Tobacco use, tuberculosis and Covid-19: A lethal triad.

Smoking, TB and Covid-19 are high prevalence entities with public health consequences. All three of them have a possible complex interaction at cellular level. Smoking behavior makes it difficult to maintain infection control measures. Smoking is known to increase TB infection and also adversely affect treatment outcomes in TB. There is also upcoming evidence which suggests that smoking and TB increase the risk of severe Covid-19 symptoms. Simple infection control measures like, social distancing, cough etiquette, isolation, hand hygiene, quarantine, use of masks etc. play a pivotal role in prevention of these diseases. There is need of strengthening of the public health policies and incorporation of the Covid-19 safety awareness measures into the various national programmes.

Dr PK Sen TAI gold medal oration.

The current write-up is for Dr P.K.Sen TAI Gold Medal Oration Award for 2020 conferred to Dr Rupak Singla and delivered on 19 th December 2020. The title chosen for the oration was "Introduction and scale up of new anti-TB drugs in India: role of NITRD.Ë® However, in the oration the role this institute has played for overall scale up of Drug-resistant TB services in India under National Tuberculosis Elimination Programme (NTEP) at different times from the beginning of national TB programme has also been presented. National Institute of TB and Respiratory Diseases has travelled with our country from beginning of DR-TB care. It demonstrated for the first time use of a Standardized Treatment Regimen with second line drugs for MDR-TB in field conditions. NITRD assisted NTEP for the concept of DST guided treatment. This institute guided NTEP for the management of MDR-TB failure patients with Pre-XDR and XDR-TB. Also, NITRD assisted India for the introduction of newer DR-TB drugs and scale up of newer drugs across the country. The strength of NITRD include clinical expertise, laboratory support and training division. NITRD commitment is strong and will continue to support NTEP for all endeavors in future also.

Initial experience of bedaquiline implementation under the National TB Programme at NITRD, Delhi, India.

BACKGROUND: Bedaquiline (BDQ) was approved for treatment of drug resistant TB (DR-TB) under Conditional Access Programme (CAP) of Revised National Tuberculosis Control Programme (RNTCP) and was also implemented in the National Institute of TB and Respiratory Diseases (NITRD). We present early efficacy and safety of BDQ containing regimens for DR-TB. OBJECTIVE: To ascertain the early efficacy and safety of Bedaquline containing regimens in treatment of DR-TB. METHODS: BDQ containing regimens along with other drugs were designed as per WHO recommendations for DR-TB patients. They were followed up for sputum smear and culture conversion, adverse events during the treatment. RESULTS: A cohort of 290 DR-TB patients (Median age-29.77) were initiated on BDQ containing regimens. Of the available Sputum results, smear conversion was seen in 51% and 91% patients at the end of 1st week and 3rd month respectively. Similarly, 93% and 98% patients had culture conversion at the end of 3rd and 6th month respectively. 201 adverse events (AE) including 47 deaths were reported among 109 patients. QTc prolongation was seen in 29% patients but only 4 required discontinuation of BDQ. Lost to follow up of treatment was about 6%. CONCLUSION: Bedaquiline along with an optimized background regimen has shown early sputum conversion in larger number of difficult to treat patients having additional resistance of second line drugs along with INH and Rifampicin. The regimen is feasible in programmatic conditions and is relatively safe.

Recurrence of tuberculosis among newly diagnosed sputum positive pulmonary tuberculosis patients treated under the Revised National Tuberculosis Control Programme, India: A multi-centric prospective study.

INTRODUCTION: There is lack of information on the proportion of new smear-positive pulmonary tuberculosis (PTB) patients treated with a 6-month thrice-weekly regimen under Revised National Tuberculosis Control Programme (RNTCP) who develop recurrent TB after successful treatment outcome. OBJECTIVE: To estimate TB recurrence among newly diagnosed PTB patients who have successfully completed treatment and to document endogenous reactivation or re-infection. Risk factors for unfavourable outcomes to treatment and TB recurrence were determined. METHODOLOGY: Adult (aged ≥ 18 yrs) new smear positive PTB patients initiated on treatment under RNTCP were enrolled from sites in Tamil Nadu, Karnataka, Delhi, Maharashtra, Madhya Pradesh and Kerala. Those declared "treatment success" at the end of treatment were followed up with 2 sputum examinations each at 3, 6 and 12 months after treatment completion. MIRU-VNTR genotyping was done to identify endogenous re-activation or exogenous re-infection at TB recurrence. TB recurrence was expressed as rate per 100 person-years (with 95% confidence interval [95%CI]). Regression models were used to identify the risk factors for unfavourable response to treatment and TB recurrence. RESULTS: Of the1577 new smear positive PTB patients enrolled, 1565 were analysed. The overall cure rate was 77% (1207/1565) and treatment success was 77% (1210 /1565). The cure rate varied from 65% to 86%. There were 158 of 1210 patients who had TB recurrence after treatment success. The pooled TB recurrence estimate was 10.9% [95%CI: 0.2-21.6] and TB recurrence rate per 100 person-years was 12.7 [95% CI: 0.4-25]. TB recurrence per 100 person-years varied from 5.4 to 30.5. Endogenous reactivation was observed in 56 (93%) of 60 patients for whom genotyping was done. Male gender was associated with TB recurrence. CONCLUSION: A substantial proportion of new smear positive PTB patients successfully treated with 6 -month thrice-weekly regimen have TB recurrence under program settings.

Risk factors associated with development of pulmonary impairment after tuberculosis.

BACKGROUND: Treatment of pulmonary tuberculosis (PTB) focuses on microbiological cure and radiological improvement. However, many patients develop pulmonary impairment after the completion of anti-tubercular therapy (ATT), which affects their quality of life (QoL). AIM AND OBJECTIVE: To study the occurrence and severity of pulmonary impairment after tuberculosis (PIAT), risk factors associated with development of PIAT and QoL after development of PIAT. METHODOLOGY: 146 eligible PTB patients, who completed their ATT during January 2013 to December 2013 at National Institute of TB and Respiratory Diseases (NITRD), New Delhi and peripheral centres were enrolled after informed consent and evaluated. PIAT was graded using spirometric parameters. Severity of dyspnoea was assessed using Borg scale and Medical Research Council (MRC) scale. QoL was assessed using Seattle's Obstructive Lung Diseases Questionnaire (SOLDQ). RESULTS: 74% (108) had PIAT. On univariate analysis, smoking, education, body mass index (BMI), duration of illness prior to diagnosis of TB and number of prior ATT courses taken were the significant risk factors associated with the development of PIAT. On multiple logistic regression, patients who had taken ATT more than once was the independent risk factor associated with PIAT. Severity of dyspnoea was increased on both Borg scale and MRC scale with the increase in impairment of lung function. QoL was lower in patients with severe impairment. CONCLUSION: After bacteriological cure of TB after treatment, significant numbers of patients have poor lung function and poor QoL. There is need for prevention and management of such sequelae under national programme.

LipC (Rv0220) is an immunogenic cell surface esterase of Mycobacterium tuberculosis.

We have reported previously the identification of novel proteins of Mycobacterium tuberculosis by the immunoscreening of an expression library of M. tuberculosis genomic DNA with sera obtained from M. tuberculosis-infected rabbits at 5 weeks postinfection. In this study, we report the further characterization of one of these antigens, LipC (Rv0220). LipC is annotated as a member of the Lip family based on the presence of the consensus motif "GXSXG" characteristic of esterases. Although predicted to be a cytoplasmic enzyme, we provide evidence that LipC is a cell surface protein that is present in both the cell wall and the capsule of M. tuberculosis. Consistent with this localization, LipC elicits strong humoral immune responses in both HIV-negative (HIV-) and HIV-positive (HIV+) tuberculosis (TB) patients. The absence of anti-LipC antibodies in sera from purified protein derivative-positive (PPD+) healthy subjects confirms its expression only during active M. tuberculosis infection. Epitope mapping of LipC identified 6 immunodominant epitopes, 5 of which map to the exposed surface of the modeled LipC protein. The recombinant LipC (rLipC) protein also elicits proinflammatory cytokine and chemokine responses from macrophages and pulmonary epithelial cells. rLipC can hydrolyze short-chain esters with the carbon chain containing 2 to 10 carbon atoms. Together, these studies demonstrate that LipC is a novel cell surface-associated esterase of M. tuberculosis that is highly immunogenic and elicits both antibodies and cytokines/chemokines.

Use of urine volatile organic compounds to discriminate tuberculosis patients from healthy subjects.

Development of noninvasive methods for tuberculosis (TB) diagnosis, with the potential to be administered in field situations, remains as an unmet challenge. A wide array of molecules are present in urine and reflect the pathophysiological condition of a subject. With infection, an alteration in the molecular constituents is anticipated, characterization of which may form a basis for TB diagnosis. In the present study volatile organic compounds (VOCs) in human urine derived from TB patients and healthy controls were identified and quantified using headspace gas chromatography/mass spectrometry (GC/MS). We found significant (p < 0.05) increase in the abundance of o-xylene (6.37) and isopropyl acetate (2.07) and decreased level of 3-pentanol (0.59), dimethylstyrene (0.37), and cymol (0.42) in TB patients compared to controls. These markers could discriminate TB from healthy controls and related diseases like lung cancer and chronic obstructive pulmonary disorder. This study suggests a possibility of using urinary VOCs for the diagnosis of human TB.

Suppressors of cytokine signaling inhibit effector T cell responses during Mycobacterium tuberculosis infection.

Protective immune responses during Mycobacterium tuberculosis (M. tuberculosis) infection are regulated at multiple levels and critically dependent on the balance in the secretion of pro-inflammatory and regulatory cytokines. A key factor that governs this balance at the cellular level is suppressors of cytokine signaling (SOCS). We recently demonstrated that toll-like receptor 2 and dendritic cell (DC)-SIGNR1 differentially regulate SOCS1 expression in DCs during M. tuberculosis infection. This consecutively regulated IL-12 production and determined M. tuberculosis survival. In this study, we characterized the role of SOCS1 in regulating effector responses from CD4(+) and CD8(+) T cells during M. tuberculosis infection. Our data indicate that T cells from M. tuberculosis-infected mice show increased and differential association of SOCS1 with CD3 and CD28, when compared with uninfected mice. While SOCS1 displays increased association with CD3 than CD28 in CD4(+) T cells; SOCS1 is associated more with CD28 than CD3 in CD8(+) T cells. Further, SOCS1 shows increased association with IL-12 and IL-2 receptors in both CD4(+) and CD8(+) T cells from infected mice when compared with naive mice. Silencing SOCS1 in T cells increased signal transduction from T cell receptor (TCR) and CD28 with enhanced activation of key signaling molecules and proliferation. Significantly, SOCS1-silenced T cells mediated enhanced clearance of M. tuberculosis inside macrophages. Finally, adoptive transfer of SOCS1-silenced T cells in M. tuberculosis-infected mice mediated significant reduction in M. tuberculosis loads in spleen. These results exemplify the negative role played by SOCS1 during T cell priming and effector functions during M. tuberculosis infection.

Voltage gated calcium channels negatively regulate protective immunity to Mycobacterium tuberculosis.

Mycobacterium tuberculosis modulates levels and activity of key intracellular second messengers to evade protective immune responses. Calcium release from voltage gated calcium channels (VGCC) regulates immune responses to pathogens. In this study, we investigated the roles of VGCC in regulating protective immunity to mycobacteria in vitro and in vivo. Inhibiting L-type or R-type VGCC in dendritic cells (DCs) either using antibodies or by siRNA increased calcium influx in an inositol 1,4,5-phosphate and calcium release calcium activated channel dependent mechanism that resulted in increased expression of genes favoring pro-inflammatory responses. Further, VGCC-blocked DCs activated T cells that in turn mediated killing of M. tuberculosis inside macrophages. Likewise, inhibiting VGCC in infected macrophages and PBMCs induced calcium influx, upregulated the expression of pro-inflammatory genes and resulted in enhanced killing of intracellular M. tuberculosis. Importantly, compared to healthy controls, PBMCs of tuberculosis patients expressed higher levels of both VGCC, which were significantly reduced following chemotherapy. Finally, blocking VGCC in vivo in M. tuberculosis infected mice using specific antibodies increased intracellular calcium and significantly reduced bacterial loads. These results indicate that L-type and R-type VGCC play a negative role in M. tuberculosis infection by regulating calcium mobilization in cells that determine protective immunity.

Endobronchial tuberculosis presenting as tumorous mass.

We report a case of an 18-year-old boy presenting with features of right middle lobe collapse. On bronchoscopy, a tumorous type of endobronchial tuberculosis was found to be obstructing the lumen of the right middle lobe bronchus. On treatment with anti-tuberculous drugs the growth resolved significantly within three months. The patient, however, developed mild stenosis of the airway.

Influence of pre-treatment bacillary load on treatment outcome of pulmonary tuberculosis patients receiving DOTS under revised national tuberculosis control programme.

OBJECTIVE: To study the influence of initial bacillary load on sputum conversion rates and treatment outcome of new smear positive pulmonary tuberculosis patients. METHODS: A retrospective study was done among 2938 new smear positive pulmonary tuberculosis patients, registered at the peripheral centres, covering a population of 1.6 million in Delhi, India. The patients pre-treatment sputum smears were graded as 1+, 2+ or 3+ based on three samples. Patients were given intermittent short-course chemotherapy under supervision and the treatment outcome was analysed. RESULTS: Sputum conversion rates among patients graded as sputum 3+ and rest of the patients (combined graded sputum 1+ and 2+) at the end of two months were 62.2% and 76.8% respectively (p<0.001), and at the end of three months were 81.3% and 89.5% respectively (p<0.001). Cure rates among same group of patients were 76.6% and 85.1% respectively (p<0.001), and failure rates were 7.7% and 4.5% respectively (p<0.001). CONCLUSIONS: Under field conditions even with directly observed treatment (DOT) new smear positive patients with heavy bacillary load showed statistically significant poor sputum conversion rates at two and three months and higher failure rates as compared to patients with lesser bacillary load. To investigate possible reasons for this poor response and possible solutions further studies are needed.