Abstract: Objective To study the vascular endothelial damage and changes in parameters related to coagulation and anticoagulation function in patients with psoriasis, and to investigate their relationship to the development of psoriasis. Methods A total of 51 patients with psoriasis （29 at active stage and 22 at stable stage） were enrolled into this study, along with 50 normal controls. Twenty patients with active psoriasis received treatment with daily introvenous Danshen injection, topical triamcinolone acetonide cream as well as oral clarithromycin when necessary. Coagulation analyzer ACL 9000 was used to measure the parameters related to endothelial damage, coagulation and anticoagulation system in these patients and controls. Psoriasis area and severity index （PASI） was used to evaluate these patients before and after the treatment. The correlation between PASI and the tested parameters was assessed. Results Compared with the normal controls, decreased antithrombin activity as well as protein C activity and antigen were observed in patients at active stage ( 69.2％ ± 17.3％, 80.4％ ± 17.3％, 74.1％ ± 23.8％ respectively） and in those at stable stage （84.6％ ± 11.9％, 93.1％ ± 15.5％, 95.2％ ± 18.3％ respectively）, whereas increased levels of plasminogen activator inhibitor-1 and vW factor were found in active psoriatic patients （0.6 ± 0.5 Au/L, 100.7％ ± 25.6％ respectively） and in stable psoriatic patients （0.9 ± 0.6 Au/L, 141.6％ ± 59.1％ respectively）. Patients with active psoriasis had a higher level of vW factor but a lower level of antithrombin and protein C activity than those with stable psoriasis （all P < 0.01）. After treatment, the levels of antithrombin activity as well as protein C activity and antigen in patients with active psoriasis increased to 79.5％±13.0％, 87.6％ ± 10.9％, 86.9％ ± 20.5％ respectively, while the level of plasminogen activator inhibitor-1 and vW factor decreased to 1.0 ± 0.86 Au/L and 172.8％ ± 44.5％ respectively （all P < 0.01）. The activity of blood coagulation factor Ⅷ was lower in patients with stable psoriasis than in those with active psoriasis （129.4％ ± 33.2％ vs 156.2％ ± 67.1％, P < 0.01） but higher than in the normal controls （P < 0.01）. No significant difference was noticed in PASI before and after the treatment, and there was no correlation between PASI and any of the tested parameters. Conclusions There is an apparent damage to endothelial cells in psoriatic patients, which may lead to the attenuation of anticoagulation function and fibrinolysis activity. Also, the abnormality in anticoagulation and fibrinolysis system is closely related to the development of psoriasis.

Key words: psoriasis, coagulation system, anticoagulation system, endothelium