ultimately contribute to the reduction of leprosy burden in the community.

The Physicochemical Basis of Clofazimine-Induced Skin Pigmentation

Clofazimine is a weakly basic, Food and Drug Administration-approved antibiotic recommended by the World Health Organization to treat leprosy and multi-drug-resistant tuberculosis. Upon prolonged treatment, clofazimine extensively bioaccumulates and precipitates throughout the organism, forming crystal-like drug inclusions (CLDIs). Due to the drug's red color, it is widely believed that clofazimine bioaccumulation results in skin pigmentation, its most common side effect. To test whether clofazimine-induced skin pigmentation is due to CLDI formation, we synthesized a closely related clofazimine analog that does not precipitate under physiological pH and chloride conditions that are required for CLDI formation. Despite the absence of detectable CLDIs in mice, administration of this analog still led to significant skin pigmentation. In clofazimine-treated mice, skin cryosections revealed no evidence of CLDIs when analyzed with a microscopic imaging system specifically designed for detecting clofazimine aggregates. Rather, the reflectance spectra of the skin revealed a signal corresponding to the soluble, free base form of the drug. Consistent with the low concentrations of clofazimine in the skin, these results suggest that clofazimine-induced skin pigmentation is not due to clofazimine precipitation and CLDI formation, but rather to the partitioning of the circulating, free base form of the drug into subcutaneous fat.

Differential Expression of MicroRNAs in Leprosy Skin Lesions

Leprosy, a chronic infectious disease caused by Mycobacterium leprae, is a major public health problem in poor and developing countries of the Americas, Africa, and Asia. MicroRNAs (miRNAs), which are small non-coding RNAs (18–24 nucleotides), play an important role in regulating cell and tissue homeostasis through translational downregulation of messenger RNAs (mRNAs). Deregulation of miRNA expression is important for the pathogenesis of various neoplastic and non-neoplastic diseases and has been the focus of many publications; however, studies on the expression of miRNAs in leprosy are rare. Herein, an extensive evaluation of differentially expressed miRNAs was performed on leprosy skin lesions using microarrays. Leprosy patients, classified according to Ridley and Jopling’s classification or reactional states (R1 and R2), and healthy controls (HCs) were included. Punch biopsies were collected from the borders of leprosy lesions (10 tuberculoid, 10 borderline tuberculoid, 10 borderline borderline, 10 borderline lepromatous, 4 lepromatous, 14 R1, and 9 R2) and from 9 HCs. miRNA expression profiles were obtained using the Agilent Microarray platform with miRBase, which consists of 1,368 Homo sapiens (hsa)-miRNA candidates. TaqMan quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) was used to validate differentially expressed miRNAs. Sixty-four differentially expressed miRNAs, including 50 upregulated and 14 downregulated (fold change ≥2.0, p-value ≤ 0.05) were identified after comparing samples from patients to those of controls. Twenty differentially expressed miRNAs were identified exclusively in the reactional samples (14 type 1 and 6 type 2). Eight miRNAs were validated by RT-PCR, including seven upregulated (hsa-miR-142-3p, hsa-miR-142-5p, hsa-miR-146b-5p, hsa-miR-342-3p, hsa-miR-361-3p, hsa-miR-3653, and hsa-miR-484) and one downregulated (hsa-miR-1290). These miRNAs were differentially expressed in leprosy and several other diseases, especially those related to the immune response. Moreover, the integration of analysis of validated mi/mRNAs obtained from the same samples allowed target pairs opposite expression pattern of hsa-miRNA-142-3p and AKR1B10, hsa-miRNA-342-3p and FAM180b, and hsa-miRNA-484 and FASN. This study identified several miRNAs that might play an important role in the molecular pathogenesis of the disease. Moreover, these deregulated miRNAs and their respective signaling pathways might be useful as therapeutic markers, therapeutic targets, which could help in the development of drugs to treat leprosy.

Evaluation of polymerase chain reaction in nerve biopsy specimens of patients with Hansen's disease

BACKGROUND

Pure neuritic variety of leprosy (PNL) presents as peripheral neuropathy with absent skin lesions and negative skin smears. Diagnosing PNL is an uphill task as most of these patients have nonspecific changes on nerve biopsy. In such circumstances, additional molecular diagnostic tools like polymerase chain reaction (PCR) has proven to be useful in diagnosing leprosy. The present study was planned to evaluate the role of PCR in nerve biopsy specimens of patients with PNL.

METHODS

Patients attending the neuromuscular clinic from January 2013 to June 2014 with mononeuropathy multiplex underwent detailed diagnostic evaluation to ascertain the cause of neuropathy. Patients where this evaluation failed to establish an etiology underwent a nerve biopsy.

RESULTS

Nerve biopsy was done in 52 patients, of which 35 were diagnosed as pure neuritic leprosy. Definite leprosy with positive wade fite staining for lepra bacilli was seen in 13 patients and 22 biopsies revealed a probable leprosy without lepra bacilli being identified. PCR for M. leprae was positive in 22 patients (62%). 12 of the 13 cases with definite leprosy on histopathology were PCR positive while in the AFB negative group, PCR was positive in 10 cases. PCR had a sensitivity of 92.3%, specificity of 54.5%. The positive and negative predictive value of PCR was 54.5% and 92.3% respectively.

CONCLUSIONS

PCR helps in diagnosing PNL in doubtful cases. A positive PCR increases the sensitivity of detection of M. leprae especially in cases of probable PNL group where AFB cannot be demonstrated on histopathology.

The formation of lipid droplets favors intracellular Mycobacterium leprae survival in SW-10, non-myelinating Schwann cells

Leprosy is a chronic infectious disease that is caused by the obligate intracellular pathogen Mycobacterium leprae (M.leprae), which is the leading cause of all non-traumatic peripheral neuropathies worldwide. Although both myelinating and non-myelinating Schwann cells are infected by M.leprae in patients with lepromatous leprosy, M.leprae preferentially invades the non-myelinating Schwann cells. However, the effect of M.leprae infection on non-myelinating Schwann cells has not been elucidated. Lipid droplets (LDs) are found in M.leprae-infected Schwann cells in the nerve biopsies of lepromatous leprosy patients. M.leprae-induced LD formation favors intracellular M.leprae survival in primary Schwann cells and in a myelinating Schwann cell line referred to as ST88-14. In the current study, we initially characterized SW-10 cells and investigated the effects of LDs on M.leprae-infected SW-10 cells, which are non-myelinating Schwann cells. SW-10 cells express S100, a marker for cells from the neural crest, and NGFR p75, a marker for immature or non-myelinating Schwann cells. SW-10 cells, however, do not express myelin basic protein (MBP), a marker for myelinating Schwann cells, and myelin protein zero (MPZ), a marker for precursor, immature, or myelinating Schwann cells, all of which suggests that SW-10 cells are non-myelinating Schwann cells. In addition, SW-10 cells have phagocytic activity and can be infected with M. leprae. Infection with M. leprae induces the formation of LDs. Furthermore, inhibiting the formation of M. leprae-induced LD enhances the maturation of phagosomes containing live M.leprae and decreases the ATP content in the M. leprae found in SW-10 cells. These facts suggest that LD formation by M. leprae favors intracellular M. leprae survival in SW-10 cells, which leads to the logical conclusion that M.leprae-infected SW-10 cells can be a new model for investigating the interaction of M.leprae with non-myelinating Schwann cells.

Leprosy is a chronic infectious disease that is caused by the obligate intracellular pathogen Mycobacterium leprae (M.leprae). Leprosy is the leading cause of all non-traumatic peripheral neuropathies worldwide. Both myelinating and non-myelinating Schwann cells are infected by M.leprae in lepromatous leprosy, but the non-myelinating Schwann cells show greater susceptibility to M.leprae invasion. However, the effect of M.leprae infection on non-myelinating Schwann cells has not been elucidated. Our results show that SW-10 cells are non-myelinating Schwann cells. Infection with M. leprae induces lipid droplet (LD) formation. Furthermore, inhibition of M. leprae-induced LD formation enhances the maturation of phagosomes containing live M.leprae and decreases the ATP content of M. leprae in SW-10 cells, suggesting that LD formation by M. leprae favors M. leprae survival in SW-10 cells. Based on these findings, it should be clear that M.leprae-infected SW-10 cells can serve as a new model for investigating the interaction of M.leprae with non-myelinating Schwann cells.

Analysis of clinical data and T helper 1/T helper 2 responses in patients with different clinical forms of leprosy

INTRODUCTION:

Currently, there are no laboratory tests or sensitive and specific molecular markers for the early diagnosis of leprosy. The aim of this study was to analyze the clinical characteristics of patients with leprosy and investigate their immunological profile, comparing this with the type of lesion and the presence or absence of a Bacillus Calmette-Guérin (BCG) vaccination scar.

METHODS:

Statistical analyzes were performed by employing comparative tests (Pearson´s chi-square) to evaluate the variables in different clinical forms, considering significance at the 5% level.

RESULTS:

The study identified a predominance of lepromatous leprosy (26.9%) in patients aged between 34-53 years. Caucasians predominantly had borderline tuberculoid (BT) clinical forms (42%); a predominance of males with borderline lepromatous (19%) and lepromatous leprosy (26.9%) forms was observed; and the presence of BCG vaccination scars (27.5%) and lower limb nerves were more affected (38%) predominantly in the BT clinical form. Significant differences were identified, which included hypochromic lesions predominantly in the BT clinical form (24%); diffuse-type lesions predominantly in the tuberculoid (TT) clinical form (28%); ill-defined lesion border dominance in lepromatous leprosy (LL) clinical forms (30%); an irregular lesion limit predominantly in LL clinical forms (32%); and a predominant Th1 immune response in the BT clinical form (41.7%).

CONCLUSIONS:

The evaluation of the immunological profile in leprosy patients may contribute to the more detailed diagnosis and possibly better characterization of the prognosis for these individuals.

Leprosy and women

Leprosy has an impact on the physical, social, and psychological health of affected people. Women in developing countries seek health care late for any health-related issues. Leprosy, a disease known for its stigma, adds further to these facts. Also, close contact between women and family members, especially children, increases the chance of transmission to others and thereby increases the disease burden in the society. Hence, leprosy in women is an important issue for the affected patient, their family members, and society as a whole.

The Burden of Leprosy in Cameroon: Fifteen Years into the Post-elimination Era

BACKGROUND

Cameroon achieved the elimination target of leprosy in 2000, and has maintained this status ever since. However, a number of health districts in the country continue to report significant numbers of leprosy cases. The aim of this study was to assess the burden of leprosy in Cameroon from 2000 to 2014.

METHODS

We obtained and analysed using the new leprosy burden concept of analysis, leprosy surveillance data collected between 2000 and 2014 from the National Leprosy Control Programme.

PRINCIPAL FINDINGS

Cameroon achieved leprosy elimination in 2000, registering a prevalence rate of 0.94/10,000 population. The prevalence rate dropped further to reach 0.20/10,000 population (78% reduction) in 2014. Similarly, the new case detection rate dropped from 4.88/100,000 population in 2000 to 1.46/100,000 population (85.3% reduction) in 2014. All 10 regions of the country achieved leprosy elimination between 2000 and 2014; however, 10 health districts were still to do so by 2014. The number of high-leprosy-burden regions decreased from 8 in 2000 to 1 in 2014. Seven and two regions were respectively medium and low-burdened at the end of 2014. At the health districts level, 18 remained at the high-leprosy-burdened level in 2014.

CONCLUSION

The leprosy prevalence and detection rates as well as the overall leprosy burden in Cameroon have dropped significantly between 2000 and 2014. However, a good number of health districts remain high-leprosy-burdened. The National Leprosy Control Programme should focus efforts on these health districts in the next coming years in order to further reduce the burden of leprosy in the country.

Genome-Wide Screening of mRNA Expression in Leprosy Patients

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

Adverse effects of alternative therapy (minocycline, ofloxacin, and clofazimine) in multibacillary leprosy patients in a recognized health care unit in Manaus, Amazonas, Brazil

BACKGROUND:

After the introduction of the multidrug therapy, there was a decline in the coefficients of prevalence and detection of new cases of leprosy. However, the records of drug resistance and relapses are threatening factors in leprosy control. Hence, new alternative schemes and monitoring of adverse effects to avoid treatment abandonment are important considerations.

OBJECTIVE:

Describe the side effects of a multidrug regimen containing minocycline, ofloxacin, and clofazimine in multibacillary leprosy patients.

METHODS:

We conducted a prospective, descriptive, and observational study with multibacillary patients, including cases of intolerance to standard MDT and relapses. The study was carried out at Fundação Alfredo da Matta (Alfredo da Matta Foundation), in Manaus, Amazonas, from April 2010 to January 2012. The patients received alternative therapy, which consisted of daily self-administered doses of 100mg of minocycline, 400 mg of ofloxacin, and 50mg of clofazimine and a supervised monthly dose of 300mg of clofazimine for six months, followed by eighteen months of daily doses of ofloxacin 400mg, clofazimine 50mg, and a supervised monthly dose of clofazimine 300mg. Results: Twenty-one cases were included. Mild and transitory side effects occurred in 33.3% of patients. Of the total episodes, 45.9% were attributed to ofloxacin and they included abdominal pain, nausea, vomiting, headache, and insomnia; 21.6% were due to clofazimine, with 100% of patients presenting skin pigmentation. The mean time for the development of adverse effects after beginning the therapy was 15.2 days.

CONCLUSION:

All patients tolerated the drugs well, and compliance was satisfactory, with no serious events. Unlike other standard MDT studies had shown, no treatment was stopped due to side effects. Nevertheless, patient follow-up and studies with bigger samples are necessary to guarantee the efficacy and safety of the alternative regimen as a second-line scheme in multi-drug therapy.

Unveiling healthy carriers and subclinical infections among household contacts of leprosy patients who play potential roles in the disease chain of transmission

Leprosy transmission still occurs despite the availability of highly effective treatment. The next step towards successfully eliminating leprosy is interrupting the chain of transmission of the aetiological agent, Mycobacterium leprae. In this investigation, we provide evidence that household contacts (HHCs) of leprosy patients might not only have subclinical infections, but may also be actively involved in bacilli transmission. We studied 444 patients and 1,352 contacts using anti-phenolic glycolipid-I (PGL-I) serology and quantitative polymerase chain reaction (qPCR) to test for M. leprae DNA in nasal swabs. We classified the patients according to the clinical form of their disease and the contacts according to the characteristics of their index case. Overall, 63.3% and 34.2% of patients tested positive by ELISA and PCR, respectively. For HHCs, 13.3% had a positive ELISA test result and 4.7% had a positive PCR test result. The presence of circulating anti-PGL-I among healthy contacts (with or without a positive PCR test result from nasal swabs) was considered to indicate a subclinical infection. DNA detected in nasal swabs also indicates the presence of bacilli at the site of transmission and bacterial entrance. We suggest that the concomitant use of both assays may allow us to detect subclinical infection in HHCs and to identify possible bacilli carriers who may transmit and disseminate disease in endemic regions. Chemoprophylaxis of these contacts is suggested.

Identification of mimotopes of Mycobacterium leprae as potential diagnostic reagents

BACKGROUND

An early diagnostic test for detecting infection in leprosy is fundamental for reducing patients' sequelae. The currently used lepromin is not adequate for disease diagnosis and, so far, no antigen to be used in intradermoreaction has proved to be sensitive and specific for that purpose. Aiming at identifying new reagents to be used in skin tests, candidate antigens were investigated.

METHODS

Random peptide phage display libraries were screened by using antibodies from leprosy patients in order to identify peptides as diagnostic reagents.

RESULTS

Seven different phage clones were identified using purified antibodies pooled from sera of leprosy patients. When the clones were tested with serum samples by ELISA, three of them, 5A, 6A and 1B, allowed detecting a larger number of leprosy patients when compared to controls. The corresponding peptides expressed by selected phage clones were chemically synthesized. A pilot study was undertaken to assess the use of peptides in skin tests. The intradermal challenge with peptides in animals previously sensitized with Mycobacterium leprae induced a delayed-type hypersensitivity with peptide 5A (2/5) and peptide 1B (1/5). In positive controls, there was a 3/5 reactivity for lepromin and a 4/5 reactivity of the sensitized animals with soluble extract of M. leprae.

CONCLUSIONS

The preliminary data suggest that may be possible to develop reagents with diagnostic potential based on peptide mimotopes selected by phage display using polyclonal human antibodies.

Limited susceptibility of cynomolgus monkeys (Macaca fascicularis) to leprosy after experimental administration of Mycobacterium leprae

Cynomolgus monkeys are a useful model for human tuberculosis, but susceptibility to M. leprae is unknown. A cynomolgus model of leprosy could increase understanding of pathogenesis-importantly, neuritis and nerve-damaging reactions. We administered viable Mycobacterium leprae to 24 cynomolgus monkeys by three routes, with a median follow-up period of 6 years (range = 1-19 years) involving biopsies, nasal smears, antiphenolic glycolipid-1 (PGL-1) antibody serology, and lepromin skin testing. Most developed evanescent papules at intradermal M. leprae inoculation sites that, on biopsy, showed a robust cellular immune response akin to a lepromin skin test reaction; many produced PGL-1 antibodies. At necropsy, four monkeys, without cutaneous or gross neurological signs of leprosy but with elevated PGL-1 antibodies, including three with nasal smears (+) for acid fast bacilli (AFB), showed histological features, including AFB, suggestive of leprosy at several sites. Overall, however, cynomolgus monkeys seem minimally susceptible to leprosy after experimental M. leprae administration.

Leprosy: an overview of pathophysiology

Leprosy, also known as Hansen's disease, is a chronic infectious disease caused by Mycobacterium leprae, a microorganism that has a predilection for the skin and nerves. The disease is clinically characterized by one or more of the three cardinal signs: hypopigmented or erythematous skin patches with definite loss of sensation, thickened peripheral nerves, and acid-fast bacilli detected on skin smears or biopsy material. M. leprae primarily infects Schwann cells in the peripheral nerves leading to nerve damage and the development of disabilities. Despite reduced prevalence of M. leprae infection in the endemic countries following implementation of multidrug therapy (MDT) program by WHO to treat leprosy, new case detection rates are still high-indicating active transmission. The susceptibility to the mycobacteria and the clinical course of the disease are attributed to the host immune response, which heralds the review of immunopathology of this complex disease.

Effect of corticosteroid usage combined with multidrug therapy on nerve damage assessed using nerve conduction studies: a prospective cohort study of 365 untreated multibacillary leprosy patients

The purpose of this study is to determine the extent of nerve involvement and to study the effect of corticosteroids combined with multidrug therapy on nerve damage in leprosy patients using sensory and motor nerve conduction studies. A cohort of 365 untreated multibacillary leprosy patients were prospectively studied using sensory and motor nerve conduction studies on upper and lower limb nerves. They were subgrouped as those to be treated with 12-week regimen of corticosteroids for reaction and/or neuritis or silent neuropathy of <6 months duration along with 12-month multidrug therapy (group A), and those with no reaction were treated with multidrug therapy only (group B). Analysis was performed using SPSS version 10.0. Significance of association was tested using chi(2) test. At registration, abnormality by nerve conduction studies was seen in 92% of patients and majority (65%) showing involvement of more than five sensory and motor nerves. Sensory nerve abnormalities were higher (52%) than motor (37%) (P < 0.001). Affection of sensory and motor nerves was higher in group A (P < 0.001). Notably, 40% nerves in group B also showed impairment at 0 month. This implies that almost all patients showed abnormal nerve conduction studies at onset regardless of reaction, proving nerve damage is more widespread than envisaged. At 18 months, overall percentile deterioration (23%) of nerves was higher than improvement (9%) (P < 0.001) indicating that corticosteroids combined with multidrug therapy failed to significantly improve the nerve status. Sensory nerve (57%) affection was significantly higher than motor (46%) (P < 0.001). Moreover, percentile deterioration of sensory nerves was higher in group A (P < 0.001) implying corticosteroids is not very efficacious in the prevention or reversal of nerve damage. Electrophysiological tests provide valuable information for detecting nerve function impairment and evaluating appropriate therapeutic regimens.

Interventions for erythema nodosum leprosum

BACKGROUND

Erythema nodosum leprosum (ENL) is a serious immunological complication of leprosy, causing inflammation of skin, nerves, other organs, and general malaise. Many different therapies exist for ENL, but it is unclear if they work or which therapy is optimal.

OBJECTIVES

To assess the effects of interventions for erythema nodosum leprosum.

SEARCH STRATEGY

We searched the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 1, 2009), MEDLINE (from 2003), EMBASE (from 2005), LILACS and AMED (from inception), CINAHL (from 1981), and databases of ongoing trials, all in March 2009. We checked reference lists of articles and contacted the American Leprosy Missions in Brazil to locate studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of interventions for ENL in people with leprosy.

DATA COLLECTION AND ANALYSIS

Two authors performed study selection, assessed trial quality, and extracted data.

MAIN RESULTS

We included 13 studies with a total of 445 participants. The quality of the trials was generally poor and no results could be pooled due to the treatments being so heterogeneous. Treatment with thalidomide showed a significant remission of skin lesions compared to acetylsalicylic acid (aspirin) (RR 2.43; 95% CI 1.28 to 4.59) (1 trial, 92 participants). Clofazimine treatment was superior to prednisolone (more treatment successes; RR 3.67; 95% CI 1.36 to 9.91) (1 trial, 24 participants), and thalidomide (fewer recurrences; RR 0.08; 95% CI 0.01 to 0.56) (1 trial, 72 participants). We did not find any significant benefit for intravenous betamethasone compared to dextrose (1 trial, 10 participants), pentoxifylline compared to thalidomide (1 trial, 44 participants), indomethacin compared to prednisolone, aspirin or chloroquine treatments (2 trials, 80 participants), or levamisole compared to placebo (1 trial, 12 participants). Mild to moderate adverse events were significantly lower in participants taking 100 mg thalidomide compared to 300 mg thalidomide daily (RR 0.46; 95% CI 0.23 to 0.93). Significantly more minor adverse events were reported in participants taking clofazimine compared with prednisolone (RR 1.92; 95% CI 1.10 to 3.35). None of the studies assessed quality of life or economic outcomes.

AUTHORS' CONCLUSIONS

There is some evidence of benefit for thalidomide and clofazimine, but generally we did not find clear evidence of benefit for interventions in the management of ENL. However, this does not mean they do not work, because the studies were small and poorly reported. Larger studies using clearly defined participants, outcome measures, and internationally recognised scales are urgently required.

Sporulation in mycobacteria

Mycobacteria owe their success as pathogens to their ability to persist for long periods within host cells in asymptomatic, latent forms before they opportunistically switch to the virulent state. The molecular mechanisms underlying the transition into dormancy and emergence from it are not clear. Here we show that old cultures of Mycobacterium marinum contained spores that, upon exposure to fresh medium, germinated into vegetative cells and reappeared again in stationary phase via endospore formation. They showed many of the usual characteristics of well-known endospores. Homologues of well-known sporulation genes of Bacillus subtilis and Streptomyces coelicolor were detected in mycobacteria genomes, some of which were verified to be transcribed during appropriate life-cycle stages. We also provide data indicating that it is likely that old Mycobacterium bovis bacillus Calmette-Guérin cultures form spores. Together, our data show sporulation as a lifestyle adapted by mycobacteria under stress and tempt us to suggest this as a possible mechanism for dormancy and/or persistent infection. If so, this might lead to new prophylactic strategies.

[Detection of Mycobacterium leprae DNA in nasal swab]

Studies have demonstrated high sensibility of the polimerase chain reaction (PCR) technique in the identification of the Mycobacterium leprae DNA . This study aimed to evalue the PCR sensibility at the detection of the M. leprae DNA in nasal swab of leprosy patients and to compare the results with the bacilloscopy and multibacillary (MBs) and paucibacilares (PBs) forms. Nasal secretion samples of 24 leprosy patients were collected, and were preserved in one and two lise's solution. The PCR results were highly significant (p <0.0000) and they revealed grater sensibility than bacilloscopy, in several clinical forms. Nevertheless, still different studies are necessary, testing new markers and preservatives, with the purpose of lifting up the sensibility of this technique, in nasal secretion samples.

Synthetic EthR inhibitors boost antituberculous activity of ethionamide

The side effects associated with tuberculosis therapy bring with them the risk of noncompliance and subsequent drug resistance. Increasing the therapeutic index of antituberculosis drugs should thus improve treatment effectiveness. Several antituberculosis compounds require in situ metabolic activation to become inhibitory. Various thiocarbamide-containing drugs, including ethionamide, are activated by the mycobacterial monooxygenase EthA, the production of which is controlled by the transcriptional repressor EthR. Here we identify drug-like inhibitors of EthR that boost the bioactivation of ethionamide. Compounds designed and screened for their capacity to inhibit EthR-DNA interaction were co-crystallized with EthR. We exploited the three-dimensional structures of the complexes for the synthesis of improved analogs that boosted the ethionamide potency in culture more than tenfold. In Mycobacterium tuberculosis-infected mice, one of these analogs, BDM31343, enabled a substantially reduced dose of ethionamide to lessen the mycobacterial load as efficiently as the conventional higher-dose treatment. This provides proof of concept that inhibiting EthR improves the therapeutic index of thiocarbamide derivatives, which should prompt reconsideration of their use as first-line drugs.

Serum Proteome of Leprosy Patients Undergoing Erythema Nodosum Leprosum Reaction: Regulation of Expression of the Isoforms of Haptoglobin

Validated proteome profile allows better understanding of disease progression, subtype classification, susceptibility patterns, and disease prognosis. Leprosy is a spectral disease, with clinically, histologically, immunologically, and bacteriologically distinguishable subtypes. In addition, a significant fraction of patients undergo immune mediated reactions even after multidrug therapy (MDT). Erythema nodosum leprosum (ENL) is an immune complex mediated reactional condition in leprosy, characterized by a systemic inflammatory condition afflicting borderline lepromatous (BL) and lepromatous leprosy patients (LL). In this study, we have analyzed serum proteome of leprosy patients undergoing ENL reactions and compared it with that of healthy noncontact controls. Depletion of albumin and immunoglobulin G (IgG) was optimized using Aurum serum protein mini kit (Bio-Rad), and then two-dimensional gel electrophoresis (2-DE) of these serum samples was performed. Differentially expressed proteins were identified by MALDI-TOF and MALDI-TOF MS/MS mass spectrometry. Significant increase in one of the isoforms of alpha2 chain of haptoglobin was observed in ENL condition. In addition, haptoglobin phenotype was determined for healthy controls and leprosy patients. Hp 0-0 phenotype was detected in 21.4% of the ENL patients undergoing treatment, which on follow up examination showed typable phenotype, thus showing a condition of acquired anhaptoglobinemia. Since ENL still remains a threat to leprosy disease management, the above findings may provide new insights in understanding the development and progression of this inflammatory condition.

Genomics of host-pathogen interactions

The complete sequences of hundreds of microbial genomes have provided drug discovery pipelines with thousands of new potential drug targets. Their availability has also stimulated the development of a variety of innovative approaches that allow functional studies to be performed on the entire genome of an organism. This chapter describes how these approaches have been applied to the analysis of host-pathogen interactions and discusses how such studies might facilitate the development of new antibiotics.

A simplified reverse transcriptase PCR for rapid detection ofMycobacterium lepraein skin specimens

An RNA-based assay is an additional molecular tool for leprosy diagnosis and determination of the viability of leprosy bacilli. To simplify RNA detection, a one-step reverse transcriptase PCR (RT-PCR) was established and evaluated. RNA and DNA could be isolated simultaneously. With the use of Mycobacterium leprae-specific primers targeting a 171-bp fragment of the M. leprae 16S RNA gene, RT-PCR resulted in detection of M. leprae in both slit skin smears and skin biopsy specimens. To enhance the positive signal, a digoxigenin-labeled DNA was developed, and successfully detected the amplified RT-PCR product. The method is sensitive, as it could detect one leprosy bacillus. When it was used directly on skin specimens collected from leprosy patients, 34 of 36 multibacillary (MB) and 13 of 24 paucibacillary (PB) cases showed positive results. The assay was also effective in monitoring bacterial clearance in leprosy patients during chemotherapy; after treatment with the multidrug therapy for 6 months, resulting in bacterial clearance, 16 of 36 MB patients and three of 24 PB patients tested were still positive for the 16S rRNA gene of M. leprae, suggesting the advisability of a more prolonged treatment course. This form of RT-PCR is of value in terms of simplicity and sensitivity in identifying M. leprae in routine skin specimens, especially when acid-fast bacilli are not discernable.

The genome of Mycobacterium leprae: a minimal mycobacterial gene set

Comparison of the recently sequenced genome of the leprosy-causing pathogen Mycobacterium leprae with other mycobacterial genomes reveals a drastic gene reduction and decay in M. leprae affecting many metabolic areas, exemplified by the retention of a minimal set of genes required for cell-wall biosynthesis.

Immunological relatedness of the protective mechanisms against tuberculosis and cancer

BACKGROUND

Bacille Calmette-Guérin (BCG), an attenuated strain of tuberculous bacillus, is the source of vaccines providing unclear and variable protection against tuberculosis (TB) and cancer. Thermostable macromolecular antigens (TMAs) are major mycobacterial complexes immunodominant in disease. A60 (TMA complex of BCG) protects mice against TB development, via T lymphocyte (TL)-mediated macrophage (Mphi) activation, halting intracellular mycobacterial replication. In most A60-primed mice, cytolytic TLs and Mphi infiltrate cancer tissue, resulting in 80-100% rejection. Adoptive TL transfer is indispensable for Mphi-dependent tumour cell inactivation via oxygen and nitrogen radicals. Neoplasm development induces immune anergy with depletion ofA60-specific TL and activated Mphi. A60 protects mice against TB and cancer by inducing the synthesis of three lymphokines: interleukin 2 (IL-2), interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha). Tumour cells prevent A60-dependent synthesis of these lymphokines in vivo and in vitro.

CONCLUSION

These data provide some clues to immune surveillance and tumour escape mechanisms, as well as to the antituberculous and antineoplastic BCG action.

Why intracellular parasitism need not be a degrading experience for Mycobacterium

The success of mycobacteria as pathogens hinges on their ability to infect and persist within the macrophages of their host. However, activation of host macrophages by cytokines from a productive cellular immune response can stimulate the cells to kill their resident pathogens. This suggests that the interaction between host cell and microbe is in delicate balance, which can be tipped in favour of either organism. Biochemical analysis of mycobacterial vacuoles has shown them to be integral to the host cell's recycling endosomal system. As such they show limited acidification and hydrolytic activity despite possession of known lysosomal constituents such as cathepsins D, B and L, and LAMP 1. Even in established infections, they remain dynamic compartments accessible to several plasmalemma-derived constituents. Once the macrophage has been activated by IFN-gamma and TNF-alpha the vacuoles coalesce and acidify. This marks a distinct alteration in vacuole physiology and leads to stasis and death of the mycobacteria. Mycobacteria have developed several strategies to avoid this outcome. Most notably, live bacilli-induce sustained release of IL-6 from infected macrophages. IL-6 blocks the ability of both polyclonal primary T cells and T-cell hybridomas to respond to appropriate stimuli. Such an activity could render the centres of infection foci, such as granulomas, anergic and thus avoid release of macrophage-activating cytokines. This paper discusses both the mechanisms by which mycobacteria try to ensure their success as intracellular pathogens and the relevance of these strategies to the overall understanding of mycobacterial diseases.

Arginine at positions 13 or 70-71 in pocket 4 of HLA-DRB1 alleles is associated with susceptibility to tuberculoid leprosy

Evaluation of human histocompatibility leukocyte antigen (HLA) class II genes in 54 cases of tuberculoid leprosy (TL) and 44 controls has shown a positive association with HLA-DRB1 alleles that contain Arg13 or Arg70-Arg71. Among TL patients, 87% carry specific alleles of DRB1 Arg13 or Arg70-Arg71 as compared to 43% among controls (p = 5 x 10(-6)) conferring a relative risk of 8.8. Thus, susceptibility to TL involves three critical amino acid positions of the beta chain, the side chains of which, when modeled on the DR1 crystal structure, line a pocket (pocket 4) accommodating the side chain of a bound peptide. This study suggests that disease susceptibility may be determined by the independent contribution of polymorphic residues participating in the formation of a functional arrangement (i.e., pocket) within the binding cleft of an HLA molecule.

Detection of Mycobacterium leprae infection by PCR

PCR amplification of the 531-bp fragment of the Mycobacterium leprae pra gene in fresh biopsy and slit skin smear samples was evaluated for its usefulness in the detection of leprosy bacilli in patients in Thailand. In multibacillary patients, 87.1% (27 of 31) of biopsy specimens and 41.9% (13 of 31) of slit skin smear specimens were positive by PCR, whereas in paucibacillary patients, 36.4% (8 of 22) of biopsy specimens and 18.2% (4 of 22) of slit skin smear specimens yielded detectable PCR amplification. Compared with other diagnostic procedures, PCR showed a clear advantage over both microscopic examination of slit skin smears and serologic detection of anti-phenolic glycolipid 1 antibody, especially in paucibacillary patients when bacterial indexes were 0 and seropositivity was only 6.25%. PCR was also evaluated for its potential to help monitor bacterial clearance in some of these patients during chemotherapeutic treatment. The PCR results on slit skin smear samples at 1, 3, and 6 months of chemotherapy showed that the number of PCR-positive cases of both multibacillary and paucibacillary types decreased sequentially. The results of this study are encouraging. However, investigation of a larger number of clinical specimens with an improvement in PCR methods, especially on slit skin smears, needs to be done before PCR can be established as a diagnostic procedure for leprosy patients and subclinical cases or as a tool for drug assessment.

Paratuberculosis

Paratuberculosis (Johne's disease) is a chronic, wasting, widespread mycobacteriosis of ruminants. It involves extensive mycobacterial shedding, which accounts for the high contagiousness, and ends with a fatal enteritis. Decreases in weight, milk production, and fertility produce severe economic loss. The DNA of the etiological agent (Mycobacterium paratuberculosis) has a base composition (66 to 67% G+C) within the range of that of mycobacteria (62 to 70% G+C), a size (4.4 x 10(6) to 4.7 x 10(6) bp) larger than that of most pathogenic mycobacteria (2.0 x 10(6) to 4.2 x 10(6) bp), and a high relatedness (> 90%) to Mycobacterium avium DNA. However, the DNAs of the two organisms can be distinguished by restriction fragment length polymorphism analysis. M. paratuberculosis genes coding for a transposase, a cell wall-associated protein (P34), and two heat shock proteins have been cloned and sequenced. Nucleic acid probes (two of which are species specific) are used, after PCR amplification, for M. paratuberculosis identification in stools and milk. As in leprosy, with disease progression, cellular immune reactions decrease and humoral immune reactions increase. Cutaneous testing with sensitins, lymphocyte proliferation assays, and cytokine tests are used to monitor cellular immune reactions in paratuberculosis, but these tests lack specificity. Complement fixation, immunodiffusion, and enzymometric tests based on antibodies to M. paratuberculosis extracts, to mycobacterial antigen complex A36, to glycolipids, and to proteins help identify affected cattle but are not species specific. The carboxyl-terminal portion of the 34-kDa cell wall-associated A36 protein (P34) carries species-specific B-cell epitopes and is the basis for an enzyme-linked immunosorbent assay. Diagnostic tests for paratuberculosis are also used in Crohn's disease, a chronic human ileitis mimicking Johne's disease, in which isolates identified as M. paratuberculosis have been found.

Progression from papilloma to carcinoma is accompanied by changes in antibody response to papillomavirus proteins

Cottontail rabbit papillomavirus induces benign tumors, papillomas, in rabbits which progress at a high frequency to malignant tumors, carcinomas. Cottontail rabbit papillomavirus therefore provides an experimental model for oncogenic human papillomaviruses. The nature of the antigens recognized by the host has not been identified at any stage of tumor development. Here, we characterized the humoral immune response to viral antigens in cottontail and domestic rabbits at the papilloma stage, in domestic rabbits at the carcinoma stage, and in animals in which papillomas had regressed. Antibodies to linear epitopes were identified by Western blotting (immunoblotting) with bacterial fusion proteins, and evidence for recognition of conformational epitopes was obtained by immunoprecipitation. An immune response to the early proteins E1, E2, E6, and E7 was detected only in a fraction of the animals, and all animals were negative for E4 and E5. The response to E6 and E7 peaked around 7 months and then decreased, while that to E1 and E2 remained level after an initial raise. The antibody response to structural proteins was low at the papilloma stage, and antibodies to L1 recognized predominantly conformational epitopes. As papillomas progressed to carcinomas, there was a drastic increase in the response to L1 and L2, suggesting a change in interaction between virus-infected host cells and the host's immune system.

Detection of Mycobacterium leprae and the potential for monitoring antileprosy drug therapy directly from skin biopsies by PCR

An improved protocol for PCR analysis of Mycobacterium leprae-infected tissues, based on enzymatic lysis, has been developed and used to demonstrate the feasibility of using PCR for detecting M. leprae in routine skin biopsies taken from leprosy patients throughout the clinical spectrum. Of 92 multibacillary patients tested, 99% were PCR-positive using gel electrophoresis or DNA hybridization to detect the amplified product. Similar analysis of paucibacillary patients, in which only one of 27 biopsies had demonstrable AFB microscopically, gave a positivity rate of 74%. No PCR signals were demonstrated from skin biopsies from seven patients with non-leprosy dermatoses and one AIDS patient with a disseminated atypical mycobacteriosis. Evaluation of leprosy patients with antileprosy drug therapy prior to biopsy demonstrated that PCR signals were either greatly diminished or absent after 2 months of continuous antibiotic therapy. PCR was also able to detect the presence of M. leprae in tissues of patients receiving antibacterial therapy when patients were suspected of harbouring drug-resistant M. leprae.

Pharmacoeconomics of antibacterial treatment

Antibacterial drugs account for between 3 and 25% of all prescriptions, between 6 and 21% of the total market value of drugs in a single country, and up to 50% of the drug budget in hospitals. Bacterial infection is widely perceived as disease caused by harmful outside agents which can be isolated and tested to select the best drug for treatment. In fact, the need for any treatment and the pros and cons of different drugs are just as debatable as in any other therapeutic area. Moreover, the bacteria which make up the normal flora of the body fulfil important roles, so that the ecological implications of treatment for the individual and for society should be considered in assessing the costs and consequences of antibacterial treatment. In this review we outline the most important issues relating to the treatment of bacterial infection in the community and in the hospital, contrasting information from developed and developing countries where appropriate. We review the existing literature on economic evaluation, but in general most of the literature deals with containing the costs of antibacterial drugs in hospitals, and there are many gaps in the literature on cost-effectiveness of treatment. Consequently there are still extreme variations in medical practice which present a challenge for future evaluation. As the outcomes of antibacterial treatment are apparent in a few weeks or months, this is an ideal field for testing pharmacoeconomic methodology. The desire to overcome medical practice variation through consensus statements should be avoided. Instead we recommend wider application of decision analysis to acknowledge that choices exist for the diagnosis and treatment of bacterial infection and to gather information about the implications of these choices. Much of the existing literature would be improved by a more explicit definition of costs. Direct costs to the health services should be distinguished from non medical costs. Moreover, the analysis should consider whether savings from one budget result in costs to another health service budget, or to the patient (transfer costs). These deficiencies in cost analysis will be relatively easy to correct. Of more concern is the fact that the efficacy of much antibacterial treatment is either totally debatable, or variable, depending on factors such as the type of patient treated or the quality of delivery of treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Specificity of IgG subclass antibodies in different clinical manifestations of leprosy

We analysed specific IgG subclasses levels to Mycobacterium leprae sonicate extract (MSE), lipoarabinomannan B (LAM) and phenolic glycolipid I (PGL-I) in the sera of leprosy patients with different clinical manifestations. IgG2 was found to be the predominant antibody to MSE regardless of clinical manifestations, and IgG1 response was mostly seen in lepromatous patients. IgG3 reacted only rarely but IgG4 reacted relatively more in certain clinical groups such as borderline lepromatous and lepromatous with erythema nodosum leprosum (ENL) reaction. Most of the IgG subclass responses to MSE could be accounted for reactivity with LAM, suggesting that LAM is the major immunogen involved in the pathogenesis of leprosy. In contrast to LAM, PGL-I antigen showed considerably lower reactivities for IgG subclasses. An association between IgG subclass responses and clinical manifestations of leprosy was also seen. Whereas borderline lepromatous patients were found to have significantly higher levels of IgG2 and IgG4 to MSE, lepromatous patients had elevated levels of IgG1 and lower levels of IgG2. An interesting observation, however, was the significantly higher levels of IgG2 to LAM in the pure neuritic leprosy patients.