Thymus histology following transplantation. (A,C) Normal thymus; (B,D) biopsy from DIG107 conducted at 3 months after thymus transplantation. Panels A and B show staining with CD3 antibody (original magnification ×10). Panels C and D show staining with cytokeratin. Positive reaction with antibody is indicated by the brown color. Both cortex (C) and medulla (M) containing light lacy cytokeratin-positive epithelial cells and Hassall bodies are evident in the transplant biopsy from this patient.