ISSN:
1365-3083
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
The genes for tumour necrosis factor alpha (TNFα) and lymphotoxin alpha (LTα; TNFβ) are tandemly arranged in the central region of the MHC. They may, therefore, be of importance for the aetiology of MHC-associated diseases. The authors have prospectively studied the secretion of TNFα and LTα in relation to polymorphisms at positions -308 and -238 in the TNFα gene (TNFA), and two polymorphisms in the first intron of the LTα gene (LTA), as well as HLA-DR in 30 patients with chronic inflammatory bowel diseases (IBD) and 12 healthy controls. In the Dutch population, the alleles of these four polymorphisms are present in only five combinations, called TNF-haplotypes: TNF-C, -E, -H, -I, and -P. Significant associations between TNF haplotypes and TNFα and LTα secretion were found when PBMC were cultured with T-cell activators, irrespective of disease. Mean TNFα secretion of individuals carrying the HLA-DR3 associated TNF-E haplotype was significantly higher, as compared to individuals without this haplotype (26 441 pg/ml versus 19 629 pg/ml; P = 0.014). Individuals carrying the TNF-C haplotype produced the lowest amount of TNFα (17 408 pg/ml; P = 0.022). The TNF-C and TNF-E haplotypes differ only at position -308 in the promoter of TNFA. Individuals carrying the HLA-DR1 associated TNF-I haplotype produced significantly less LTα when compared to those who lack this haplotype (1979 pg/ml versus 3462 pg/ml; P = 0.006). As the TNF-I haplotype is also associated with low TNFα secretion, this haplotype thus defines a ‘low secretor phenotype’. In conclusion, this is the first study to show associations between TNF haplotypes and TNFα and LTα secretion when T-cell stimulators are used. These findings will contribute to define disease heterogeneity in IBD and may be of relevance for understanding the pathogenesis of autoimmune diseases.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1365-3083.1996.d01-65.x
