Donor CD4⁺ T and B220⁺ B cells in transplants were required for chronic GVHD induction. (A) Sublethally irradiated (6.5 Gy [650 rad]) BALB/c recipients were injected with 50 × 10⁶ whole spleen cells (whole-SPL), CD4⁺ T-cell-depleted spleen cells (CD4^--SPL), CD8⁺ T-cell-depleted spleen cells (CD8^--SPL), or B220⁺ B-cell-depleted spleen cells (B220^--SPL). The recipients were checked twice a week for proteinuria, hair loss, and survival. The percentage of mice without proteinuria is shown in the left panel, and the percentage of survival is shown in the right panel. There were 8 mice in each group combined from 2 replicate experiments. (B) HE staining of skin tissue sections of BALB/c recipients given CD4^--SPL cells, CD8^--SPL cells, or B220^--SPL cells. One representative is shown of 4 examined recipients in each group.