Insights from the sequence similarity of Zika virus proteins with the Human nerve proteins.

Massive peptide sharing between the Zika virus polyprotein and host tissue proteins could elicit significant host-pathogen interactions and cross-reactions leading to autoimmune diseases. This study found similarities in the Zika V proteins and human nerve tissue proteins. 63 human nerve proteins were screened for similarities with the Zika V of which Neuromodulin, Nestin, Galanin, Bombesin, Calcium-binding protein were found to have similarities to the Zika V poly protein C at different sequence regions. These sequence similarities could be significant in regulating pathogenic interactions/autoimmunity, as Polyprotein C is known to be a virulent factor.

High-Resolution Sonography as an Additional Diagnostic and Prognostic Tool to Monitor Disease Activity in Leprosy: A Two-Year Prospective Study.

PURPOSE: Early diagnosis and treatment of leprosy and leprosy reactions are essential to prevent stigmatizing deformities and disability. Although the incidence of leprosy has decreased enormously, grade 2 disability due to nerve injury has remained the same. New tools are needed to better diagnose and monitor leprosy reactions and associated neuritis and this study assessed whether high-resolution sonography (HRUS) can be used as such a tool. MATERIALS AND METHODS: During a prospective follow-up period of 2 years at regular intervals, we performed clinical examination to assess sensory and motor function and HRUS of the four main peripheral nerves in 57 patients, of whom 36 were with reactions and 21 were without reactions. Normative data of the cross-sectional area (CSA) of these nerves were obtained from 55 healthy subjects (HS). Color Doppler (CD) was used to study blood flow in the nerves. RESULTS: At the baseline visit and during follow-up, all four nerves were significantly thicker in patients with leprosy reactions in comparison to HS (p < 0.0001) and to a lesser extent also in comparison to patients without reactions ranging from a p-value of < 0.05 to < 0.0001 in the different nerves tested. During follow-up, the nerve size did not change significantly in patients without reactions, while it decreased significantly in patients with reactions. At baseline, endoneural blood flow was present only in patients with reactions. This occurred in 20 of the 36 (55 %) patients (49 nerves) and decreased to only 1 patient (2.7 %) at the end of the follow-up period. CONCLUSION: This prospective study demonstrates the ability of HRUS to monitor disease activity and the effect of treatment in patients with leprosy reactions by determining changes in nerve size and vascularity, which are indicators of peripheral nerve involvement and damage.

Anticeramide antibody and butyrylcholinesterase in peripheral neuropathies.

Ceramide is a glycosphingolipid, a component of nerve and non neuronal cell membrane and plays a role in maintaining the integrity of neuronal tissue. Butyrylcholinesterase (BChE) is a multifunctional enzyme, its involvement in neurodegenerative diseases has been well established. Anticeramide antibody (Ab-Cer) and enzyme BChE have been implicated in peripheral neuropathies. The present study investigates whether there is an association between Ab-Cer and BChE activities and peripheral neuropathies. Patients included: human immunodeficiency virus associated peripheral neuropathy (HIV-PN, n=39), paucibacillary leprosy (PB-L, n=36), multibacillary leprosy (MB-L, n=52), diabetic neuropathy (DN, n=22), demyelinating sensory motor polyneuropathy (DSMN, n=13) and chronic inflammatory demyelinating polyneuropathy (CIDP, n=10). Plasma Ab-Cer was measured by indirect enzyme linked immune assay (ELISA) and BChE activity in plasma was measured by colorimetric method. Ab-Cer levels were significantly elevated in MB-L and DN as compared to healthy subjects (HS). BChE levels were significantly higher in MB-L and DN as well as in HIV and HIV-PN. There is no significant difference in either Ab-Cer or BChE levels in DSMN and CIDP. Elevated plasma Ab-Cer and BChE levels may be considered significant in the pathogenesis of neuropathies. The variation in concurrent involvement of both the molecules in the neuropathies of the study, suggest their unique involvement in neurodegenerative pathways.

High levels of plasma interferon gamma and +874T/A gene polymorphism is associated with HIV-TB co-infection.

OBJECTIVE: Tuberculosis (TB) is one of the most frequent opportunistic infections in HIV patients leading to increased morbidity and death rate. This study was carried out to investigate the role of the cytokines IFN-γ and TNF-α level and their single nucleotide polymorphisms (SNPs) in HIV-TB co-infection. METHODS: 247 HIV-TB (124 HIV-pulmonary TB, 123 HIV-extra pulmonary TB), 126 HIV positive individuals without tuberculosis and 129 healthy subjects (HS) were included to measure plasma levels of IFN-γ and TNF-α by sandwich ELISA and One way ANOVA statistical analysis was carried out among the groups. The SNPs of TNF-α-308 G/A, -238 G/A and IFN-γ+874 T/A were also investigated using amplification refractory mutation system polymerase chain reaction (ARMS-PCR). The frequencies between the groups were compared by Pearson's chi square statistical analysis. RESULTS: Plasma IFN-γ and TNF-α were significantly elevated in HIV-TB and TB (p<0.05) as compared to those in HS group. There was significant association between IFN-γ+874 'A' allele and AA genotype in HIV-TB groups compared to HS and HIV (p<0.05) and no such association was found for TNF-α-308 and -238. The plasma cytokine levels of TNF-α and IFN-γ reveals no significant association with levels of IFN-γ+874 T/A, TNF-α -308 G/Aand-238 G/A genotypes in any of the study groups. CONCLUSION: In conclusion, the present study revealed elevated plasma IFN-γ and its +874 'A' allele are associated with HIV-TB co-infection indicating 1.6 times increased risk for TB susceptibility. Elevated TNF-α levels in TB and HIV-TB suggest its involvement in TB pathogenesis.

Detection of Tuberculosis in HIV Co-infected Individuals: Use of Multiple ELISA Responses to 38kDa, Lipoarabinomannan and ESAT- 6 of M. tuberculosis.

INTRODUCTION: There is a constant search for more sensitive and specific laboratory markers for tuberculosis (TB) infection. The early detection of TB in HIV co infected individuals is a diagnostic challenge. This is further compounded in those harbouring extrapulmonary disease. AIM: To evaluate the use of multiple Enzyme Linked Immunosorbent Assays (ELISA) quantifying antibody responses to 38kDa, LAM and ESAT-6 M.tb antigens in detection of TB in patients with TB and HIV-TB co-infection. MATERIALS AND METHODS: This is a cross-sectional study carried out in Hyderabad, India. Patient groups included 124 HIV-TB {62 with pulmonary TB (PTB) and 62 with extrapulmonary TB (ETB)}, 39 TB, 56 HIV and 57 healthy subjects (HS). A combination of anti 38kDa and LAM ELISAs measuring IgG, IgM and IgA levels and another ELISA measuring anti ESAT-6 combined antibody levels of IgG, IgM and IgA were evaluated. One-way ANOVA was performed to compare antibody responses among groups. To assess the efficacy of multiple ELISAs in detecting TB, concomitant seropositivity of an individual for all four ELISAs were evaluated for sensitivity and specificity. RESULTS: A single ELISA carried out to detect TB in HIV patients showed a sensitivity ranging from 39% to 72%. The sensitivities of concomitant evaluation of multiple ELISAs were 92% for any single, 72% for any two, 44% for any three and 14% for any four. Based on the specificities, a simple algorithm for TB detection can be deduced. When four ELISAs are positive (specificity 100%) in a patient-confirmed TB; when three ELISAs are positive (specificity 98%) - probably TB; when two ELISAs are positive (specificity 95%) - possibly TB; and when one ELISA is positive (specificity 70%) - suspicion of TB. CONCLUSION: The present study establishes the value of combining two or more M.tb antigen based ELISAs to enhance the sensitivity and specificity of TB detection in patients with tuberculosis as well as in those co-infected with HIV.

Association of tumor necrosis factor-alpha and interferon gamma gene polymorphisms and their plasma levels in leprosy, HIV and other peripheral neuropathies.

OBJECTIVE: Mycobacterium leprae and Human Immunodeficiency Virus (HIV) are causative agents known to be involved in nerve damage in leprosy and HIV-peripheral neuropathy (HIV-PN) respectively. Among other peripheral neuropathies the most common is diabetic neuropathy, which is metabolically induced. The proinflammatory cytokines TNF-α and IFN-γ have been implicated in the pathogenesis of peripheral neuropathy. The association between the plasma levels of these cytokines and their single nucleotide polymorphisms (SNPs) were investigated in leprosy neuropathy (LN), HIV-PN and other peripheral neuropathies (OPN). METHODS: Eighty-eight individuals with LN (PB=36; MB=52), 39 with HIV-PN, 52 patients with OPN, 101 HIV positive individuals without neuropathy (HIV) and 113 healthy subjects (HS) were included in the study. Plasma cytokine levels were measured by sandwich ELISA and one way ANOVA was carried out among the groups. SNPs of TNF-α- 308 G/A, -238 G/A and IFN-γ +874 T/A were investigated by amplification refractory mutation system polymerase chain reaction (ARMS-PCR). Their frequencies were compared between groups by Pearson's chi squared test. RESULTS: Plasma TNF-α and IFN-γ was significantly increased in LN (p<0.05), HIV-PN (p<0.05) and OPN (p<0.05) as compared to HS. A significant association was found between IFN-γ +874 A/A genotype in LN (p<0.05; OR=7.9), HIV-PN (p<0.05; OR=8.9) and OPN (p<0.05; OR=8.9) as compared to HS. CONCLUSION: Elevated levels of plasma TNF-α and IFN-γ and the association of IFN-γ +874 A/A genotype SNP in LN, HIV-PN and OPN suggests a common involvement of these cytokines in susceptibility/pathogenesis of peripheral neuropathy.

Relationship of long-term highly active antiretroviral therapy on salivary flow rate and CD4 Count among HIV-infected patients.

OBJECTIVES: To determine if long-term highly active antiretroviral therapy (HAART) therapy alters salivary flow rate and also to compare its relation of CD4 count with unstimulated and stimulated whole saliva. MATERIALS AND METHODS: A cross-sectional study was performed on 150 individuals divided into three groups. Group I (50 human immunodeficiency virus (HIV) seropositive patients, but not on HAART therapy), Group II (50 HIV-infected subjects and on HAART for less than 3 years called short-term HAART), Group III (50 HIV-infected subjects and on HAART for more than or equal to 3 years called long-term HAART). Spitting method proposed by Navazesh and Kumar was used for the measurement of unstimulated and stimulated salivary flow rate. Chi-square test and analysis of variance (ANOVA) were used for statistical analysis. RESULTS: The mean CD4 count was 424.78 ± 187.03, 497.82 ± 206.11 and 537.6 ± 264.00 in the respective groups. Majority of the patients in all the groups had a CD4 count between 401 and 600. Both unstimulated and stimulated whole salivary (UWS and SWS) flow rates in Group I was found to be significantly higher than in Group II (P < 0.05). Unstimulated salivary flow rate between Group II and III subjects were also found to be statistically significant (P < 0.05). ANOVA performed between CD4 count and unstimulated and stimulated whole saliva in each group demonstrated a statistically significant relationship in Group II (P < 0.05). There were no significant results found between CD4 count and stimulated whole saliva in each groups. CONCLUSION: The reduction in CD4 cell counts were significantly associated with salivary flow rates of HIV-infected individuals who are on long-term HAART.

Insights from the predicted epitope similarity between Mycobacterium tuberculosis virulent factors and its human homologs.

Mycobacterium tuberculosis is known to be associated with several autoimmune diseases such as systemic lupus erythematous, rheumatoid arthritis and multiple sclerosis. This is attributed to sequence similarity between virulent factors and human proteins. Therefore, it is of interest to identify such regions in the virulent factors to assess potential autoimmune related information. M. tb specific virulent factors were downloaded from the VFDB database and its human homologs were identified using the sequence comparison search tool BLASTP. Both virulent proteins and their corresponding human homologs were further scanned for epitopes (B cell and HLA class I and II allele specific) using prediction programs (BCPRED and NETMHC). Data shows the presence of matching 22 B-cell, 79 HLA class II and 16 HLA class I specific predicted epitopes in these virulent factors having human homologs. A known peptide (HAFYLQYKNVKVDFA) associated with autoimmune atopic dermatitis is shown in the superoxide dismutase homolog structures of the bacterium (PDB ID: 1IDS) and human (PDB ID: 2QKC). This data provides insight into the understanding of infection-associated auto-immunity.

Serological responses to prednisolone treatment in leprosy reactions: study of TNF-α, antibodies to phenolic glycolipid-1, lipoarabinomanan, ceramide and S100-B.

BACKGROUND: Corticosteroids have been extensively used in the treatment of immunological reactions and neuritis in leprosy. The present study evaluates the serological response to steroid treatment in leprosy reactions and neuritis. METHODS: Seven serological markers [TNF-α, antibodies to Phenolic glycolipid-1 (PGL-1 IgM and IgG), Lipoarabinomannan (LAM IgG1 and IgG3), C2-Ceramide and S100 B] were analyzed longitudinally in 72 leprosy patients before, during and after the reaction. At the onset of reaction these patients received a standard course of prednisolone. The levels of the above markers were measured by Enzyme linked immunosorbent assay (ELISA) and compared with the individuals own value in the month prior to the reaction and presented as percentage increase. RESULTS: One month before the reaction individuals showed a varying increase in the level of different markers such as TNF-α (53%) and antibodies to Ceramide (53%), followed by to PGL-1 (51%), S100B (50%) and LAM (26%). The increase was significantly associated with clinical finding of nerve pain, tenderness and new nerve function impairment. After one month prednisolone therapy, there was a fall in the levels [TNF-α (60%), C2-Ceramide (54%), S100B (67%), PGL-1(47%) and LAM (52%)] with each marker responding differently to steroid. CONCLUSION: Reactions in leprosy are inflammatory processes wherein a rise in set of serological markers can be detected a month before the clinical onset of reaction, some of which remain elevated during their action and steroid treatment induces a variable fall in the levels, and this forms the basis for a variable individual response to steroid therapy.

Cytokine and protein markers of leprosy reactions in skin and nerves: baseline results for the North Indian INFIR cohort.

BACKGROUND: Previous studies investigating the role of cytokines in the pathogenesis of leprosy have either been on only small numbers of patients or have not combined clinical and histological data. The INFIR Cohort study is a prospective study of 303 new multibacillary leprosy patients to identify risk factors for reaction and nerve damage. This study characterised the cellular infiltrate in skin and nerve biopsies using light microscopic and immunohistochemical techniques to identify any association of cytokine markers, nerve and cell markers with leprosy reactions. METHODOLOGY/PRINCIPAL FINDINGS: TNF-α, TGF-ß and iNOS protein in skin and nerve biopsies were detected using monoclonal antibody detection immunohistochemistry techniques in 299 skin biopsies and 68 nerve biopsies taken from patients at recruitment. The tissues were stained with hematoxylin and eosin, modified Fite Faraco, CD68 macrophage cell marker and S100. CONCLUSIONS/SIGNIFICANCE: Histological analysis of the biopsies showed that 43% had borderline tuberculoid (BT) leprosy, 27% borderline lepromatous leprosy, 9% lepromatous leprosy, 13% indeterminate leprosy types and 7% had no inflammation. Forty-six percent had histological evidence of a Type 1 Reaction (T1R) and 10% of Erythema Nodosum Leprosum. TNF-α was detected in 78% of skin biopsies (181/232), iNOS in 78% and TGF-ß in 94%. All three molecules were detected at higher levels in patients with BT leprosy. TNF-α was localised within macrophages and epithelioid cells in the granuloma, in the epidermis and in dermal nerves in a few cases. TNF-α, iNOS and TGF-ß were all significantly associated with T1R (p<0.001). Sixty-eight nerve biopsies were analysed. CD68, TNF-α and iNOS staining were detectable in 88%, 38% and 28% of the biopsies respectively. The three cytokines TNF-α, iNOS and TGF-ß detected by immunohistochemistry showed a significant association with the presence of skin reaction. This study is the first to demonstrate an association of iNOS and TGF-ß with T1R.

Analysis of antibody and cytokine markers for leprosy nerve damage and reactions in the INFIR cohort in India.

BACKGROUND: The ILEP Nerve Function Impairment in Reaction (INFIR) is a cohort study designed to identify predictors of reactions and nerve function impairment (NFI) in leprosy. AIM OF THE STUDY: Antibodies to mycobacteria, nerve components and serum cytokine were measured as potential markers for their possible association with reactions and NFI. PATIENTS AND METHODS: 303 newly diagnosed leprosy patients from two centres in North India were enrolled. Antibodies to PGL-1, LAM (IgG1 and IgG3), ceramide, S100 and TNFα levels were measured using ELISA techniques. RESULTS: S-100, PGL IgG and IgM antibody levels were lowest in patients with BT leprosy and highest in patients with lepromatous leprosy. LAM IgG1 and LAM IgG3 antibody levels were highest in patients with BL leprosy. Ceramide antibody levels were not correlated with type of leprosy. Levels of all the antibodies tested and TNF α were lowest in patients with only skin reaction. PGL IgM antibody levels were elevated in patients with skin reactions and NFI. Old sensory NFI is associated with significant elevation of PGL IgG, LAM IgG and S100 antibody levels. CONCLUSION: These results reveal that the antibody response to mycobacterial antigens, nerve antigens and cytokines are in a dynamic flux and could collectively contribute to NFI in leprosy. The association of multiple markers with old NFI may indicate the contribution of different pathological processes.

Antibodies to myelin P0 and ceramide perpetuate neuropathy in long standing treated leprosy patients.

Anti neural antibodies are known to play a role in the immunopathogenesis of nerve damage in leprosy and HIV/AIDS. Myelin Protein zero (P0) and ceramide are two nerve components which maintain the integrity of the peripheral nerve. The present study was undertaken to identify antibodies to myelin P0 and ceramide in the sera of treated leprosy patients, HIV positive individuals and healthy subjects using enzyme linked immunosorbant assay (ELISA). The results revealed that treated leprosy patients continue to have significantly elevated myelin P0 and ceramide antibody levels as compared to healthy subjects (P < 0.05). The elevated antibody response to myelin P0 and ceramide in leprosy patients indicate a low grade autoimmune activity that perpetuates nerve damage in treated leprosy. There was no significant difference in the myelin P0 and ceramide antibody levels between HIV positive and healthy subjects (P > 0.05) suggesting that these antibodies do not play a role in early HIV infection.

Predicting neuropathy and reactions in leprosy at diagnosis and before incident events-results from the INFIR cohort study.

BACKGROUND: Leprosy is a disease of skin and peripheral nerves. The process of nerve injury occurs gradually through the course of the disease as well as acutely in association with reactions. The INFIR (ILEP Nerve Function Impairment and Reactions) Cohort was established to identify clinically relevant neurological and immunological predictors for nerve injury and reactions. METHODOLOGY/PRINCIPAL FINDINGS: The study, in two centres in India, recruited 188 new, previously untreated patients with multi-bacillary leprosy who had no recent nerve damage. These patients underwent a series of novel blood tests and nerve function testing including motor and sensory nerve conduction, warm and cold detection thresholds, vibrometry, dynamometry, monofilament sensory testing and voluntary muscle testing at diagnosis and at monthly follow up for the first year and every second month for the second year. During the 2 year follow up a total of 74 incident events were detected. Sub-clinical changes to nerve function at diagnosis and during follow-up predicted these new nerve events. Serological assays at baseline and immediately before an event were not predictive; however, change in TNF alpha before an event was a statistically significant predictor of that event. CONCLUSIONS/SIGNIFICANCE: These findings increase our understanding of the processes of nerve damage in leprosy showing that nerve function impairment is more widespread than previously appreciated. Any nerve involvement, including sub-clinical changes, is predictive of further nerve function impairment. These new factors could be used to identify patients at high risk of developing impairment and disability.

Protein phosphorylation pattern in the immune cells of leprosy affected individuals.

BACKGROUND: Leprosy is an infectious disease in which the susceptibility to the pathogen Mycobacterium leprae and the clinical manifestations are attributed to host immune cell response. Receptor mediated events and signalling in the immune cells are mediated by protein phosphorylation. The main signalling pathways and protein kinases known to be involved in the regulation of immune cells are cAMP dependent kinases, calcium/calmodulin dependent kinases, protein kinase C and mitogen activated protein kinases. The cumulative consequence of alterations in signalling pathways can be evaluated by intrinsic cellular protein phosphorylation by gamma-P32 ATP. The present study was designed to assess the protein phosphorylation in the immune cells of leprosy patients as compared with normal individuals. METHODOLOGY: Lymphocyte protein phosphorylation was conducted in 15 leprosy patients and 9 normal individuals. Protein phosphorylation of lymphocytes was carried out in the presence/absence of protein kinase modulators. The phosphorylation patterns were documented and analysed consequent to SDS-PAGE, staining, destaining, drying and autoradiography. RESULTS: The major phosphorylated proteins in lymphocytes were of molecular weights 20-22, 24-29, 30-35, 43, 46-50 and 66-68 kDa. In general, the major phosphorylated proteins were similar in the controls and in the patients. The phosphorylatability of these proteins varied with different modulators. Variations in the phosphorylation pattern were observed in 25% of the leprosy patients where there was a decrease of the 66 kDa protein and a decrease of 20-22 kDa protein phosphorylation. CONCLUSION: The observed alterations in the protein phosphorylation pattern could be due to alteration in kinases and/or their substrates or due to the effect of M. leprae on immune cells.

Alteration of the cortisol-cortisone shuttle in leprosy type 1 reactions in leprosy patients in Hyderabad, India.

Regulation of inflammation in leprosy may be influenced by local concentrations of active cortisol and inactive cortisone, whose concentrations are regulated by enzymes in the cortisol-cortisone shuttle. We investigated the cortisol-cortisone shuttle enzymes in the skin of leprosy patients with type 1 reactions (T1R), which are characterised by skin and nerve inflammation. Gene expression of the shuttle enzymes were quantified in skin biopsies from 15 leprosy patients with new T1R before and during prednisolone treatment and compared with levels in skin biopsies from 10 borderline leprosy patients without reactions. Gene expression of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) type 2, which converts cortisol to cortisone, is down-regulated in skin from T1R lesions. However expression levels of 11beta-HSD type 1, which converts cortisone to cortisol, were similar in skin with and without reactions and did not change during anti-leprosy drug treatment. Prednisolone treatment of patients with reactions is associated with an upregulation of 11beta-HSD2 expression in skin. The down regulation of 11beta-HSD2 at the beginning of a reaction may be caused by pro-inflammatory cytokines in the leprosy reactional lesion and may be a local attempt to down-regulate inflammation. However in leprosy reactions this local response is insufficient and exogenous steroids are required to control inflammation.

Effects of prednisolone treatment on cytokine expression in patients with leprosy type 1 reactions.

Leprosy type 1 reactions (T1R) are due to increased cell-mediated immunity and result in localized tissue damage. The anti-inflammatory drug prednisolone is used for treatment, but there is little good in vivo data on the molecular actions of prednisolone. We investigated the effect of prednisolone treatment on tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-10, and transforming growth factor beta1 (TGF-beta1) mRNA and protein expression in blood and skin biopsies from 30 patients with T1R in India. After 1 month of prednisolone treatment the sizes of the skin granulomas were reduced, as were the grades of cells positive for TNF-alpha and IL-10 in skin lesions. Increased production of TGF-beta1 was seen in skin lesions after 6 months of prednisolone treatment. Expression of mRNA for TNF-alpha, IL-1beta, and TGF-beta1 was reduced, whereas no change in IL-10 mRNA expression was detected during treatment. The circulating cytokine profiles were similar in patients with and without T1R, and prednisolone treatment had no detectable effects on cytokine expression in the blood. The data emphasize the compartmentalization of pathology in T1R and the importance of the immune response in the skin. Clinical improvement and cytokine expression were compared. Surprisingly, patients with improved skin and nerve function and patients with nonimproved skin and nerve function had similar cytokine profiles, suggesting that clinical improvement is not directly mediated by the cytokines studied here. This in vivo well-controlled study of the immunosuppressive effects of prednisolone showed that the drug does not switch off cytokine responses effectively.

Diagnostic role of the antibody response to the 38kDa, 16kDa proteins and lipoarabinomannan of mycobacterium tuberculosis.

The antibody response to the 38kDa, 16kDa and Lipoarabinomannan (LAM) antigens ofMycobacterium tuberculosis was evaluated using three different ELISAs based on these antigens. The study group included tuberculosis patients (n=52), patients with HIV and TB co-infection (n=10), other chest symptomatics (n=5), HIV infected individuals (n=10), leprosy cases (n=7) and healthy controls (n=75). The results indicate that the 38kDa and LAM based ELISA for IgM/IgG has a low specificity (ranging from 69-85%) and sensitivity (ranging from 55-78%). When three ELISAs are carried out on a single patient the probability of detection of tuberculosis was significantly increased to 95.2% indicating that a single ELISA test is of low sensitivity and that a combination of ELISA's may be needed to be of any value as a diagnostic test for tuberculosis. Additionally, a western blot assay of the serum antibody response to protein fraction ofM. tuberculosis was analysed in 15 tuberculosis patients and five healthy controls. A multiple antibody response to various M.tuberculosis proteins was observed which varied from patient to patient as compared to controls who showed a single 38-39 kDa protein band positivity. These finding suggest that a western blot assay which determines the antibody response to a set of antigenic components ofM. tuberculosis could be a better serological test for the diagnosis of tuberculosis in our population.

Microsatellite mapping of Mycobacterium leprae populations in infected humans.

To investigate genetic diversity in a bacterial population, we measured the copy numbers of simple sequence repeats, or microsatellites, in Mycobacterium leprae from patients living in and around Hyderabad, India. Three microsatellite loci containing trinucleotide or dinucleotide repeats were amplified from infected tissues, and the copy numbers were established by sequence analysis. Extensive diversity was observed in a cross-sectional survey of 33 patients, but closely related profiles were found for members of a multicase family likely to share a common transmission source. Sampling of multiple tissues from single individuals demonstrated identical microsatellite profiles in the skin, nasal cavity, and bloodstream but revealed differences at one or more loci for M. leprae present in nerves. Microsatellite mapping of M. leprae represents a useful tool for tracking short transmission chains. Comparison of skin and nerve lesions suggests that the evolution of disease within an individual involves the expansion of multiple distinct subpopulations of M. leprae.

Microsatellite mapping of Mycobacterium leprae populations in infected humans

To investigate genetic diversity in a bacterial population, we measured the copy numbers of simple sequence repeats, or microsatellites, in Mycobacterium leprae from patients living in and around Hyderabad, India. Three microsatellite loci containing trinucleotide or dinucleotide repeats were amplified from infected tissues, and the copy numbers were established by sequence analysis. Extensive diversity was observed in a cross-sectional survey of 33 patients, but closely related profiles were found for members of a multicase family likely to share a common transmission source. Sampling of multiple tissues from single individuals demonstrated identical microsatellite profiles in the skin, nasal cavity, and bloodstream but revealed differences at one or more loci for M. leprae present in nerves. Microsatellite mapping of M. leprae represents a useful tool for tracking short transmission chains. Comparison of skin and nerve lesions suggests that the evolution of disease within an individual involves the expansion of multiple distinct subpopulations of M. leprae.