['Satellite cell necrosis is a histopathologic hallmark of cutaneous graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation. Although this interaction of lymphocytes with keratinocytes has features of immune cytolytic destruction, the details of the process are not known.', 'Our purpose was to investigate whether apoptosis is involved in the process of GVHD.', 'We used TdT-mediated dUTP-biotin nick end labeling (TUNEL) technique with biotinylated nucleotides. Formalin-fixed, paraffin-embedded sections from skin biopsy specimens of patients with GVHD and normal skin were studied.', 'Labeling of scattered individual keratinocytes in the epidermis and adnexal epithelium undergoing cytolytic degeneration and a proportion of the adjacent lymphocytes was noted in all specimens of GVHD.'] Is apoptosis the mode of keratinocyte death in cutaneous graft-versus-host disease?