IN-SITU LABELING OF FRAGMENTED DNA IN CUTANEOUS NECROTIZING VASCULITIS

Apoptosis is a biochemically and morphologically gene-regulated distin ctive form of cell death playing a pivotal role in tissue homeostatis, viral infections and clearance of damaged cells. The process is initi ated by a cascade of intercellular and intracellular signals through a n intrinsic cell suicide program resulting in early DNA fragmentation characterized by nuclear and cytoplasmic condensation. Recently some a uthors have reported apoptosis to occur in several inflammatory skin d iseases, such as lichenoid reactions and cutaneous lymphomas. The aim of our study is to investigate the apoptotic phenomenon in two differe nt forms of cutaneous necrotizing vasculitis (CNV) affecting the postc apillary venules such as leukocytoclastic and lymphocytic cutaneous va sculitis. For this purpose, the in situ nick end labelling of fragment ed DNA technique has been performed on lesional skin biopsies from pat ients with acute phase of the disease. In both leukocytoclastic and ly mphocytic forms apoptotic bodies were detected, evidencing two differe nt characteristic patterns of distribution, probably related to the di fferent nature of cellular inflammatory infiltrate. Our results seem t o account for the involvement of apoptotic phenomena in cutaneous vasc ulitis; furthermore, the evaluation of in situ DNA fragmentation could be a useful tool to discriminate different forms of the disease. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.