CD4 and graft versus host disease: Indeed, GvHD onset was supported by flow cytometry data showing that mice transplanted with BM+T-cells had a significantly higher population of CD4+ T-effector memory cells (TEM) (H2Kb+ CD4+ CD44+CD62L-) and CD8+ TEM (H2Kb+ CD8+ CD44+CD62L-) in the liver (Figure 3A).