Difference in the expression of Fas/Fas-ligand and the lymphocyte subset reconstitution according to the occurrence of acute GVHD

Abstract

Acute graft-versus-host disease (aGVHD) remains a major barrier to a wider application of allogeneic bone marrow transplantation (BMT). Although this complication is mainly dependent on donor-derived T lymphocytes, very little information is available concerning the mechanism of lethality. In this study, we investigated both the expression of Fas/Fas-ligand (FasL) and lymphocyte subset reconstitution in patients who underwent HLA-matched related allogeneic BMT (n = 16) and normal donors (n = 10), and several distinct features were observed. First, the reconstitutions of CD3⁺ and CD56⁺ cells were different between the aGVHD⁺ and aGVHD⁻ group. In particular, the percentage of CD3⁻CD56⁺ cells was significantly decreased in patients with aGVHD (P < 0.01). second, the expansion of cd8⁺ (P = 0.01) and CD8⁺ CD28⁻ T cells (P = 0.03) was a characteristic finding in patients with aGVHD. Finally, we found that the percentages of Fas⁺CD8⁺, Fas⁺HLA-DR⁺ and FasL⁺ CD8⁺ cells were significantly increased. Fas antigen was highly coexpressed on most of the lymphocyte subsets, especially on CD8⁺ cells (P < 0.01), and also, significantly higher coexpression of fasl on cd8⁺ cells was found in patients with aGVHD (P < 0.01). in summary, an increase in the percentage of cd8⁺ cells which express Fas and its ligand in patients with aGVHD after BMT points to a possible role for the Fas/FasL pathway in the effector phase of aGVHD.