Interleukin-6 and interleukin-6 promoter polymorphism (-174) G > C in patients with spontaneous venous thromboembolism.

Increased levels of interleukin-6 (IL-6) have been reported in patients with a history of venous thromboembolism (VTE); however, prospective studies did not confirm an association between inflammatory markers that are highly correlated with IL-6 and the risk ofVTE. It was the aim of our study to investigate the association of IL-6 and its promoter polymorphism (-174) G > C with the risk of spontaneousVTE. IL-6 was measured in 128 patients with deep venous thrombosis (DVT,70 w/58 m),105 with pulmonary embolism (PE, 58 w/47 m) and 122 healthy controls (60 w/62 m) with a highly sensitive ELISA (Quantikine HS Human IL-6 Immunoassay, RnDSystems). The promoter polymorphism was determined by genotyping, allele specific PCR was followed by high resolution gel-electrophoresis. Median concentrations [interquartile ranges] were 2.37 [1.51-3.89] (pg/ml) in patients with DVT, 2.83 [1.83-4.87] in those with PE and 2.51 [1.71-4.78] in controls (p = 0.6, p = 0.4). Hetero- or homozygous carriers of the C allele (71% in DVT, 67% in PE and 59% among controls) did not have higher IL-6 levels than homozygous carriers of the G allele (median 2.60 vs. 2.59 pg/ml, p = 0.7). In conclusion, we found no association of IL-6 and its promoter polymorphism (-174) G > C with the risk of spontaneous VTE.