The C-reactive protein+1444C/T alteration modulates the inflammation and coagulation response in human endotoxemia

Background: C-reactive protein (CRP) plays a major role in the immune system and is an independent risk marker of cardiovascular disease. However, CRP's role in atherogenesis as innocent bystander, causative, or even protective agent, remains unresolved. The +1444C/T alteration in the CRP gene has been reported to determine basal CRP concentrations. We hypothesized that this alteration may also be associated with the degree of inflammatory response and coagulation activation in a well-standardized model of systemic inflammation. Methods: We administered 2 ng/kg endotoxin [Escherichia coli bacterial lipopolysaccharide (LPS)] intravenously to stimulate inflammation in 91 healthy young Caucasian male paid volunteers (age range, 19-40 years). Participants were confined to bed rest and fasted for 8.5 h after LPS infusion. We collected blood samples before LPS infusion and at 0, 2, 6, and 24 h after LPS infusion to measure inflammation markers [interleukin 6 (IL6), tumor necrosis factor-alpha (TNF alpha)], temperature, and coagulation markers (prothrombin fragment F1+2, D-dimer). We analyzed the CRP 3' untranslated variant with a mutagenic separated PCR assay. Results: Basal concentrations of high-sensitivity CRP were similar to 40% lower in +1444CC alteration carriers than in T homozygous (TT) allele carriers (P = 0.04). In contrast, basal IL6 concentrations were 2-fold higher in wild-type C homozygous (CC) than in TT individuals (P = 0.01). In response to the LPS challenge, CC individuals had 4-fold higher peak TNF alpha concentrations (P < 0.01), > 2.5-fold higher peak IL6 concentrations (P < 0.01), and increased temperature (P < 0.01). Twenty-four hours after LPS challenge, prothrombin fragment F1+2 concentrations were 75% higher and D-dimer concentrations 50% higher in CC than in TT individuals (P < 0.05). Conclusions: Genetic factors regulating CRP concentrations also modulate the individual response to endotoxin-stimulated inflammation. (c) 2006 American Association for Clinical Chemistry.