Interleukin-17F single-nucleotide polymorphism (7488T>C) and its association with susceptibility to leprosy.

The objective of this study was to investigate the association, if any, between the interleukin-17F (7488T>C) (rs763780) polymorphism and susceptibility to leprosy and to elucidate the relationship between IL-17F genotypes and clinical profile of the disease. DNA was extracted from the peripheral venous blood of leprosy cases (n = 140), which were classified as per WHO classification into paucibacillary (PB) (n = 53) and multibacillary (MB) (n = 87) categories and healthy controls (n = 84) without any signs and symptoms of leprosy. The IL-17F (7488 T/C) polymorphism was genotyped using amplification refractory mutation system - polymerase chain reaction (Allele-specific amplification). In both PB and MB categories of leprosy cases, the homozygous TT genotype frequency was significantly higher than that of the healthy controls (78.70% vs. 29.76%, P < 0.05). The heterozygous TC genotype was higher in the controls than in the leprosy cases (57.14% vs. 17.68%, P < 0.05). TT genotype was more associated with the type 1 reactional states and tuberculoid/borderline tuberculoid groups in leprosy than the TC genotype. This study reveals that the IL-17F (7488T>C) single-nucleotide polymorphism is associated with susceptibility to leprosy and polymorphism confers decrease in risk of contracting leprosy in the north Indian cohort.

A major susceptibility locus for leprosy in India maps to chromosome 10p13.

Leprosy, a chronic infectious disease caused by Mycobacterium leprae, is prevalent in India, where about half of the world's estimated 800,000 cases occur. A role for the genetics of the host in variable susceptibility to leprosy has been indicated by familial clustering, twin studies, complex segregation analyses and human leukocyte antigen (HLA) association studies. We report here a genetic linkage scan of the genomes of 224 families from South India, containing 245 independent affected sibpairs with leprosy, mainly of the paucibacillary type. In a two-stage genome screen using 396 microsatellite markers, we found significant linkage (maximum lod score (MLS) = 4.09, P < 2x10-5) on chromosome 10p13 for a series of neighboring microsatellite markers, providing evidence for a major locus for this prevalent infectious disease. Thus, despite the polygenic nature of infectious disease susceptibility, some major, non-HLA-linked loci exist that may be mapped through obtainable numbers of affected sibling pairs.

Genomic characterization of Mycobacterium lepromatosis from ENL patients from India.

BACKGROUND: Leprosy is caused by Mycobacterium leprae and Mycobacterium lepromatosis. Both organisms cannot be cultured in vitro. M. lepromatosis was found to be associated mainly with diffuse lepromatous leprosy and with Lucio's phenomena initially. Later, M. lepromatosis was observed in borderline leprosy cases (BL), lepromatous leprosy cases (LL) and leprosy reactional cases (T1R and ENL). Although many cases are being reported with similar clinical features like Lucio phenomenon in India but M. lepromatosis was not isolated from these cases. The aim of this study was to screen MB patients and patients with type 2 reaction for the presence of M. lepromatosis. METHODOLOGY: We recruited a total of 75 multibacillary leprosy cases (45 MB cases without reaction and 30 type 2 reaction (ENL) cases) from TLM hospitals Purulia (West Bengal), Barabanki (Uttar Pradesh), Shahdara (Delhi) and PGIMER (Chandigarh), India. Punch biopsies of 5 mm were collected in 70% ethanol from all the study subjects. DNA was extracted followed by Hemi-nested PCR targeting 16S rRNA gene specific for M. lepromatosis. Further, PCR products were processed for Sanger sequencing for an absolute confirmation of M. lepromatosis. Whole genome sequencing was done to confirm the presence of M. lepromatosis. RESULT: We observed presence of M. lepromatosis in 4 necrotic ENL patients by heminested PCR. There was 100% 16S rRNA sequence similarity with M. lepromatosis FJ924 in one case, 98.96% in two cases and in one case it was 90.9% similarity by nucleotide BLAST (BLASTn) by using the NCBI website. On the basis of Sanger sequencing, we noted presence of M. lepromatosis in 3 necrotic ENL patients as one sample only gave 90.9% similarity by BLASTn. On the basis of de novo assembly and genome obtained, only one sample S4 with a 2.9 mb genome size was qualified for downstream analysis. Sixteen M. lepromatosis- specific proteins were identified in this case and the closest species was M. lepromatosis strain FJ924 based on whole genome level phylogeny. CONCLUSION: These results provide valuable insights into the prevalence of M. lepromatosis in ENL patients in different regions of India and contribute to our understanding of the genetic characteristics of this pathogen in the context of leprosy.

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

PURPOSE: Leprosy is a chronic infectious disease caused by Mycobacterium leprae affecting mainly skin and peripheral nerves. Acute inflammatory episodes in the borderline immunological spectrum of the disease cause severe nerve and tissue damage leading to deformities. Finding of any serological marker for leprosy reactions will help in prediction of reactions and in early treatment intervention. The objective of this study was to measure the serum circulatory levels of Interleukin 17F (IL 17F) and to correlate the levels with type 1 and type 2 reactional states and with clinico-histopathological spectrum of leprosy. We studied IL 17F to delineate its role and its clinical implications in leprosy reactions. METHODS: Patients were classified based on the Ridley DS and Jopling WH Classification and blood samples (5 ml each) were collected from 80 active untreated leprosy cases in Type 1 reaction (T1R), 21 cases in Type 2 (Erythema Nodosum Leprosum ENL) reaction (T2R), 80 cases without reaction (NR), and 94 non-leprosy cases (NL). Serum was separated and measured for IL 17F levels using ELISA (Commercial Kits, R&D Systems Inc., USA). RESULTS: IL 17F levels were significantly higher in the T1R group when compared to the NR group (p < 0.001). The borderline lepromatous group showed the highest levels of IL 17F among the other groups in the disease spectrum. Bacteriological index (BI) showed negative correlation with the IL 17F levels. CONCLUSION: The results specify that serum circulatory levels of IL 17F are elevated during T1Rs in the borderline spectrum of the disease and thus may play a role in the regulation of inflammatory responses associated with reactions in leprosy.

Formation of immunoglobulin light chain amyloid oligomers in primary cutaneous nodular amyloidosis.

BACKGROUND: Primary cutaneous nodular amyloidosis (PCNA) is thought to be a plasma cell dyscrasia. The amyloid deposits are found in the dermis and subcutis, and they contain clonal immunoglobulin light chains, produced by a local proliferation of plasma cells. New insights into amyloid diseases have revealed that the pathology is due more to the presence of small, misfolded protein species termed oligomers than to the deposition of fibrillar material. OBJECTIVES: To demonstrate the presence of amyloid oligomers in PCNA and to provide evidence that cutaneous amyloid diseases share a common pathogenic pathway similar to other amyloid diseases. METHODS: Immunohistochemical staining with conformation-specific and sequence-specific antibodies was used to localize different amyloid species of light chain immunoglobulins in a case of PCNA. Additionally, in vitro characterization of immunoglobulin oligomers and fibrils was performed to determine, through toxicity studies in a human keratinocyte cell line, which amyloidogenic form of the immunoglobulin is toxic in PCNA. RESULTS: Amyloid oligomers were identified in PCNA. Oligomers were mainly formed by lambda light chain immunoglobulins, and kappa light chain oligomers were detected in lesser amounts. Amyloid species were detected intra- and extracellularly. In addition, amyloid oligomers and fibrils, derived from unknown protein sources, were detected. This finding suggests that immunoglobulin amyloids can act as seeds capable of inducing the aggregation of heterogeneous proteins in the skin. Furthermore, cytotoxicity studies demonstrated that immunoglobulin oligomers, but not monomers or fibrils, are toxic to human keratinocytes. CONCLUSIONS: These data indicate that PCNA has common pathways with other amyloid diseases with respect to protein misfolding and pathogenesis. Immunoglobulin oligomers may prove to be targets for the treatment of PCNA.

Proteomic analysis of outer membrane proteins of Edwardsiella tarda.

AIMS: The purpose of this study was to identify outer membrane proteins (OMPs) of Edwardsiella tarda. METHODS AND RESULTS: The OMPs from a virulent strain of E. tarda (ET-7) was extracted using lauroyl sarcosine method. The OMPs were analysed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), and protein spots were identified using matrix assisted laser desorption/ionization-time-of-flight mass spectrometry. A total of 21 proteins were identified from 24 protein spots observed on the 2D-PAGE gel. These proteins were identified as GroEL, antigenic proteins, ABC transporters, elongation factors, OmpA, PTSINtr with GAF domain, catalase C, glycolytic enzymes, DnaJ, transcriptional regulator, proteins mraZ and ccdA. Subcellular localizations, beta-barrel OMPs and lipoproteins of identified proteins were predicted using PSORTb, PRED-TMBB and LipoP1.0 programme. CONCLUSIONS: Identification, localization and possible functions of OMPs of E. tarda were studied. SIGNIFICANCE AND IMPACT OF THE STUDY: These proteins could be used for development of novel drug targets, diagnostics or vaccine against edwardsiellosis.

Survival of Mycobacterium leprae and association with Acanthamoeba from environmental samples in the inhabitant areas of active leprosy cases: A cross sectional study from endemic pockets of Purulia, West Bengal.

BACKGROUND: Mycobacterium leprae being an obligate intracellular parasite cannot be cultured in any artificial culture media but it has been shown to reside in wild armadillos in North America. Many studies suggested that M. leprae could be found in the environment and may have a role in continuing transmission of the disease. The exact role of the environment in the transmission dynamics is still speculative. The present study was undertaken to find out the presence of viable M. leprae around patients' environment like soil and water and association of free living pathogenic protozoa, Acanthamoeba which might play an important role in transmission of the disease. METHODS: Seven hundred soil and 400 water samples were collected from the surroundings of the houses of leprosy patients from endemic villages. Two hundred soil and 80 water samples were also collected from the surroundings of normal inhabitants from non-endemic villages as controls. These samples were screened for the presence of M. leprae and Acanthamoeba using DNA PCR. RNA was extracted from the PCR positive samples and Reverse Transcriptase - PCR targeting 16S rRNA gene region was performed for detection of viable M. leprae. RESULTS: We observed high PCR positivity in soil samples (218 out of 700; 31%) and water samples (73 out of 400; 18%). These samples when further screened for viability, it was observed that 106 soil samples (15% of total) and 34 water samples (8% of total) showed presence of 16S rRNA. We observed 18.3% of soil and 20.5% of water samples were PCR positive for Acanthamoeba. Soil samples from the control area, where no active leprosy case resided in the last 5 years, showed PCR positivity in 4 samples (2%) for M. leprae DNA in only soil samples with all water samples being negative. RT-PCR for all PCR positive soil samples was negative. Of the 106 soil samples positive for M. leprae RT-PCR, 30 samples were also positive for Acanthamoeba whereas out of 112 M. leprae RT-PCR negative but PCR positive samples only 10 samples were Acanthamoeba positive showing association of viability with presence of Acanthamoeba (p = .0021). Similarly, for water samples also, association of M. leprae viability with presence of Acanthamoeba was seen (p = .0009). CONCLUSION: This study suggests that the surrounding environment (soil and water) of leprosy patients contain viable M. leprae and the viability has association with Acanthamoeba which may provide a protective niche for M. leprae. This could play an important role in the focal transmission of the disease.

Diagnostic potential of Ag85C in comparison to various secretory antigens for childhood tuberculosis.

Childhood tuberculosis is difficult to diagnose. A rapid, simple and relatively inexpensive diagnostic test will be crucial to future control efforts. Therefore, efficacy and diagnostic potential of different secretory antigens of Mycobacterium tuberculosis (CFP-10, Ag85complex, Ag85 A, B, C) and their combinations along with ESAT-6 in the detection of antibody profiles of childhood tuberculosis cases were evaluated using ELISA technique and reactivity was compared with the gold standards (smear, culture and IS6110 targeted PCR). In the present study, 88 fresh, untreated childhood tuberculosis (TB) cases, 17 children undergoing anti-tubercular therapy, 17 children having disease other than TB and 25 healthy children were included. ROC curve analysis was used to calculate the sensitivity and specificity of each antigen for antibody detection. Ag85C was found to be showing highest sensitivity of 89.77% and specificity of 92% among all the antigens used (P < 0.0001). Positivity with antigen was 95% in smear and culture negative patients. Antibody reactivity was noted in 92.62% of patients who were positive for IS6110 by PCR. Cocktail of all the antigens showed 67.1% sensitivity and 80% of specificity. Sensitivity of 29.55%, 57.95%, 64.77% and specificity of 80%, 72%, 64% was observed using CFP-10, Ag85complex and Ag85B. Low reactivity of 31.82% in patients and least specificity of 24% was noted with Ag85A. Our finding demonstrates the potential of Ag85C in the detection of antibody in childhood TB cases and this antigen showed good concordance with PCR positivity.

Seroprevalence of HIV infection among paediatric tuberculosis patients in Agra, India: a hospital-based study.

In this study which was carried over a period of 2 years, from 2003 to 2004, 270 paediatric patients with active Tuberculosis (TB) disease attending the OPD of S.N. Medical College, Agra were screened for Human Immunodeficiency Virus (HIV)-1/2 antibodies. Of these, 23 were found to be HIV-positive. Seroprevalence of HIV infection among paediatric TB patients in Agra is 8.51% (23/270). The HIV infection was found to be significantly higher, i.e. 82.61% in male children than in female children, i.e. 17.39%. Among the age groups, which were divided into < or =1, 2-5, 6-10 and 11-15 years, maximum cases of HIV-positivity, i.e. 65.22% was observed in the age group, 2-5 years of age. Among the HIV-positive children with TB, 86.75% were of pulmonary and 13.04% were of extra-pulmonary type. Among the vaccinated children, 65.22% were found to be HIV-positive, while 34.78% of the HIV-positive children were not BCG vaccinated. HIV-positive children are more likely to suffer from prolonged fever, weight loss, failure to thrive, developmental delay, stunted growth, cough, anorexia, lethargy, lower respiratory tract infections (LRTI) and hepatosplenomegaly while HIV negative are more likely to suffer from fever, diarrhoea, lymphadenitis, pallor and LRTI. 82.60% (19/23) of these TB patients had a history of positive contact with HIV, i.e. one of the parents was HIV-infected. The mode of transmission of HIV infection among paediatric TB patients was perinatal as revealed during the counselling sessions (pre-test and post-test) of both the parents.

Increased level of urinary nitric oxide metabolites in leprosy patients during type 2 reactions and decreased after antireactional therapy.

OBJECTIVES: To assess the urinary nitric oxide metabolites in lepromatous patients in ENL (type 2 reactions) and to compare these metabolites after subsidence of reactions following antireactional therapy. Further to compare the levels in a group of lepromatous leprosy patients without reactions. DESIGN: The initial urine samples were collected from lepromatous leprosy patients when they came with ENL before commencing antireactional therapy and repeat samples were taken after resolution of ENL. Morning urine samples were collected from LL patients without reactions. Nitrites and nitrates in urine were measured using commercially available kit. Mean levels of nitric oxide metabolites of LL patients with ENL and without ENL were compared by student's 't' test. The level during ENL and after resolution was compared by paired 't' test. RESULTS: The nitric oxide metabolites were analyzed in 14 LL patients with ENL and after resolution of ENL and in 5 LL patients without reaction. The level of urinary nitric oxide metabolite is higher in LL patients in ENL reaction compared to LL patients without reaction (P < 0.04). These levels were reduced significantly with resolution of reaction following antireactional therapy (P < 0.004). CONCLUSION: The findings of this study suggested that the NO/NOM excretion is increased in leprosy patients during ENL episodes. With antireactional therapy (steroids) and clinical improvement the levels are reduced.

Serum samples from patients with mycobacterial infections cross-react with HIV structural proteins Gp41, p55 and p18.

BACKGROUND: Infection with Mycobacterium leprae is associated with a high frequency of false positive results in a variety of serological assays. Our studies have found cross-reactivity to HIV structural proteins in serum samples from leprosy patients, irrespective of the type of disease, treatment duration, age and gender and from a few patients with active TB disease. METHODS: Western blot (WB) analysis revealed that sera from HIV negative leprosy patients across the spectrum showed high reactivity with p18, Gp41 and p55 and lower reactivity with other HIV proteins. The reactivity appeared to be specific; western blot-positive samples were negative in ELISA and in several rapid tests for HIV. Cross-reactivity was not found in sera from patients with leishmaniasis or from normal healthy individuals. RESULTS: None of the WB reactive leprosy patients seroconverted to HIV positivity within 6 months to 1 year after Western blot testing. BLAST analysis revealed that envelope antigens of HIV (Gp41, Gp120 and Gp160) contained amino acid sequences similar to M. leprae ML0470, putative integral membrane protein, Rv0740, mmpL9 (M. tuberculosis). Core (gag) antigens (p18) had similarities to ML0406, but polymerase antigens (p52) had similarities to PE_PGRS (M. tuberculosis, H37Rv). Nucleotide sequence analysis, on the other hand, did not reveal any significant homology between M. leprae or M. tuberculosis and HIV. CONCLUSIONS: The occurrence of these high false-positive rates in M. leprae-infected individuals suggests a possible complication of serodiagnosis of HIV in regions where mycobacterial infections are endemic. There is a need for caution in reporting HIV infection among leprosy patients. Our observations emphasise the value of the various rapid assay kits for HIV, where this false positivity is not observed.

Seroprevalence of HIV infection among tuberculosis patients in Agra, India--a hospital-based study.

In this study which was carried over a period of 4 years, from 2001 to 2004, 600 adult patients with active TB disease attending the OPD of TBDTC, Agra, were screened for HIV-1/2 antibodies. Of these, 26 were found to be HIV-positive. Seroprevalence of HIV infection among adult TB patients in Agra is 4.3% (26/600). The HIV infection was found to be more in females, i.e. 7.95% (7/88) than in males, 3.71% (19/512). HIV-positivity of 5% was observed in the age groups, 15-24 and 25-34 years, i.e. 3/60 and 13/260, respectively. Among HIV-positive TB patients, 4.2% (22/524) were of pulmonary and 5.3% (4/76) were of extra-pulmonary type. A total of 3.04% (6/197) of HIV-positive TB patients were PPD positive and 4.96% (20/403) were PPD negative and bacillary positivity was 4.4% (15/340) and bacillary negativity was 4.2% (11/260). A total of 3.5% (18/515) of TB patients had a history of positive contact, i.e. spouse or one of the family members was HIV-infected. The difference in signs and symptoms among the HIV positive and HIV negative TB patients was found to be statistically significant.

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

PURPOSE: Leprosy is a chronic systemic infectious disease caused by Mycobacterium leprae, one of the first organisms to be established as the cause for disease in humans. Because of high prevalence pockets of leprosy in the endemic regions, it is necessary to identify the possible sources of M. leprae in the environment and its mode of transmission. MATERIALS AND METHODS: Slit skin smears (SSSs) from lesions were collected in 70% ethanol from 50 leprosy cases staying in the leprosy resettlement village and hospital from a high endemic area. One hundred and sixty soil samples were collected from different areas around the leprosy hospital and from the resettlement village of cured leprosy patients where active cases also resided at the time of sample collection. M. leprae specific gene region (RLEP 129 bp) and 16S rRNA targets were used for polymerase chain reaction (PCR) based detection for the presence and viability of M. leprae. An rpoT region was also amplified to determine presence of numbers of 6 bp tandem repeats. RESULTS: All the SSS samples collected from patients showed three copies of rpoT region (6 bp tandem repeat, an ancient Indian type). Fifty-two soil samples showed presence of M. leprae DNA whereas M. leprae specific 16S rRNA gene was amplified in sixteen of these samples. PCR amplification and fragment length analysis showed 91 bp, i.e., three copies of the rpoT 6 bp tandem repeats from soil samples and similar three copies observed in patient samples. CONCLUSION: Presence of viable M. leprae in the soil having same rpoT genotype of M. leprae noted in patients suggests that it could be the same strain of M. leprae. M. leprae found in the soil could be the one that is excreted out by the patient. Significance of its viability in the environment and its pathogenicity with respect to transmission needs to be further explored. Findings of this study might provide possible insights for further exploration into understanding transmission patterns in leprosy and also will throw light on identifying potential for existence of extra human source or reservoirs of M. leprae, if any.

Seroprevalence of HIV infection among the foreign students at Agra during a fifteen year period (1988-2002).

The present study reports a retrospective analysis of data of HIV testing of foreign students from Sub-Saharan Africa, South-East Asia and Europe, studying as well as staying at Agra, over a period of 15 yr (1988 to 2002). Of the 2653 [2092 (78.85%) were from the Sub-Saharan African countries, 377 (14.21%) from the South-East Asian countries, and 184 (6.93%) from the European countries], foreign students tested for HIV, only 26 were found to be positive for HIV-1/2 antibodies by the ELISA, rapid and Western Blot assays. Out of 26 HIV-positive, 17 males and 7 females were from Sub-Saharan Africa and 2 males were from the European countries. The range of HIV-positivity over a period of 15 yr varied greatly. When the five-year (1988-1992, 1993-1997 and 1998-2002) results were compared, the HIV-seropositivity showed a decline from 1.85, 0.50 to 0.36 per cent in the first, second and third 5 yr slots, respectively. While the data were not representative of all foreign students in India, this reflected the population tested in this centre was not a growing focus of HIV infection in this part of the country.

Genotyping of Mycobacterium leprae strains from a region of high endemic leprosy prevalence in India.

Leprosy is still a major health problem in India which has the highest number of cases. Multiple locus variable number of tandem repeat analysis (MLVA) and single nucleotide polymorphism (SNP) have been proposed as tools of strain typing for tracking the transmission of leprosy. However, empirical data for a defined population from scale and duration were lacking for studying the transmission chain of leprosy. Seventy slit skin scrapings were collected from Purulia (West Bengal), Miraj (Maharashtra), Shahdara (Delhi), and Naini (UP) hospitals of The Leprosy Mission (TLM). SNP subtyping and MLVA on 10 VNTR loci were applied for the strain typing of Mycobacterium leprae. Along with the strain typing conventional epidemiological investigation was also performed to trace the transmission chain. In addition, phylogenetic analysis was done on variable number of tandem repeat (VNTR) data sets using sequence type analysis and recombinational tests (START) software. START software performs analyses to aid in the investigation of bacterial population structure using multilocus sequence data. These analyses include data summary, lineage assignment, and tests for recombination and selection. Diversity was observed in the cross-sectional survey of isolates obtained from 70 patients. Similarity in fingerprinting profiles observed in specimens of cases from the same family or neighborhood locations indicated a possible common source of infection. The data suggest that these VNTRs including subtyping of SNPs can be used to study the sources and transmission chain in leprosy, which could be very important in monitoring of the disease dynamics in high endemic foci. The present study strongly indicates that multi-case families might constitute epidemic foci and the main source of M. leprae in villages, causing the predominant strain or cluster infection leading to the spread of leprosy in the community.

In situ demonstration of Mycobacterium leprae antigens in leprosy lesions using monoclonal antibodies.

Cryostat sections of skin and nerve lesions of leprosy were stained with monoclonal antibodies recognising Mycobacterium leprae antigens and indirect immunofluorescence. In both the tuberculoid and lepromatous lesions, PGL1, 55-65-kDa, 17-kDa protein antigens and cross-reactive non-protein antigens were present. 65-kDa antigens were seen mainly in the skin lesions of lepromatous leprosy. The infiltrates in both the skin and nerve granulomas of tuberculoid and lepromatous leprosy showed membranous staining with monoclonal antibodies recognising PGL1 and 55-65-kDa antigens. Bacilli in the lesions and the cells in the lymph node granulomas of patients with tuberculosis or the infiltrates in the lesions of tinea corporis or sections of normal skin did not show any staining with these monoclonal antibodies. These results confirm that M. leprae antigens are present and are expressed on the infiltrating cells of leprosy lesions.

Detection of antibodies against phenolic glycolipid-1 (PGL-1), 35-kDa and 30-40-kDa components of Mycobacterium leprae in the cerebrospinal fluid of of leprosy patients.

The involvement of the central nervous system (CNS) in lepromatous leprosy (LL) patients was investigated; 33 patients were examined clinically in detail and upper motor neuron involvement was observed in eight and lower motor neuron in three of these patients. Anti-Mycobacterium leprae antibodies could be detected in the CSF by PGL-1 enzyme-linked immunosorbent assay (ELISA) and monoclonal antibody (MAb) based competitive assays against defined epitopes on the 35-kDa protein and 30-40-kDa polysaccharide (lipoarabinomannan) antigens with MAbs MLO4 and ML34, respectively. Antibodies against PGL-1 and 35-kDa protein were observed in more subjects than antibodies against the 30-40-kDa antigen. Some correlation was observed between the upper motor neuron signs and antibody positivity for 35-kDa and PGL-1 antigens in the CSF of these patients.

A serological test for leprosy based on competitive inhibition of monoclonal antibody binding to the MY2a determinant of Mycobacterium leprae.

A novel serological assay for leprosy has been devised on the basis of serum inhibition of binding of 125I-labelled ML04 monoclonal antibody to Mycobacterium leprae sonicate-coated microtitre plates. Antibodies were detected in 93% of lepromatous leprosy patients, whereas controls from the endemic area, including leprosy contacts and patients with tuberculosis, were serologically negative. The specificity and efficacy of the test may offer an advantage over previously used techniques.

Experience and lessons from the use of lepromin and Mycobacterium leprae-specific serology.

Skin testing with lepromin, which produces a delayed-type hypersensitivity reaction, has been used in the classification of leprosy, and a good correlation has been found between immunological status and the reaction to lepromin. In addition, the prognostic value of the lepromin test has been demonstrated. More recently, skin testing with two soluble antigens of Mycobacterium leprae showed no difference of the mean size of the reaction between household contacts and non-contacts, indicating that these antigens are not useful for the diagnosis of leprosy. This and other evidence points to the need for a better skin test antigen capable of detecting infection of individuals by M. leprae. Whereas serological assays for antibodies against both PGL-1 and the 35 kDa antigen of M. leprae have been found to yield positive results in 90-100% of patients with lepromatous (BL/LL) leprosy, these assays fail to identify 40-60% of patients with tuberculoid (BT/TT) leprosy, because of the presence of only an insignificant level of antibody against components of M. leprae in these patients' serum, although, in many BT patients, antibody signal could be detected in the local lesions. These data indicate that there remains a need for a specific diagnostic test for leprosy.