The degree of thymus damage was associated with severity of cGVHD. TCD-BM alone (∼2.5 × 106 cells, non-GVHD) or TCD-BM (2.5 × 106 cells) plus 1 × 106 cells splenocytes (severe-GVHD) or 0.25 × 106 splenocytes (mild-GVHD) from C57BL/6 mice were transplanted into BALB/c mice. Mice were monitored for aGVHD clinical symptoms, cutaneous cGVHD, and survival. Thymus structure were assessed 7, 20, and 40 days after HCT, with H&E staining. (A-C) aGVHD symptom scores, cutaneous cGVHD score, and percentage of survival. Each group contained between 12 and 16 recipients combined from 3 replicate experiments. (D) Picture taken on day 40 after HCT (1, non-GVHD; 2, Mild-GVHD; and 3, severe-GVHD). (E) The appearance of the thymus (n = 3) and thymus cellularity of each group results are shown as mean ± standard error (SE) (n = 6). (F) Representative photomicrographs of H&E-stained thymus tissue section and thymus pathology score, results are shown as mean ± SE (n = 6); scale bar, 50 μm. (G) Forty days after transplantation, thymuses were harvested and identified via immunofluorescent staining of CK8 (purple, highly expressed in cortex and lowly expressed in medulla) and CK5 (red, expressed in medulla), and medulla area was measured and shown as mean ± SE (n = 6); scale bar, 50 μm.
