Circulating levels of tissue factor microparticle procoagulant activity are reduced with antiretroviral therapy and are associated with persistent inflammation and coagulation activation among HIV-positive patients.

Activation of coagulation pathways may contribute to risk for non-AIDS-related conditions among HIV-positive patients. Tissue factor (TF)-dependent procoagulant activity on circulating microparticles (MP-TF) in the plasma of 163 HIV-positive participants, both untreated and treated, with viral suppression was measured. MP-TF activity was 39% lower among treated versus untreated participants (P < 0.001), which persisted in adjusted models (-36%, P = 0.03). Among treated participants, MP-TF activity correlated modestly with D-dimer (r = 0.24, P = 0.01), von Willebrand factor (r = 0.36, P < 0.001), and interleukin-6 (r = 0.20, P = 0.04) levels. Future research should focus on mechanisms driving residual functional TF activity and whether these alterations have clinical consequences for non-AIDS-defining complications.