Characterization of skin cytokines in bullous pemphigoid and pemphigus vulgaris

The purpose of this study was to determine cytokine and cell marker express ion in perilesional skin biopsies from patients with the autoimmune blister ing diseases bullous pemphigoid (BP, n = 21) and pemphigus vulgaris (PV, n = 7). Immunohistochemistry and in situ hybridization were used to detect T helper (Th)1 [interleulin (IL)-2, interferon (IFN)-gamma] and Th2 (IL-4, IL -5, IL-13) protein and mRNA. Perilesional skin biopsies from patients with BP were characterized by the deposition of IL-4, IL-13 and IL-5. In patient s with BP, IL-4 and IL-13 localized to mononuclear cells within the dermal infiltrate while IL-5 was predominately expressed at the dermal-epidermal j unction. BP skin sections also expressed vascular cell adhesion molecule 1 on endothelial cells, not seen in patients with PR PV biopsies were remarka ble for a mixed Th1/Th2 pattern of cytokine expression, including the prese nce of IL-2, IFN-gamma and IL-4 and the absence of IL-5 and IL-13. In situ hybridization detected mRNA for IL-4 and IL-5 in the cellular infiltrate of BP patients, and IL-2 In a patient with PV; In vitro binding assays demons trated that normal human eosinophils, activated by coculture in IL-5, bound preferentially to BP skin sections that contained detectable in vivo bound IL-5. The predominance of Th2 cytokines in BP, in association with increas ed binding of eosinophils in vitro, suggests that Th2 cytokines are relevan t in the recruitment and adhesion of eosinophils within the dermal infiltra tes of patients with BP, and may play a part in the pathogenesis of blister formation.