αβ T-cell–deficient recipients but not γδ T-cell–deficient recipients have an increased incidence of cGVHD. (A) Incidence of cGVHD in αβ T-cell–deficient recipients. Combined data from 2 experiments. On day 0, recipient mice were lethally irradiated and reconstituted with 8 × 10⁶ BM cells alone (n = 10, both recipient types) or BM plus 10⁷ spleen cells: WT (n = 29), TCRα^-/- (n = 12). †P < .01 for TCRα^-/- recipients as compared with WT recipients. (B) Clinical disease in αβ T-cell–deficient recipients. Average clinical score for mice affected with cGVHD (unaffected mice are excluded). BM control mice did not get cGVHD and are represented on the graph as scoring “0.” (C) Incidence of cGVHD in γδ T-cell–deficient recipients. Combined data from 3 experiments. On day 0, recipient mice were lethally irradiated and reconstituted with 8 × 10⁶ BM cells alone (n = 28, both recipient types) or BM plus 10⁷ spleen cells: WT (n = 41), TCRδ^-/- (n = 38). (D) Clinical disease in γδ T-cell–deficient recipients. Average clinical score for mice affected with cGVHD (unaffected mice are excluded). BM control mice did not get cGVHD and are represented on the graph as scoring “0.”