Organ pathology scores and inflammatory cytokine levels in B6D2 mice receiving TCD BM cells plus T_n cells from WT B6 or CCR7^−/− B6 donors. B6D2 recipients were lethally irradiated and then administered 3 × 10⁶ TCD BM cells from WT B6 donors with or without 4 × 10⁶ CD25-depleted T_n cells from either WT B6 or CCR7^−/− B6 donors on day 0. Error bars indicate SEM. (A) Recipient animals were killed between days 18 and 21, and their organs were extracted for pathologic analysis. Organs were assigned a histologic score between 0 and 4 by a pathologist blinded to treatment group using a system described previously. n = 14 WT T_n cell recipients and 12 CCR7^−/− T_n cell recipients. *P = .017, **P < .001 by Mann-Whitney test. (B-C) Recipient animals were killed on transplantation day +15, and their organs were homogenized in a PBS/protease-inhibitor solution. TNF-α and IFN-γ levels were then quantified by ELISA. (B) *P = .017 by Student t test. (C) *P = .052.