[Psoriasis vulgaris exacerbated by imatinib therapy in chronic myelogenous leukemia].

Administration of imatinib exacerbated psoriasis vulgaris in a case of chronic myelogenous leukemia (CML). After the cessation of imatinib therapy, the psoriasis was alleviated. Upon readministration of imatinib, the psoriasis worsened despite the improvement of hematological and cytogenetic findings in the CML. Psoriasis is known to be an autoimmune skin disease characterized by Th1 cell-mediated hyperproliferation of keratinocytes, and the type 1 helper T (Th1) cell subset increased with imatinib therapy. Thus, the exacerbation of psoriasis was likely due to the increase in Th1 cells associated with imatinib therapy.