Experimental induction and ultrastructural characterization of apoptosis in murine acute cutaneous graft-versus-host disease.
The skin is a primary target organ in acute graft-versus-host disease (GVHD). Recent results suggest that keratinocytes may undergo apoptosis in acute GVHD, although sequential structural evidence supporting this concept is lacking. The present study was undertaken to document and characterize apoptosis, confirmed by endonuclease-mediated DNA fragmentation, in experimental acute GVHD via sequential analysis of ultrastructure. Furthermore, we sought to define whether apoptosis is effector cell-dependent or- independent, and to document cell types responsible for the scavenging of apoptotic cells. Acute GVHD was produced across minor histocompatibility loci using appropriately matched murine strains and highly purified preparations of donor CD4+ and CD8+ T-cell subsets. Transmission electron microscopy was correlated with in situ labeling of double-stranded DNA breaks by the TUNEL (terminal uridine deoxynucleotidyl transferase end ligation) technique. Apoptotic cells were observed in all groups receiving T cells. Although most apoptotic cells were found in apposition with effector lymphocytes, a minority of apoptotic cells were detected at early time-points prior to lymphocytic infiltration. Heterogeneous cells, including macrophages, lymphocytes, Langerhans cells and keratinocytes were involved in scavenging putative target cells undergoing apoptosis. This study confirms the final pathway of target cell injury in acute GVHD to be apoptosis. In acute GVHD, apoptosis can be induced in the presence or absence of local effector cell influx, suggesting at least two mechanisms for the induction of epidermal target cell injury.
Yoo
Y H
YH
Department of Anatomy and Cell Biology, Dong-A University College of Medicine, Pusan, South Korea. yhyoo@seunghak.donga.ac.kr
Gilliam
A C
AC
Whitaker-Menezes
D
D
Korngold
R
R
Murphy
G F
GF
D000208:Acute Disease; D000818:Animals; D017209:Apoptosis; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism; D006086:Graft vs Host Disease / Q000473:pathology*; D015603:Keratinocytes / Q000648:ultrastructure; D051379:Mice; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D012871:Skin Diseases / Q000473:pathology*; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology
D004253:DNA Nucleotidylexotransferase