Cells of both epidermis and dermis constitutively express different Hsps, including Hsp90 [16], and some of them have been described to be upregulated in a variety of inflammatory skin conditions including UV-, hyperthermia- and heavy metal-provoked skin reactions [17]–[19], psoriasis [20], atopic dermatitis [21], systemic lupus erythematosus [22], lichen planus [23], Behçet’s disease [24], and graft-versus-host disease [25]. The gene discussed is HSP90AA1; the disease is graft versus host disease.