V.S. Yadav

Serodiagnostic Efficacy of Mycobacterium tuberculosis 30/32-kDa Mycolyl Transferase Complex, ESAT-6, and CFP-10 in Patients with Active Tuberculosis

Elimination of tuberculosis (TB) largely depends upon definitive rapid diagnosis and treatment. Widely used diagnostic tests do not qualify for use in a developing country due to lack of either desired accuracy or their cost. In the present study an enzyme-linked immunosorbent assay was used to evaluate the diagnostic potential of an immuno-dominant 30/32-kDa mycolyl transferase complex (Ag85 complex) and Mycobacterium tuberculosis-specific proteins (ESAT-6 and CFP-10) of the RD1 region. Higher sensitivity (84.1%) with Ag85 complex was observed compared with ESAT-6 (64.9%) and CFP-10 (66%), with almost similar specificity (Ag85: 85.2%, ESAT-6: 88.9%, CFP-10: 85.2%), whereas the individual components of Ag85 complex, i.e. Ag85A, Ag85B, and Ag85C, showed sensitivities of 44.6, 34, and 80.9% and specificities of 55.6, 74.1, and 40.7% respectively. A cocktail of Ag85 complex, ESAT-6, CFP-10, Ag85A, Ag85B, and Ag85C antigens also could not help in increasing either sensitivity (51.1%) or specificity (85.2%). Furthermore, immunoblot analysis using clinical isolates as well as a standard strain (H37Rv) of M. tuberculosis also showed strong reactivity of sera from TB patients to Ag85 complex and, to a lesser extent, also to ESAT-6. To conclude, use of Ag85 complex along with ESAT-6 and CFP-10 seems to be promising in minimizing the heterogeneous sero-responses of adult TB cases.

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.

Cd4+, Cd8+, Cd3+ Cell Counts And Cd4+/cd8+ Ratio Among Patients With Mycobacterial Diseases (leprosy, Tuberculosis), Hiv Infections, And Normal Healthy Adults: A Comparative Analysis Of Studies In Different Regions Of India

In this study, we estimated the CD4+, CD8+, CD3+ cell counts and the CD4/CD8 ratio among normal healthy controls (adults and children), leprosy patients (without any complications and during reactional states), TB patients (with and without HIV), and HIV-positive patients (early infection and full-blown AIDS) and correlated the changes with disease progression. In our study, it was observed that among adults, CD4+ cell counts ranged from 518–1098, CD8+ from 312–952, whereas CD4/CD8 ratio from 0.75–2.30. Among children, both CD4+ and CD8+ cells were more and the CD4/CD8 ratio varied from 0.91–3.17. With regard to leprosy patients, we observed that CD4+ and CD8+ cell counts were lower among PB (pauci-bacillary) and MB (multi-bacillary) patients. CD4/CD8 ratio was 0.99 ± 0.28 among PB patients while the ratio was lower, 0.78 ± 0.20, among MB patients. CD4+ cell counts were raised during RR (reversal reactions) and ENL (erythema nodosum leprosum) among the PB and MB patients whereas the CD8+ cell counts were lower among PB and MB patients. CD4/CD8 ratio doubled during reactional episodes of RR and ENL. Among the HIV-negative tuberculosis (TB) patients, both the CD4+ and CD8+ cell counts were found to be less and the CD4/CD8 ratio varied between 0.53–1.75. Among the HIV-positive TB patients and HIV-positive patients, both the CD4+ and CD8+ cells were very less and ratio drops significantly. In the initial stages of infection, as CD4+ counts drop, an increase in the CD8+ cell counts was observed and the ratio declines. In full-blown cases, CD4+ cell counts were very low, 3–4 to 54 cells, CD8+ cells from 12–211 and the ratio drops too low. This study is the first of its kind in this region of the country and assumes importance since no other study has reported the values of CD4+ and CD8+ T-lymphocyte counts among patients with mycobacterial diseases (leprosy and TB), HIV infections along with normal healthy individuals of the region, and correlation with clinical presentations of patients.

Current status of Mycobacterium avium subspecies paratuberculosis infection in animals & humans in India: What needs to be done?

Mycobacterium avium subspecies paratuberculosis (MAP) has emerged as a major health problem for domestic livestock and human beings. Reduced per animal productivity of domestic livestock seriously impacts the economics of dairy farming globally. High to very high bioload of MAP in domestic livestock and also in the human population has been reported from north India. Presence of live MAP bacilli in commercial supplies of raw and pasteurized milk and milk products indicates its public health significance. MAP is not inactivated during pasteurization, therefore, entering into human food chain daily. Recovery of MAP from patients with inflammatory bowel disease or Crohns disease and animal healthcare workers suffering with chronic gastrointestinal problems indicate a close association of MAP with a number of chronic and other diseases affecting human health. Higher bioload of MAP in the animals increases the risk of exposure to the human population with MAP. This review summarizes the current status of MAP infection in animals as well as in human beings and also highlights the prospects of effective management and control of disease in animals to reduce the risk of exposure to human population.

National sample survey to assess the new case disease burden of leprosy in India

A national sample survey of leprosy was undertaken in partnership with Indian Council of Medical Research (ICMR) institutions, National Leprosy Eradication Programme (NLEP), Panchayati Raj members, and treated leprosy patients to detect new cases of leprosy in India. The objectives of the survey were to estimate the new leprosy case load; record both Grade 1 and Grade 2 disabilities in the new cases; and to assess the magnitude of stigma and discrimination prevalent in the society. A cluster based, cross-sectional survey involving all States was used for the door-to-door survey using inverse sampling methodology. Rural and urban clusters were sampled separately. The population screened for detecting 28 new cases in rural and 30 in urban clusters was enumerated, recorded and analyzed. Data capture and analysis in different schedules were the main tools used. For quality control three tiers of experts were utilized for the confirmation of cases and disabilities. Self-stigma was assessed in more than half of the total new patients detected with disabilities by the approved questionnaire. A different questionnaire was used to assess the stigma in the community. A population of 14,725,525 (10,302,443 rural; 4,423,082 urban) was screened and 2161 new cases - 1300 paucibacillary (PB) and 861 multibacillary (MB) were detected. New case estimates for leprosy was 330,346 (95% Confidence limits, 287,445-380,851). Disabilities observed in these cases were 2.05/100,000 population and 13.9 per cent (302/2161) in new cases. Self-stigma in patients with disabilities was reduced, and the patients were well accepted by the spouse, neighbour, at workplace and in social functions.

Differential Cytokine Response and IgG Subclasses in Pulmonary TB Patients,Household Contacts and BCG Vaccinated PPD-ve Healthy Controls

Immune response to Mycobacterium tuberculosis is complex and some cytokines are believed to be involved in protective response in humans. In the present study the levels of IFNγ, IL-17, IL-10 and IL-2 stimulated by PPD and ESAT-6 in the PBMCs of active untreated pulmonary TB patients (PTB), their PPD+ve household contacts (HHC) and PPD-ve healthy controls (H) has been estimated at the start and 2 months and 6 months after the start of treatment. IgG subclass antibodies to ESAT-6 and Ag85 complex circulating in the serum of the study subjects on the same days were also measured. Significantly elevated levels of cytokines were secreted by the unstimulated PBMC of patients and HHC in comparison to healthy individuals. PPD significantly increased the secretion of all the measured cytokines by the PBMC of healthy individuals and patients. Higher levels of IL-2 and lower levels of IL-10 were secreted by the PBMC of healthy individuals than the patients whereas that between HHC and patients did not differ. Ratio of IFNγ/IL-10 was also compared among study subjects and significantly higher ratio was observed in healthy subjects than patients and HHC. Significantly higher IgG1 response to ESAT-6 and Ag85 complex was detected in patients’ sera than HHC. No effect of treatment could be observed in cytokine and IgG1 levels in all the groups on all the days studied. Our findings suggest preactivated state of TB patients and their PPD+ household contacts and significant cellular immune reactivity by PPD-ve healthy individuals. Further, our findings suggest that IFNγ/IL-10 ratio could differentiate infection from cure.

Association of Toll like receptor 2 and 9 gene variants with pulmonary tuberculosis: exploration in a northern Indian population

Tuberculosis (TB) is a disease of global importance. There is an increasing recognition of the role of Toll like receptors, important pattern recognition receptors of host immune system, in determining the susceptibility or resistance to TB in various populations. In an attempt to examine the importance of Toll like receptors in immune response to Mycobacterium tuberculosis infection, we explored two variants each of TLR2 and TLR9 in a population residing in Uttar Pradesh, India. Genotyping was performed to detect -196 to -174 del polymorphism and G2258A SNP (Arg753Gln, rs5743708) in TLR2 gene and -T1237C (rs5743836) and G2848A (rs352140) SNP in TLR9 gene in patients with pulmonary TB and healthy controls. The A allele of G2848A SNP in TLR9 gene was found with a marginally higher frequency among TB patients as compared to healthy controls, suggesting that A allele at position 2848 of TLR9 gene may be associated with susceptibility to TB in North Indian population [p = 0.05, Mantel–Haenszel OR = 1.34, 95% CI (1.0–1.82)].

Human immunodeficiency virus and hepatitis B virus co-infections among tuberculosis patients attending a Model Rural Health Research Unit in Ghatampur, North India

Introduction: This prospective cross-sectional hospital-based study was carried out in order to assess the prevalence of human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infections among patients with active tuberculosis (TB) disease attending an Outpatient Department (OPD) at the Model Rural Health Research Unit in Ghatampur, a rural village in Kanpur district. Materials and Methods: The socio-demographic features and clinical profile of the TB patients were analysed in the context of symptoms at the time of testing. The HIV and HBV status were determined and correlated with clinical features at the time of testing. Results: In our study, the prevalence of HIV infection among TB patients is 1.48% (18/1215) and that of HBsAg reactivity was found to be 2.96% (36/1215). During 2007–2010, the HIV-positivity varied between 1.5% and 1.45% whereas HBV reactivity ranged between 2.4% and 3.63%.A substantial percentage of the TB patients attending the OPD in Ghatampur harbour HIV and HBV infections, which otherwise would remain undiagnosed without serological screening. Conclusion: Co infection with HBV among TB patients potentiate the risk of anti-tuberculous therapy-induced hepatotoxicity, therefore, exercising caution and carefully monitoring the patients for drugs associated hepatotoxicity is essential. There is an urgent need to perform population-based surveys of HIV and hepatitis infections among TB patients to assess the true extent of the problem. Efforts should be made to make physicians aware of the peculiarities and manage these patients effectively.