Cytokine polymorphisms not linked to VTE risk
MedWire News: Polymorphisms in genes encoding the inflammatory cytokines interleukin 6 (IL6), interleukin 8 (IL8), and monocyte chemotactic protein-1 (MCP-1) are not associated with risk for venous thromboembolism (VTE), Brazilian researchers report.
Increased levels of IL6 and IL8 themselves are, however, associated with increased VTE risk.
Vânia Morelli and colleagues from the Federal University of São Paulo explain that data concerning the role of cytokines in the risk for VTE are limited. Furthermore, differences in cytokine levels may be due, at least in part, to polymorphisms within the regulatory regions of cytokine genes.
The researchers therefore investigated whether the IL6 -174GC (rs1800795), IL8 -251AT (rs4073), and MCP-1 -2518AG (rs1024611) promoter polymorphisms - previously found to influence cytokine expression - affect thrombotic risk.
They collected blood from 119 patients (79% women) with a first event of VTE aged between 18 and 60 years, and 126 healthy age- and gender-matched controls. Blood collection took place at least one month after the discontinuation of oral anticoagulation, and more than 7 months after the thrombotic event.
The researchers report that IL6, IL8 and MCP-1 promoter polymorphism genotypes had no effect on the risk for VTE. In addition, none of the polymorphisms significantly influenced plasma levels of IL6, IL8, and MCP-1 in patients or controls.
However, after adjustment for age and gender, each 1 pg/mL increase in IL-6 and IL-8 was associated with significant 1.5- and 1.1-fold respective increases in the likelihood for thrombosis. By contrast, MCP-1 was not associated with an increased thrombosis risk.
The association between IL6 and thrombosis risk remained significant after further adjustment for ethnicity, body mass index, and high sensitive C-reactive protein, whereas that with IL8 was attenuated to borderline significance.
"Thus far, a causal relationship between inflammation and VTE remains to be clarified and more prospective data are warranted," the researchers conclude in the journal Thrombosis Research.
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By Laura Dean