P7.72 THE PROGRESSIVE ALOPECIA AREATA DISEASE STATE AND THERAPEUTIC RESPONSE TOWARDS A CONTACT SENSITIZER ARE REFLECTED IN PERIPHERAL BLOOD MONONUCLEAR CELLS

Kevin J. McElwee, Pia Freyschmidt-Paul, Margot Zöller*, Mario Vitacolonna*, and Rolf Hoffmann

Department of Dermatology, Philipp University Marburg, Marburg, *Department of Tumor Progression and Tumor Defense, German Cancer Research Center, Heidelberg, Germany

Objectives: Alopecia areata (AA) is a putative autoimmune disease of the skin with an inflammatory component that can be treated by local application of contact sensitizers. Here we explored whether responsiveness towards diphenylcyclopropenone (DPCP) is reflected by the composition and the activation state of peripheral blood mononuclear cells (PBMC). PBMC of 43 AA patients, 26 treated and 17 untreated, and of 31 healthy volunteers were tested.

Results: AA patients’ PBMC differed from healthy donors’ PBMC by a slight increase in CD16 and TNF_alpha expressing cells. These features were independent of the disease state and treatment. Additional changes in the activation state of PBMC, upregulation of the co-stimulatory molecules CD40 and CD80, of the accessory molecule CD154 and of IFN_gamma expression, were identified only in AA patients where the disease was advancing, i.e. these changes were independent of the extent of hair loss and were not seen in patients with spontaneous or DPCP-treatment-induced, regressing AA.

Conclusions: The progressive state of AA is accompanied by a systemic activation of T cells and the therapeutic efficacy of treatment can be estimated by restoration of the non-activated state. Furthermore, an increase in CD16⁺ (candidate NK cell phenotype) and TNF_alpha expressing cells may contribute to AA susceptibility.