Controlling the drug-resistant tuberculosis epidemic in India: challenges and implications / 한국역학회지

India has a higher tuberculosis (TB) burden than any other country, accounting for an estimated one-fourth of the global burden. Drug-resistant tuberculosis (DR-TB) presents a major public health problem in India. Patients with DR-TB often require profound changes in their drug regimens, which are invariably linked to poor treatment adherence and sub-optimal treatment outcomes compared to drug-sensitive TB. The challenge of addressing DR-TB is critical for India, as India contributes over 27% of global DR-TB cases. In recent decades, India has been proactive in its battle against TB, even implementing a revised National Strategic Plan to eliminate TB by 2025. However, to achieve this ambitious goal, the country will need to take a multifaceted approach with respect to its management of DR-TB. Despite concerted efforts made by the National TB Elimination Program, India faces substantial challenges with regard to DR-TB care, especially in peripheral and resource-limited endemic zones. This article describes some of the major challenges associated with mitigating the growing DR-TB epidemic in India and their implications.

Controlling the drug-resistant tuberculosis epidemic in India: challenges and implications / 한국역학회지

India has a higher tuberculosis (TB) burden than any other country, accounting for an estimated one-fourth of the global burden. Drug-resistant tuberculosis (DR-TB) presents a major public health problem in India. Patients with DR-TB often require profound changes in their drug regimens, which are invariably linked to poor treatment adherence and sub-optimal treatment outcomes compared to drug-sensitive TB. The challenge of addressing DR-TB is critical for India, as India contributes over 27% of global DR-TB cases. In recent decades, India has been proactive in its battle against TB, even implementing a revised National Strategic Plan to eliminate TB by 2025. However, to achieve this ambitious goal, the country will need to take a multifaceted approach with respect to its management of DR-TB. Despite concerted efforts made by the National TB Elimination Program, India faces substantial challenges with regard to DR-TB care, especially in peripheral and resource-limited endemic zones. This article describes some of the major challenges associated with mitigating the growing DR-TB epidemic in India and their implications.

Assessment of immunological markers and booster effects of Ag85B peptides, Ag85B, and BCG in blood of BCG vaccinated children: a preliminary report

PURPOSE: In the present study, the protective immunological markers in serum and peripheral blood mononuclear cells (PBMCs) of bacillus Calmette-Guerin (BCG) vaccinated and unvaccinated children were evaluated after vaccination. Further, PBMCs of children with low protective levels were boosted with BCG, Ag85B, and Ag85B peptides to study their booster effects to increase waning BCG induced immunity. MATERIALS AND METHODS: Fifty children from 1 month to 18 years of age were randomized for the study. Blood samples were collected from 27 participants with/without BCG vaccination. Immunological markers (anti-BCG, interferon gamma [IFN-gamma], and adenosine deaminase activity) were assessed in both serum and PBMCs of children. Children with low levels of protective immunological markers were further recruited and their PBMCs were boosted with BCG, Ag85B, and Ag85B peptides. RESULTS: Children in age group of 4-6 years were associated with significantly (p<0.05) higher BCG-specific IgG and IFN-gamma levels compared to those in age group greater than 10 years. Vaccinated children had greater repertoire of immunological memory which on in vitro stimulation with BCG showed increase in BCG-specific response compared to unvaccinated controls. Assessment of booster effects of BCG, Ag85B, and Ag85B peptides in PBMCs of children revealed greater potential of peptides to boost BCG induced immunity compared to BCG and Ag85B. CONCLUSION: To conclude, children within age 4-6 years are associated with high immunological markers which eventually diminish with age thereby suggesting need for booster dose in later years. Mycobacterium tuberculosis peptides along with BCG may be used as attractive candidates to boost such waning BCG induced immunity in children.

Comparative evaluation of booster efficacies of BCG, Ag85B, and Ag85B peptides based vaccines to boost BCG induced immunity in BALB/c mice: a pilot study

PURPOSE: In the present study booster efficacies of Ag85 B, Bacillus Calmette-Guerin (BCG), and Ag85B peptides were evaluated using prime boost regimes in BALB/c mice. MATERIALS AND METHODS: Mice were primed with BCG vaccine and subsequently boosted with Ag85B, BCG and cocktail of Ag85B peptides. RESULTS: Based on analysis of immune response it was observed mice boosted with Ag85B peptides showed significant (p < 0.001) cytokines levels (interferon gamma, interleukin 12) and BCG specific antibodies (anti-BCG and anti-purified protein derivative titre) compared to booster dose of BCG, Ag85B and BCG alone. CONCLUSION: Our pilot results suggest that prime boost regimes with Ag85B peptides can boost waning BCG induced immunity and may improve immunogenicity of BCG vaccine. However, lot of work is further needed using experimental model of tuberculosis infection to justify the result.

assessment of cytokines in quantiferon supernatants for the diagnosis of latent tb infection in a tribal population of Melghat, India

The tuberculin skin test [TST] and interferon-gamma release assays [IGRA], namely, the QuantiFERON-TB Gold test [QFT], remain the standard immuno-logical diagnostic tools for latent tuberculosis [TB] infection [LTBI]. However, the sub-optimal detection rates of both of these tests are major impediments in recognizing the population at risk. This study was aimed at evaluating additional cytokines besides interferon-gamma [IFN-gamma] as biomarkers for improving LTBI diagnosis in the tribal population of Melghat, India. Seventy-four close TB contacts were stratified by QFT and TST results into: [i] QFT+/TST+ [n = 26], [ii] QFT+/TST- [n = 12], [iii] QFT-/TST- [n = 35] and [iv] QFT-/TST+ [n = 1] groups. A panel of cytokines [IL-6, IL-10, TNF-alpha and IL-2R] was then evaluated in antigen-stimulated QFT cell-free culture supernatants using IMMULITE-1000, an automated immunoassay analyzer. Cytokine estimation showed significantly higher levels of IL-6 in the QFT+/TST+ group, while significantly higher levels of IL-10 were found in the QFT-/TST- group. Correlation analysis identified a positive correlation between IL-6 and the QFT response [r = 0.6723, P< 0.0001], while a negative correlation was seen between QFT and IL-10 expression [r=-0.3271, P = 0.0044]. Similarly, IL-6 was positively correlated with TST levels [r = 0.6631, P< 0.0001], and conversely, a negative correlation was found between TST and IL-10 expression [r=-0.5698, P<0.0001]. The positive and negative predictive values of IL-6 were found to be 92.59 and 93.33%, respectively, and the positive and negative predictive values of IL-10 were 96.55 and 91.18%, respectively. No significant impact of the demographic characteristics on cytokine positivity was observed. Our preliminary results suggest that the evaluation of additional cytokines in QFT cell-free culture supernatants may be valuable for the identification of LTBI. Combining IL-6 and IL-10 with QFT and/or TST could markedly improve the detection accuracy of LTBI. Our observations require investigation in larger well-characterized cohorts along with follow-up studies to further confirm the study outcome

Investigation of Immune Biomarkers Using Subcutaneous Model of M. tuberculosis Infection in BALB/c Mice: A Preliminary Report

Evaluation and screening of vaccines against tuberculosis depends on development of proper cost effective disease models along with identification of different immune markers that can be used as surrogate endpoints of protection in preclinical and clinical studies. The objective of the present study was therefore evaluation of subcutaneous model of M.tuberculosis infection along with investigation of different immune biomarkers of tuberculosis infection in BALB/c mice. Groups of mice were infected subcutaneously with two different doses : high (2x10(6) CFU) and low doses (2x10(2) CFU) of M.tuberculosis and immune markers including humoral and cellular markers were evaluated 30 days post M.tuberculosis infections. Based on results, we found that high dose of subcutaneous infection produced chronic disease with significant (p<0.001) production of immune markers of infection like IFNgamma, heat shock antigens (65, 71) and antibody titres against panel of M.tuberculosis antigens (ESAT-6, CFP-10, Ag85B, 45kDa, GroES, Hsp-16) all of which correlated with high bacterial burden in lungs and spleen. To conclude high dose of subcutaneous infection produces chronic TB infection in mice and can be used as convenient alternative to aerosol models in resource limited settings. Moreover assessment of immune markers namely mycobacterial antigens and antibodies can provide us valuable insights on modulation of immune response post infection. However further investigations along with optimization of study protocols are needed to justify the outcome of present study and establish such markers as surrogate endpoints of vaccine protection in preclinical and clinical studies in future.