Plasma endothelin in psoriasis: possible relations to therapy and toxicity

Plasma endothelin levels were studied in 71 patients suffering from severe psoriasis. The psoriatics were treated either with topical therapy alone (n = 18) or with cyclosporin A (n = 26), methotrexate (n = 21), or with hydroxyurea, acitretin or ranitidin (n = 6) with or without topical therapy. The psoriatics had a significantly higher average plasma endothelin than 40 healthy controls. The patients treated with cyclosporin A had the highest values and these were in contrast to patients on methotrexate and other systemic therapy higher than patients treated with topical therapy alone. There was not significant difference between endothelin levels in patients treated with methotrexate compared to those in patients only receiving topical treatment. Whether the increased endothelin levels in plasma are derived from keratinocytes or enlarged vessels need to be investigated. An increased plasma endothelin level could be related to therapy and for patients on cyclosporin A be of importance for toxicity.