Prothrombotic state and impaired fibrinolysis in bullous pemphigoid, the most frequent autoimmune blistering disease

Bullous pemphigoid (BP) is a potentially life-threatening autoimmune blistering disease that is burdened with an increased risk of cardiovascular events. In BP, there is an interplay between inflammation and coagulation both locally, which contributes to skin damage, and systemically, which leads to a prothrombotic state. Fibrinolysis is an important defence mechanism against thrombosis, but has only been studied locally in BP and no systemic data are available. The aim of this observational study was to evaluate systemic fibrinolysis and coagulation activation in patients with BP. We measured parameters of fibrinolysis and coagulation by immunoenzymatic methods in plasma from 20 patients with BP in an active phase and during remission after corticosteroid treatment. The controls were 20 age- and sex-matched healthy subjects. Plasma levels of plasminogen activator inhibitor type 1 (PAI-1) antigen, PAI-1 activity and tissue plasminogen activator (t-PA) antigen were significantly higher in the BP patients with active disease than in healthy controls (P=0·0001 for all), as were the plasma levels of the fibrin fragment d-dimer and prothrombin fragment F1+2 (P=0·0001 for both). During remission after treatment, levels of PAI-1 antigen and PAI-1 activity decreased significantly (P=0·008 and P=0·006, respectively), and there was also a significant decrease in plasma levels of d-dimer (P=0·0001) and F1+2 (P=0·0001). Fibrinolysis is inhibited in patients with active BP, due mainly to an increase in plasma levels of PAI-1. Corticosteroids not only induce the regression of BP lesions, but also reduce the inhibition of fibrinolysis, which may contribute to decreasing thrombotic risk. © 2012 British Society for Immunology.