Low serum vitamin D in North Indian multi-drug resistant pulmonary tuberculosis patients: the role of diet and sunlight.

Background: Tuberculosis (TB) and malnutrition are major global health problems, with multidrug-resistant (MDR) TB complicating international efforts. The role of vitamin D in susceptibility to and as an adjunctive treatment for TB is being studied extensively, although no study has included MDR-TB patients in context to dietary profile with vitamin D levels and sunlight exposure.Objective: This study aimed to estimate vitamin D serum levels and examine their association with dietary intake of vitamin D and sun exposure in patients with MDR-TB.Methods: North Indian participants were enrolled in three groups: MDR-TB, drug-susceptible pulmonary TB (DS-PTB), and healthy controls. All consenting participants underwent the estimation of macro- and micronutrient intake and sunlight exposure using structured questionnaires. Serum biochemistry, including 25-hydroxyvitamin D and calcium levels, was measured, and the correlation between variables was determined.Results: 747 participants were enrolled. Significant differences among the three groups were found in mean serum 25-hydroxyvitamin D levels, body mass index, macronutrient intake, dietary vitamin D and calcium content, and sun exposure index (SEI). All except sun exposure (SEI was highest in DS-PTB patients) were found to follow the trend: MDR-TB < DS-PTB < healthy controls. The mean serum vitamin D levels of all groups were deficient and correlated positively with dietary intake and SEI.Conclusion: In this study's we found significant association of serum vitamin D concentrations, dietary intake and sunlight exposure in MDR-TB, DS-PTB patients and healthy controls. Dietary intake may be more important than sun exposure in determining serum levels. However, the significance of this finding is uncertain. Further studies are required to confirm the association, direction, and potential for vitamin D supplementation to treat or prevent MDR-TB infection.

Establishment of Elevated Serum Levels of IL-10, IL-8 and TNF-ß as Potential Peripheral Blood Biomarkers in Tubercular Lymphadenitis: A Prospective Observational Cohort Study.

BACKGROUND: Tubercular lymphadenitis (TL) is the most common form of extra-pulmonary tuberculosis (TB) consisting about 15-20% of all TB cases. The currently available diagnostic modalities for (TL), are invasive and involve a high index of suspicion, having limited accuracy. We hypothesized that TL would have a distinct cytokine signature that would distinguish it from pulmonary TB (PTB), peripheral tubercular lymphadenopathy (LNTB), healthy controls (HC), other lymphadenopathies (LAP) and cancerous LAP. To assess this twelve cytokines (Tumor Necrosis Factor (TNF)-α, Interferon (IFN) -γ, Interleukin (IL)-2, IL-12, IL-18, IL-1ß, IL-10, IL-6, IL-4, IL-1Receptor antagonist (IL-1Ra), IL-8 and TNF-ß, which have a role in pathogenesis of tuberculosis, were tested as potential peripheral blood biomarkers to aid the diagnosis of TL when routine investigations prove to be of limited value. METHODS AND FINDINGS: A prospective observational cohort study carried out during 2010-2013. This was a multi-center study with three participating hospitals in Delhi, India where through random sampling cohorts were established. The subjects were above 15 years of age, HIV-negative with no predisposing ailments to TB (n = 338). The discovery cohort (n = 218) had LNTB (n = 50), PTB (n = 84) and HC (n = 84). The independent validation cohort (n = 120) composed of patients with cancerous LAP (n = 35), other LAP (n = 20) as well as with independent PTB (n = 30), LNTB (n = 15) and HC (n = 20). Eight out of twelve cytokines achieved statistical relevance upon evaluation by pairwise and ROC analysis. Further, variable selection using random forest backward elimination revealed six serum biosignatures including IL-12, IL-4, IL-6, IL-10, IL-8 and TNF-ß as optimal for classifying the LNTB status of an individual. For the sake of clinical applicability we further selected a three analyte panel (IL-8, IL-10 and TNF-ß) which was subjected to multinomial modeling in the independent validation cohort which was randomised into training and test cohorts, achieving an overwhelming 95.9% overall classifying accuracy for correctly classifying LNTB cases with a minimal (7%) misclassification error rate in the test cohort. CONCLUSIONS: In our study, a three analyte serum biosignatures and probability equations were established which can guide the physician in their clinical decision making and step wise management of LNTB patients. This set of biomarkers has the potential to be a valuable adjunct to the diagnosis of TL in cases where AFB positivity and granulomatous findings elude the clinician.

Comparison of spoligotyping, mycobacterial interspersed repetitive units typing and IS6110-RFLP in a study of genotypic diversity of Mycobacterium tuberculosis in Delhi, North India.

The aim of the present study was to compare polymerase chain reaction (PCR)-based methods--spoligotyping and mycobacterial interspersed repetitive units (MIRU) typing--with the gold-standard IS6110 restriction fragment length polymorphism (RFLP) analysis in 101 isolates of Mycobacterium tuberculosis to determine the genetic diversity of M. tuberculosis clinical isolates from Delhi, North India. Spoligotyping resulted in 49 patterns (14 clusters); the largest cluster was composed of Spoligotype International Types (SITs)26 [Central-Asian (CAS)1-Delhi lineage], followed by SIT11 [East-African-Indian (EAI) 3-Indian lineage]. A large number of isolates (75%) belonged to genotypic lineages, such as CAS, EAI and Manu, with a high specificity for the Indian subcontinent, emphasising the complex diversity of the phylogenetically coherent M. tuberculosis in North India. MIRU typing, using 11 discriminatory loci, was able to distinguish between all but two strains based on individual patterns. IS6110-RFLP analysis (n = 80 strains) resulted in 67 unique isolates and four clusters containing 13 strains. MIRUs discriminated all 13 strains, whereas spoligotyping discriminated 11 strains. Our results validate the use of PCR-based molecular typing of M. tuberculosis using repetitive elements in Indian isolates and demonstrate the usefulness of MIRUs for discriminating low-IS6110-copy isolates, which accounted for more than one-fifth of the strains in the present study.

Comparison of spoligotyping, mycobacterial interspersed repetitive units typing and IS6110-RFLP in a study of genotypic diversity of Mycobacterium tuberculosis in Delhi, North India

The aim of the present study was to compare polymerase chain reaction (PCR)-based methods - spoligotyping and mycobacterial interspersed repetitive units (MIRU) typing - with the gold-standard IS6110 restriction fragment length polymorphism (RFLP) analysis in 101 isolates of Mycobacterium tuberculosis to determine the genetic diversity of M. tuberculosis clinical isolates from Delhi, North India. Spoligotyping resulted in 49 patterns (14 clusters); the largest cluster was composed of Spoligotype International Types (SITs)26 [Central-Asian (CAS)1-Delhi lineage], followed by SIT11 [East-African-Indian (EAI) 3-Indian lineage]. A large number of isolates (75 percent) belonged to genotypic lineages, such as CAS, EAI and Manu, with a high specificity for the Indian subcontinent, emphasising the complex diversity of the phylogenetically coherent M. tuberculosis in North India. MIRU typing, using 11 discriminatory loci, was able to distinguish between all but two strains based on individual patterns. IS6110-RFLP analysis (n = 80 strains) resulted in 67 unique isolates and four clusters containing 13 strains. MIRUs discriminated all 13 strains, whereas spoligotyping discriminated 11 strains. Our results validate the use of PCR-based molecular typing of M. tuberculosis using repetitive elements in Indian isolates and demonstrate the usefulness of MIRUs for discriminating low-IS6110-copy isolates, which accounted for more than one-fifth of the strains in the present study.

Differential serum cytokine levels are associated with cytokine gene polymorphisms in north Indians with active pulmonary tuberculosis.

Globally only 5-10% of people encountering Mycobacterium tuberculosis have a lifetime risk of active disease indicating a strong host genetic bias towards development of tuberculosis. In the current study we investigated genotype variants pertaining to five cytokine genes namely IFNG, TNFA, IL4, IL10 and IL12 in the north Indian population with active pulmonary tuberculosis (APTB) and correlated the serum cytokine levels with the corresponding genotypes. Twenty five single nucleotide polymorphisms (SNPs) including six loci examined for the first time in tuberculosis were selected for genotyping in 108 patients with APTB from north India and 48 healthy regional controls (HC). Applying exclusion criteria 12 SNPs passed all the filters and were analysed further. The serum cytokine concentrations were measured by ELISA. Compared to HC mean serum IFN-γ, IL-12, IL-4, and IL-10 levels were higher in APTB (p = 0.3661, p = 0.0186, p = 0.003, p = 0.7, respectively). In contrast the mean serum TNF-α level was higher in HC (p = 0.007). Comparison of genotypes and serum levels of the corresponding cytokine genes reveal that though IFN-γ and IL-4 levels were higher in APTB the genotype variants showed no difference between HC and APTB. In contrast the genotypes of the selected rsIDs in the TNFA, IL12 and IL10 genes showed significant association with the varying serum levels of corresponding cytokines. The variant of the TNFA gene at rs3093662, the IL12 gene at rs3213094 and rs3212220 and the IL10 gene at rs3024498 did show a strong indication to be of relevance to the immunity to tuberculosis. To our knowledge this is the first report from this region relating genotypes and serum cytokine levels in north Indian population.

Drug resistance among Mycobacterium tuberculosis isolates from private clinics and a dots center in Delhi, India.

The aim of this study was to ascertain the incidence of drug resistance of Mycobacterium tuberculosis isolates from patients in Delhi, India, being treated with DOTS and in private clinics, since a large proportion of patients with tuberculosis in India seek help from private healthcare sectors. Sputum samples were collected from 60 cases of tuberculosis attending a DOTS center and 42 patients from private clinics. Of these, 35 patients from the DOTS center and 12 patients from private clinics had a second sputum sample collected following two months of therapy. The isolated M. tuberculosis strains were assayed for isoniazid (INH), rifampicin (RIF), streptomycin (SM) and ethambutol (EMB) susceptibility by the proportion method. The frequencies of multidrug resistance (MDR) in the M. tuberculosis strains obtained from those treated with DOTS and in private centers were 12.7% and 5% (p > 0.5), respectively. Isolates obtained after two months of therapy showed a similar rate of MDR (12.5%) at the DOTS center, although the number of patients followed-up at the private centers was small, none of these had MDR after two months of therapy. Future studies including a larger number of patients at private centers are needed to further evaluate the prevalence of drug resistance in M. tuberculosis from private clinics.

Large-scale validation of a latex agglutination test for diagnosis of tuberculosis.

Large-scale validation of a simple latex agglutination test for the diagnosis of tuberculosis is described. Soluble antigens extracted from a non-pathogenic saprophytic mycobacterium, Mycobacterium w, which shares antigenic determinants with Mycobacterium tuberculosis, were covalently linked to carboxylated polystyrene latex beads. Batch to batch reproducibility of coated latex was ensured. Latex reagents were standardized to overcome non-specific agglutination. Reagents of the test are stable for 1 year at 4 degrees C. A total of 1,058 serum samples of pulmonary and extrapulmonary tuberculosis patients or patients with other pulmonary diseases and healthy controls living in endemic areas were tested. Sensitivity of 94% for pulmonary tuberculosis and 87% for extrapulmonary tuberculosis was obtained. Specificity is 92.2% for healthy controls and patients with other respiratory diseases. We conclude that the latex agglutination test can be utilized for mass screening for both pulmonary and extrapulmonary tuberculosis where diagnosis by existing methods is much more difficult.