Cell cycle progression of host-derived TN thymocytes is impaired in GVHD.

Acute or chronic GVHD was induced in unirradiated B6D2F₁mice. Untransplanted or syngeneically transplanted B6D2F₁mice served as controls. Thymocytes were analyzed at 2 weeks after transplantation for surface expression of CD4, CD8, and TCRβ and for the incorporation of BrdU into cellular DNA.(A) Representative flow cytometric analysis of thymocytes from a mouse with acute GVHD. (B, C) Frequencies of TN thymocytes (%; mean ± SEM) was assessed by flow cytometry of thymuses from untransplanted (▨) or syngeneically transplanted (□) B6D2F₁ mice and from mice with acute (▪) and chronic () GVHD, respectively. Lower panels show absolute numbers of cycling cells (mean ± SEM; ×10⁻³) among TN thymocytes and represent pooled data from 2 independent experiments; 3 to 5 mice were analyzed for each group. ^*P < .01 versus mice with chronic GVHD and syngeneic controls, respectively. ^†P < .01 versus syngeneic controls (ANOVA).