During acute GVHD, donor-derived T cells infiltrate the thymus.
Acute (A) or chronic (B) GVHD was induced in unirradiated B6D2F1 mice. Syngeneically transplanted B6D2F1mice served as controls (C), and donor–host chimerism was measured at 2 weeks after transplantation. In the B6→B6D2F1model, mature donor T cells were TCRβhighH-2Kb+Kd−, whereas in the DBA/2→B6D2F1 model, TCRβhighH-2Kb-H-2Kd+ T cells were of donor origin. The background in syngeneically transplanted mice was 0.5% or less. (D) Quantification of donor-derived mature T cells in thymuses of transplanted hosts with acute (▪) or chronic (
) GVHD. Donor cell infiltration is given either as a percentage of all TCRβhigh thymocytes or as an absolute cell number (×10−6) of donor-derived T cells among TCRβhigh cells in the thymus at 1 and 2 weeks after transplantation (mean ± SEM). (E) Loss of DP thymocytes (1/DP) is plotted against the percentage of TCRβhigh infiltrating donor T cells at 1 and 2 weeks after transplantation for both GVHD models. The graph represents pooled data from 2 (chronic GVHD) to 9 (acute GVHD) independent experiments; 5 to 25 mice were analyzed for each group. *P < .01 versus mice with chronic GVHD.#P < .01 versus chronic GVHD at 2 weeks (2-tailed Mann–Whitney U test).
