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Obesity is a risk factor for asthma. Adipose tissue expresses pro-inflammatory molecules including tumour necrosis factor (TNF), and levels of TNF are also related to polymorphisms in the TNF-a (TNFA) gene. The current authors examined the joint effect of obesity and TNFA variability on asthma in adults by combining two population-based studies.The European Community Respiratory Health Survey and the Swiss Cohort Study on Air Pollution and Lung and Heart Disease in Adults used comparable protocols, questionnaires and measures of lung function and atopy. DNA samples from 9,167 participants were genotyped for TNFA -308 and lymphotoxin-a (LTA) +252 gene variants.Obesity and TNFA were associated with asthma when mutually adjusting for their independent effects (odds ratio (OR) for obesity 2.4, 95% confidence interval (CI) 1.7-3.2; OR for TNFA -308 polymorphism 1.3, 95% CI 1.1-1.6). The association of obesity with asthma was stronger for subjects carrying the G/A and A/A TNFA -308 genotypes compared with the more common G/G genotype, particularly among nonatopics (OR for G/A and A/A genotypes 6.1, 95% CI 2.5-14.4; OR for G/G genotype 1.7, 95% CI 0.8-3.3).The present findings provide, for the first time, evidence for a complex pattern of interaction between obesity, a pro-inflammatory genetic factor and asthma.

Genetic association studies have related the tumour necrosis factor-a gene (TNFA) guanine to adenine substitution of nucleotide -308 (-308G.A) polymorphism to increased risk of asthma, but results are inconsistent. The aim of the present study was to test whether two singlenucleotide polymorphisms, of TNFA and of the lymphotoxin-a gene (LTA), are associated with asthma, bronchial hyperresponsiveness and atopy in adults, by combining the results of two large population-based multicentric studies and conducting a meta-analysis of previously published studies.The European Community Respiratory Health Survey (ECRHS) and Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) used comparable protocols, including questionnaires for respiratory symptoms and measures of lung function and atopy. DNA samples from 11,136 participants were genotyped at TNFA -308 and LTA 252. Logistic regression employing fixed and random effects models and nonparametric techniques were used.The prevalence of asthma was 6%. The TNFA -308G.A polymorphism was associated with increased asthma prevalence and with bronchial hyperresponsiveness. No consistent association was found for atopy. The LTA 252A.G polymorphism was not associated with any of the outcomes. A meta-analysis of 17 studies showed an increased asthma risk for the TNFA -308 adenine allele.The tumour necrosis factor-a gene nucleotide -308 polymorphism is associated with a moderately increased risk of asthma and bronchial hyperresponsiveness, but not with atopy. These results are supported by a meta-analysis of previously published studies.

The DNA sequences imparting a maximal rate of sea urchin H2A gene transcription in the frog oocyte nucleus were narrowed down by deletion mapping to a DNA segment -165 to -111, far-upstream of the H2A mRNA cap site. C to T base changes in this area create strong down mutations, hence the primary structure of this DNA sequence is of paramount importance to the H2A gene expression. Sequence comparisons suggest that the -165 to -111 region may contain two essential sequence blocks. Most strikingly, the -135 area contains a 14 out of 17 basepair homology to the Moloney murine sarcoma virus enhancer and to topologically related 5' LTR-sequences of the simian sarcoma virus and the murine Friend spleen focus forming virus.