Macroscopic and microscopic changes in examined mice. (a) TCR-α–/– mice treated with low dose FU plus UVBL. Erythema and alopecia with scaling were observed. (b) Histological findings in TCR-α–/– mice treated with low dose FU plus UVBL. Hyperkeratosis, acanthosis, plugging, liquefaction-like degeneration and perivascular mononuclear cell infiltration were observed. (c) B6 mouse treated with high FU plus UVBL. Alopecia and slight erythema were observed. The degree of skin changes was slightly decreased compared to that of TCR-α–/– mice in Fig. 2a. (d) Histological findings in a B6 mouse treated with high FU plus UVBL. Hyperkeratosis, acanthosis, plugging and mononuclear cell infiltration were observed, but these changes were much milder than those of TCR-α–/– mice in Fig. 2a,b. (e) Control B6 mouse treated with PBS. (f) Histological findings in a control B6 mouse treated with PBS. Marked changes were not observed.