A SNP upstream of the cyclic GMP-AMP synthase (cGAS) gene protects from relapse and extra-pulmonary TB and relates to BCG vaccination status in an Indian cohort.

Tuberculosis (TB) caused by Mycobacterium tuberculosis (M.tb) is a major health care threat worldwide causing over a million deaths annually. Host-pathogen interaction is complex, and a strong genetic contribution to disease susceptibility has been proposed. We have investigated single-nucleotide polymorphisms (SNPs) within cGAS/STING in Indian TB patients and healthy cohorts from India and Germany by Lightcycler®480 genotyping technique. The cGAS/STING pathway is an essential defense pathway within the cytosol after M.tb is internalized and mycobacterial DNA is released inducing the production of type I IFNs. We found that the rs311686 SNP upstream of cGAS provides protection from getting TB overall and is differently distributed in pulmonary TB patients compared with extra-pulmonary and particularly relapse cases. This SNP furthermore differs in distribution when comparing individuals with respect to BCG vaccination status. Taken together, our results show that the presence of the rs311686 SNP influences the course of TB significantly. However, structural conformation changes were found only for the cGAS rs610913 SNP. These findings underscore the importance of M.tb DNA recognition for TB pathogenesis and may eventually help in risk stratification of individuals. This may ultimately help in prevention of disease and aid in developing new vaccination and treatment strategies.

The Mycobacterium tuberculosis PPE protein Rv1168c induces stronger B cell response than Rv0256c in active TB patients.

Tuberculosis (TB) caused by Mycobacterium tuberculosis is a serious global health problem and is responsible for millions of deaths every year. For effective control of this dreadful disease, it is necessary to diagnose TB cases at the initial stages of infection. The serodiagnosis of disease represents simple, rapid and inexpensive method that can be used at the primary health care levels. In this study we have compared sensitivity of two PPE proteins of M. tuberculosis, i.e., Rv0256c and Rv1168c for their use as serodiagnostic markers in active tuberculosis patients. Employing a standardized enzyme immunoassay with these PPE proteins as candidate antigens we were able to successfully discriminate the TB patients' sera from the BCG-vaccinated healthy controls. Further, we observed that Rv1168c displayed higher sensitivity in detecting extrapulmonary and smear negative pulmonary TB cases which are difficult to diagnose by available diagnostic methods. Overall the study highlights that Rv1168c can be used as a potential serodiagnostic marker for the diagnosis of active tuberculosis disease.

Mycobacterium tuberculosis PPE protein Rv0256c induces strong B cell response in tuberculosis patients.

Tuberculosis (TB) is one of the most important diseases of humans and major public health problem worldwide. Early and accurate diagnosis of TB is necessary for the treatment, prevention, and control of TB. Therefore, it is important to identify suitable antigens that can differentiate active tuberculosis patients from BCG-vaccinated individuals. In the present study, we have used Rv0256c (PPE2) protein of Mycobacterium tuberculosis to screen the sera of infected patients belonging to different clinical TB presentations, and BCG-vaccinated clinically healthy individuals by enzyme immunoassay. Our results demonstrated that Rv0256c displayed stronger and specific immunoreactivity against the sera obtained from clinically active tuberculosis patients compared to PPD and ESAT-6 and could differentiate the TB-patients from the BCG-vaccinated controls. Importantly, Rv0256c was also found to detect even the extrapulmonary and smear-negative pulmonary cases which often are tedious and difficult to detect using conventional diagnostic methods. This study suggests that Rv0256c can be used as a potential marker for the serodiagnosis of tuberculosis patients.

Cytokine gene polymorphisms in the susceptibility to acute coronary syndrome.

AIM: Acute coronary syndrome (ACS) is an inflammatory disease. Cytokines are the central regulators of inflammation and may be a cause or marker of atherosclerosis. Accumulating evidence suggests that polymorphisms at promoter regions of various cytokine genes are known to be associated with their expression levels. In the present study we investigated whether variants at -1082G→A (rs1800896) and -592C→A (rs1800872) of interleukin-10 (IL-10), -1188A→C (rs3212227) of IL-12 p40, -308G→A of tumor necrosis factor-α (TNF-α) (rs1800629), -174G→C of IL-6 (rs1800795) and +874A→T of interferon-γ (IFN-γ) genes (rs2430561) are associated with ACS. MATERIALS AND METHODS: DNA samples were collected from 1083 subjects and IL-10-1082G→A, -592A→C, TNF-α-308G→A, IL-12 p40-1188 A→C, and IFN-γ+874A→T polymorphisms were identified by amplified refractory mutation system polymerase chain reaction and IL-6-174 G/C, restriction fragment length polymorphism based on standard methods. RESULTS: Six hundred and fifty one ACS patients along with 432 age and sex matched controls were analyzed for various gene polymorphisms. The "low-producer" IL-10-1082 AA (χ(2)=9.45; p=0.0021; odds ratio [OR]=1.472; 95% confidence interval [CI]=1.15-1.884), "high producer" IL-10-592 CC (χ(2)=39.42; p=0.001, OR=2.26; 95% CI=1.748-2.292), "low producer"IFN-γ+874AA (χ(2)=28; p<0.00154; OR=2.36 & 95% CI=1.713-3.251), and "high producer" TNF-α -308AA (χ(2)=3.213, p=0.073; OR=1.515) genotypes may be responsible for the regulation of immune response leading to inflammation in ACS patients. However, -1188 of the IL-12 gene was not associated with the disease. CONCLUSION: The polymorphisms at -308G→A of TNF-α, -174G→C of IL-6, +874A→T of IFN-γ and -1082G→A, and -592C→A of IL-10 genes evaluated in the present study are important risk factors for the development of ACS in the South Indian population from Andhra Pradesh. The better understanding of these variants conferring susceptibility to ACS may aid in early diagnosis and development of new methods to create personalized medicine.

In vitro levels of interleukin 10 (IL-10) and IL-12 in response to a recombinant 32-kilodalton antigen of Mycobacterium bovis BCG after treatment for tuberculosis.

Cell-mediated immunity plays a major role in conferring protection against tuberculosis (TB) on an individual. It is not known whether the immune status correlates with the bacterial load or whether the immunity improves after treatment. Also, it may be important to monitor treatment by being able to discriminate between active disease and successfully treated TB. The main aim of this study was to investigate the usefulness of a recombinant 32-kDa antigen (r32-kDa Ag) of Mycobacterium bovis BCG (Ag85A-BCG) as a diagnostic marker in patients being treated for TB. Specifically, the in vitro T-cell assays and the release of interleukin-12 (IL-12) (Th1-type cytokine) and IL-10 (Th2-type cytokine) in response to the r32-kDa Ag of BCG were assayed in patients with either pulmonary (sputum positive/negative, n = 74) or extrapulmonary TB (n = 49) and healthy controls. The proliferative responses of stimulated cells at 0, 2 to 4, and 6 months of treatment increased and were highly significant (P < 0.000) compared to the responses in controls. The increase in IL-12 and decrease in IL-10 release suggest that there is cytokine expression modification during different stages of TB, and treatment seems to have an influence on the levels of these cytokines, suggesting an augmentation in the protective responses. The in vitro response to the M. bovis BCG r32-kDa Ag may be useful in monitoring treatment of TB.