Absence of clinical GVHD after FC transplantation. Lethally irradiated B6D2F₁ recipients reconstituted with 2000 B6-derived HSCs alone (n = 8) or HSCs plus 200 000 FCs (n = 9), also from a B6 donor, failed to exhibit significant evidence of GVHD even at 3 weeks after BMT. This is in contrast to HSC+200 000 T_BM recipients (n = 7) in which clinical scores consistent with moderate to severe GVHD were evident (P ≤ .05). Mean ± SE peak clinical scores for each group are shown.