Loss of Gas6 protected recipient mice from non–T cell–depleted allogeneic BMT against hepatic GVHD. C57BL/6 mice received total body irradiation and bone marrow cells (BMCs) from FVB mice; recipients were killed at day 28. (A) Full bone marrow chimerism of recipient. Expression of H-2^q (left panel) and H-2^b (right panel) in a recipient 28 days after bone marrow transplantation (BMT) was determined by flow cytometry (in red). A C57BL/6 mouse that was not transplanted is shown (black line) as control. (B) Liver histology: hematoxylin and eosin staining. Arrow indicates infiltration of portal spaces by mononuclear cells. Scale bar represents 100 μm. (C) Percentage of infiltrated portal spaces are mean ± SEM (n = 5-10; analysis of variance, *P < .05, **P < .01, ***P < .001); WT (■) and Gas6^−/− recipients (□). (D) Apoptotic cells in portal spaces were TUNEL⁺ (brown dark precipitate). Scale bar represents 100 μm.