Efficacy and Safety of Mycobacterium indicus pranii as an adjunct therapy in Category II pulmonary tuberculosis in a randomized trial.

Prolonged treatment of tuberculosis (TB) often leads to poor compliance, default and relapse, converting primary TB patients into category II TB (Cat IITB) cases, many of whom may convert to multi-drug resistant TB (MDR-TB). We have evaluated the immunotherapeutic potential of Mycobacterium indicus pranii (MIP) as an adjunct to Anti-Tubercular Treatment (ATT) in Cat II pulmonary TB (PTB) patients in a prospective, randomized, double blind, placebo controlled, multicentric clinical trial. 890 sputum smear positive Cat II PTB patients were randomized to receive either six intra-dermal injections (2 + 4) of heat-killed MIP at a dose of 5 × 108 bacilli or placebo once in 2 weeks for 2 months. Sputum smear and culture examinations were performed at different time points. MIP was safe with no adverse effects. While sputum smear conversion did not show any statistically significant difference, significantly higher number of patients (67.1%) in the MIP group achieved sputum culture conversion at fourth week compared to the placebo (57%) group (p = 0.0002), suggesting a role of MIP in clearance of the bacilli. Since live bacteria are the major contributors for sustained incidence of TB, the potential of MIP in clearance of the bacilli has far reaching implications in controlling the spread of the disease.

Treatment end point determinants for pulmonary tuberculosis: human resistin as a surrogate biomarker.

Treatment of tuberculosis (TB), which takes one human life every 15 s, globally, requires a prolonged (>6 months) antitubercular treatment (ATT) which, is known to have hepatotoxic side effects. This study was designed to explore the utility of human resistin, a proinflammatory hormone, as a sensitive biomarker to determine TB treatment end points. Patients for pulmonary tuberculosis enrolled under the directly observed treatment, short-course (DOTS) program were followed-up for six months and were monitored by sputum analysis, body weight and ELISA-based serum resistin and C-reactive protein (CRP) levels at 0, 2, 4 and 6 months, along with close family contacts of TB patients and healthy controls. The mean circulating resistin levels were found to be significantly higher (P < 0.001) in patients (n = 48, 25.74 ± 9.45 ng/ml) reporting for the first time for treatment (T0) as compared to healthy subjects (n = 45, 7.18 ± 2.40 ng/ml). Resistin levels in contacts (n = 48, 19.61 ± 7.88 ng/ml) also were found to be significantly (P < 0.001) elevated as compared to healthy controls. Significant increase in body weight after four months (P = 0.006) and at 6 months (P < 0.001) of treatment inversely correlated with resistin levels. Our data suggest resistin could be a surrogate marker for TB treatment in addition to its utility as an early prognostic biomarker for monitoring TB disease onset.

Association of strong immune responses to PPE protein Rv1168c with active tuberculosis.

Accurate diagnosis of tuberculosis (TB) infection is critical for the treatment, prevention, and control of TB. Conventional diagnostic tests based on purified protein derivative (PPD) do not achieve the required diagnostic sensitivity. Therefore, in this study, we have evaluated the immunogenic properties of Rv1168c, a member of the PPE family, in comparison with PPD, which is routinely used in the tuberculin test, and Hsp60 and ESAT-6, well-known immunodominant antigens of Mycobacterium tuberculosis. In a conventional enzyme immunoassay, the recombinant Rv1168c protein displayed stronger immunoreactivity against the sera obtained from patients with clinically active TB than did PPD, Hsp60, or ESAT-6 and could distinguish TB patients from Mycobacterium bovis BCG-vaccinated controls. Interestingly, Rv1168c antigen permits diagnosis of smear-negative pulmonary TB as well as extrapulmonary TB cases, which are often difficult to diagnose by conventional tests. The immunodominant nature of Rv1168c makes it a promising candidate to use in serodiagnosis of TB. In addition, our studies also show that Rv1168c is a potent T-cell antigen which elicits a strong gamma interferon response in sensitized peripheral blood mononuclear cells obtained from TB patients.

Regions of high antigenicity within the hypothetical PPE major polymorphic tandem repeat open-reading frame, Rv2608, show a differential humoral response and a low T cell response in various categories of patients with tuberculosis.

The function of the PE/PPE families of proteins, which represent approximately 10% of the coding capacity of the Mycobacterium tuberculosis genome, has remained relatively unknown. We earlier described a PPE family member, Rv2430c, as an immunodominant antigen. We now report another PPE family gene, Rv2608, a member of the major polymorphic tandem repeat subfamily, for its ability to elicit a high humoral and a low T cell response. Rv2608 was also found to be polymorphic in different clinical isolates of M. tuberculosis, as determined by polymerase chain reaction-restriction fragment-length polymorphism analysis. A total of 51 clinically confirmed patients with tuberculosis (TB), belonging to 3 different categories--fresh infection (n=22), relapsed infection (n=21), and extrapulmonary infection (n=8)--and 10 healthy control subjects were included in the study. Recombinant Rv2608 protein showed positive reactivity to patients' serum samples. Enzyme-linked immunosorbent assays and T cell-proliferation assays with synthetic peptides corresponding to predicted regions of high antigenicity showed a predominantly humoral response in patients with relapsed TB. We additionally identified the Gly-X-Gly-Asn-X-Gly repeat motifs as being primarily responsible for eliciting a humoral immune response.

Association of polymorphisms in the collagen region of human SP-A1 and SP-A2 genes with pulmonary tuberculosis in Indian population.

Surfactant protein A (SP-A) binds to and modulates phagocytosis of Mycobacterium tuberculosis by macrophages. We investigated the relationship between polymorphisms in the collagen regions of SP-A1 and SP-A2 genes and pulmonary tuberculosis. In the present study, seven single nucleotide polymorphisms (SNPs) (4 exonic and 3 intronic) have been identified in the collagen regions of SP-A1 and SP-A2 genes in Indian population. Two intronic polymorphisms, SP-A1C1416T ((p = 0.0000, odds ratio (OR) = 20.767,95% CI: 8.315-OR<51.870) and SP-A2C1382G (p = 0.0054; OR = 3.675, 95% CI: 1.400< OR<9.644), showed significant association with pulmonary tuberculosis (number of patients = 10, number of controls = 7). A redundant SNPA1660G of SP-A2gene showed significant association with pulmonary tuberculosis (number of patients = 17, number of controls = 19, p = 0.0000, OR = 8.94,95% CI: 3.311