[Is the psoriasis plaque test still relevant in the age of biologicals?].

A variety of approaches (in vitro-/ex vivo studies, animal models, human studies and clinical trials) are available to assess compounds with potential antipsoriatic properties. Over the past few years various rodent models that mirror aspects of psoriasis phenotypes and/or pathogenesis have been created (e. g. knockout rodents, xenotransplantation models). Unfortunately these animal models do not reflect the complete pathogenesis of psoriasis. Therefore, screening procedures involving psoriatic lesions in humans are necessary. Even in the era of biologicals, the psoriasis plaque test (PPT) remains an important in vivo tool. In addition to screening potential antipsoriatic substances, the PPT can help answer other questions (frequency of use, dose-response relationship). A prerequisite for correct performance of PPT is knowledge of the toxicological and pharmacological data of the investigational compounds. The PPT is relatively simple, not time-consuming and allows the simultaneous testing of multiple substance. All the results from PPT must be confirmed by controlled clinical trials.