Racial differences in endotoxin‐induced tissue factor‐triggered coagulation

Background: Racial differences in coagulation are poorly understood. While some studies suggest a ‘prothrombotic’ coagulation profile in blacks compared with whites, others report an increased bleeding risk for blacks in various clinical settings. Moreover, preclinical data suggest a link between the Duffy antigen (= DARC, Duffy antigen receptor of chemokines) and coagulation. Objectives: Based on our previous research in Duffy antigen negative Africans, we hypothesized that Africans have an attenuated procoagulant response compared with Caucasians in a model of lipopolysaccharide (LPS)‐induced, tissue factor (TF)‐triggered coagulation activation. Patients/methods: Healthy male volunteers (16 Duffy‐negative Africans, 16 Duffy‐positive Caucasians) received 2 ng kg−1 LPS, and outcome parameters were measured using enzyme immunoassays and real‐time polymerase chain reaction (RT‐PCR, Taqman). Results: LPS increased microparticle (MP)‐associated TF procoagulant activity (PCA) less in Africans than Caucasians. Africans had reduced in vivo thrombin formation compared with Caucasians: they generated less thrombin–antithrombin (TAT) complexes (10.4 pg mL−1 vs. 23.0 pg mL−1, P