OBJECTIVETo investigate the immunologic reaction difference between xenogeneic and allogeneic acellular dermal matrix (ADM) grafting.

METHODSSplit thick skin samples harvested from healthy piglets and human volunteers who underwent losing-weight operation were processed to be xeno-ADM and allo-ADM. The ADMs overlapped with ultrathin auto-skin were employed to immediately cover the wound after escharectomy in deep burn patients. The patients were correspondingly set to be Xeno (26 cases) and Allo (10 cases) groups. Another 8 cases with deep burn wounds were grafted with only split thick autoskin (TTS) after escharectomy as control group. The tissue samples from grafted area were observed by immunohistochemistry after the grafting. The typing of immune cells in peripheral blood and grafted tissue was determined.

RESULTS(1) The CD4(+), CD45RO(+) and CD4(+)/CD8(+) cell ratios in peripheral blood in Xeno group increased slightly after the skin grafting when comparing to those in control group (P > 0.05). (2) There existed lasting inflammatory and immunological reaction in the local site of grafts in Xeno group. In addition, more than 80% of the inflammatory cells could be found to be CD3(+)/CD4(+), CD45RO(+). But CD8(+), Vs8C(+) plasmocytes and CD57(+) NK cells were found less. Furthermore, eosinophil and CD68(+)/CD4(+) foreign body megalocyte reactions could also be identified, especially in Xeno-ADM before rejection (P < 0.05 - 0.001). There was only mild inflammatory and immunological reaction during early grafting stage (within 8 post-operational weeks) in Allo-group.

CONCLUSIONThe specific immunologic reaction of human host to ADM might be participated by mononuclear cells and macrophages and presented mainly as cellular immune reaction induced by CD4(+) T lymphocytes. Furthermore, the foreign body megalocyte constructed by help T cell and macrophage might play important roles in the reaction.