The effect of adalimumab on the vasculature in psoriatic skin lesions.

Background: Vascular proliferation is considered an important feature in psoriasis. Early psoriatic changes are characterized by vascular network expansion; healing of the lesions ultimately results in a decreasing size of the vascular network. Currently, the response of the vasculature in psoriatic lesions during treatment of adalimumab is still obscure.

Objective: To investigate the response of the vasculature in psoriatic lesions during adalimumab treatment, using parameters such as endothelial cell proliferation, vascular network size and alternations in vessel diameter.

Methods: The endothelial cell response (endothelial cell proliferation rate, vascular network size and vessel diameter) was studied, using an immunohistochemical double-staining of Ki67/CD31, in subsequent biopsies of psoriatic lesions from 10 patients treated with adalimumab at baseline, 10 days and 16 weeks after initiation of treatment.

Results: In active psoriatic skin the endothelial cell proliferation ratio is high and an increased vascular network size and vessel diameter is found. An evident decrease in all these parameters is found during 16 weeks treatment with adalimumab. Keratinocyte proliferation already decreased significantly and substantially after 10 days treatment.

Discussion: Adalimumab treatment of psoriasis causes an evident reduction in endothelial cell proliferation, vascular network size and vessel diameter, parallel to the clinical improvement. Vascular parameters do not capture early improvement to adalimumab treatment, however (non-)invasive measurement of vascular function parallels, the clinical improvement and may be a valuable marker for disease activity.