Association of SP-D, MBL and I-NOS genetic variants with pulmonary tuberculosis.

Background: Pulmonary tuberculosis is caused by Mycobacterium tuberculosis . It is a multifactorial disease with both host as well as pathogen factors contributing to susceptibility and protection from the disease. Various reports have highlighted important roles of lung surfactant protein D (SP-D), mannan-binding lectin (MBL) and I-NOS in innate immune defense against M. tuberculosis Aims : The present study investigated the role of polymorphisms in three candidate genes encoding Lung surfactant protein D, Mannan binding lectin and Inducible Nitric oxide synthase, in susceptibility and protection to pulmonary tuberculosis. Settings and Design : A case-control association study of SNP's in lung surfactant protein D (SP-D), mannan-binding lectin (MBL) and I-NOS with pulmonary tuberculosis in Indian population was carried out. This involved sequencing of all the coding exons of lung surfactant protein D (SP-D) , while, exon 1 (collagen region) and exon 4 (carbohydrate recognition domain) of mannan-binding lectin (MBL) and exons 2, 8 and 16 of I-NOS and their flanking intronic regions for single nucleotide polymorphisms in DNA samples isolated from 30 pulmonary tuberculosis patients and 30 controls of Indian population. Statistical analysis: Various allele frequencies were calculated using online two by two table (home.clara.net/sisa/). Odds ratio and P values were calculated at 95% confidence interval (CI). Results : A total of fourteen single nucleotide polymorphisms (5 in SP-D , 5 in MBL and 4 in I-NOS ) were observed of which four (G459A SP-D , G274T I-NOS , G1011A and T357G MBL ) have not been reported earlier. Four single nucleotide polymorphisms viz. G459A of exon 7 of SP-D ( P =0.00, odds ratio (OR) = 4.96, 2.18 P = 0.00 or= 3.85 1.66 P =0.00 or=4.04, 2.20< OR<7.42) and G274T of intron 16 of I-NOS ( P =0.00 or=4.46, 2.40 Conclusion: The present study has led to identification of 4 SNP's in SP-D , MBL and I-NOS associated with pulmonary tuberculosis in Indian population.

Post-BCG vaccination check based on serum IgG to culture filtrate antigens.

Since there are no reliable methods to demonstrate the effect of BCG vaccination in children, culture filtrates of BCG were evaluated for their specificity and sensitivity. BCG culture filtrate (BCG-CF), BCG sonicate and tuberculin were used as antigens and tested against serum, for the presence of IgG class of antibodies by ELISA and Western blot. Methodology: Children in the age-group of 1 to 10 years, were categorized as: (a) normal, and vaccinated, n=35; (b) normal, without a scar and with no evident history of vaccination, n=15; and (c) children with tuberculosis (meningitis, miliary and lymphadenitis) n=15. Results: The mean values of optical density (OD) in group (a), 4.0+0.08, were significantly high (P<0.001) to BCG-CF, compared to that of groups (b) (1.0+0.02) and (c) (1.4+0.03). The Western blot results revealed that a greater number of children (71%) in the vaccinated group reacted to low molecular weight proteins (10-30kDa) compared to other groups (unvaccinated: 17% and TB: 20%). The overall specificity, sensitivity, positive predictive value and negative predictive value of BCG-CF were higher in the vaccinated group. Conclusions: The results of the study suggest that the secreted antigens of BCG induce antibody formation, which are specific and are directed mostly towards the low molecular weight proteins. The presence of these antibodies could probably be exploited in an assay to distinguish children immunized by BCG from the unvaccinated and those having tuberculosis.

Tuberculin specific T cell responses in BCG vaccinated children.

The effector mechanisms of BCG protection were examined 5-7 years after vaccination. The in vitro lymphoproliferation, following stimulation with tuberculin, in normal, (A) vaccinated and (B) unvaccinated children and children with tuberculosis (C), were assayed. The mean stimulation index (SI) of lymphocyte transformation in normal subjects were significantly (P < 0.05) higher than those with tuberculosis. The ratio of tuberculin-specific CD4 to CD8 cells in short-term cultures were significantly (P less than 0.05) higher in the vaccinees. In group (A), 70 % had positive ratios as against 20 %and 0 %in groups (B) and (C), respectively. Secretion of IL-2 by the cells was significantly (P < 0.05) high in the vaccinated. None of the unvaccinated children had positive levels of IL-2. The vaccinees also had highly significant (P < 0.01) levels of IFN-)in the supernatants of cell-cultures, following tuberculin stimulation. In majority of the BCG vaccinated children, the stimulation of specific TH1 cells seem to be considerably high, in short-term in vitro cultures. While these responses were not so marked in the unvaccinated, they were almost totally absent in the patients.

Pulmonary function tests in Indian girls--prediction equations.

OBJECTIVE: The present study was conducted to evaluate pulmonary functions and develop prediction equations in Indian girls. METHODS: 1038 normal healthy schoolgirls in the age group of 5 to 15 years were selected for the present study. The anthropometrical parameters like height, weight, sitting height and chest circumference were measured and body surface area (BSA) and fat free mass (FFM) were derived using equations. The pulmonary functions such as FEV1, FVC, FEV1/FVC% and PEFR were studied. RESULTS: The height, sitting height, weight, BSA, chest circumference, body fat as well as FEV1, FVC, FEV1/FVC% and PEFR were comparable with Indian standards. Multiple regression equations were developed to predict FEV1, FVC and PEFR using anthropometrical indices like height, fat free mass and age or chest circumference in view of significantly high correlation of these parameters with lung function variables [height and FEV1 (r-0.90), height and FVC (r-0.899), height and PEFR (r-0.891), chest and FEV1 (r-0.868), chest and FVC (r-0.867), chest and PEFR (r-0.83)]. CONCLUSION: The regression equations to predict the pulmonary functions were presented using the independent variables like height, fat free mass and chest circumference or age, since these variables have shown very strong predictability for FEV1, FVC and PEFR. The equations presented in this study can be considered as referral standards for Indian girls.

Study on lung function tests and prediction equations in Indian male children.

OBJECTIVE: The present study was carried out to evaluate lung functions and develop prediction equations in Indian boys. SUBJECTS: 1555 normal healthy schoolboys from Hyderabad city who were in the age group of 5 to 15 years were selected for the present study. DESIGN: The anthropometric parameters such as height, sitting height, weight, and chest circumference were measured and body surface area (BSA) and percent body fat (% Fat) were derived. The lung functions studied were FEV1, FVC, FEV1% and PEFR. RESULTS: The height, sitting height, weight, BSA, chest circumference, body fat as well as FEV1, FVC, FEV1 % and PEFR were comparable with Indian boys. The height for age, weight for age and weight for height were found to be lower than 50th percentile of NCHS standards in the subjects studied. Similarly the lung function values of the study population were found to be lower than the values of corresponding western population. CONCLUSION: Regression equations were derived to predict FEV1, FVC and PEFR using physical characteristics. Height, chest circumference and fat free mass were the best predictors for FEV1, FVC, and PEFR. Age, height, sitting height, weight, chest circumference and fat free mass showed significant association with lung functions.