Rapid Genotyping for Tumor Necrosis Factor-α (TNF-α) −863C/A Promoter Polymorphism That Determines TNF-α Response

Tumor necrosis factor-α (TNF-α) plays a central role in orchestrating the inflammatory response (1). Accordingly, blocking TNF-α activity has become a standard treatment of several inflammatory diseases (2)(3). TNF-α production shows high interindividual variations, which have been assigned mainly to inherited factors (4). Several genetic polymorphisms related to TNF-α synthesis have been detected in the TNF gene (5)(6). The −308 promoter polymorphism was found to affect TNF-α production by some authors (7) but not by others (8). Similar inconsistencies have been found for the association of this polymorphic site with susceptibility to and/or outcome of sepsis (8)(9). The Nco I polymorphism located within the first intron of the lymphotoxin A (LTA) gene was reported to be associated with TNF-α plasma concentrations (8). In a recent report, de Jong et al. (10) found no relationship between ex vivo TNF-α production on endotoxin stimulation of human whole blood and +489, −238, and −376 single-nucleotide polymorphisms or TNFa microsatellites of the TNF-α gene (10). Thus, the genetic factors determining the TNF-α response to infection are still poorly defined.Recently, Skoog et al. (11) identified a C/A exchange at position −863 of the TNF-α gene promoter and found higher transcriptional activity of the C allele in reporter gene assays. This polymorphic site was found to be associated with thyroid-associated ophthalmopathy (12), Crohn disease(13), juvenile rheumatoid arthritis (14), and the lumbar spine area (15).In the present study we sought to determine the association of the −863 TNF-α promoter polymorphism with the TNF-α production capacity of human blood cells. We describe a new real-time PCR assay with specific fluorescently labeled hybridization probes for genotyping for this polymorphism. We also genotyped samples for other polymorphic sites implicated in TNF-α production capacity and evaluated the possible existence of linkage …