Local immune response in skin of generalized vitiligo patients - Destruction of melanocytes is associated with the prominent presence of CLA(+) T cells at the perilesional site

In situ immune infiltrates in lesional, perilesional, and nonlesional skin biopsies from patients with vitiligo were analyzed by immunohistochemistry and compared with immune infiltrates found in the skin of normal healthy do nors and relevant disease controls. An increased influx of activated skin-h oming T cells and macrophages were seen in the perilesional biopsies. The o verall percentages of cutaneous leukocyte-associated antigen-positive (CLA( +)) T cells were similar to those found in normal healthy donors. This is c ompatible with the similar expression of E-selectin. Most strikingly, howev er, the CLA+ T cells in perilesional skin were mainly clustered in the vici nity of disappearing melanocytes, and 60% to 66% of these interacting T cel ls expressed perforin and granzyme-B. The perforin(+)/granzyme-B+ cells wer e not seen in locations different from that of disappearing melanocytes. in terestingly, the majority of the infiltrating T cells were HLA-DR/CD8(+). A nother hallmark of the present study is the focal expression of intercellul ar adhesion molecule(ICAM)-1 and HLA-DR in the epidermis at the site of int eraction between the immune infiltrates and the disappearing melanocytes. T he data presented in this study are consistent with a major role for skin-h oming T cells in the death of melanocytes seen in vitiligo.