SMAD3 deficiency leads to lethal colonic GVHD. (A) Survival curve of BALB.B recipients after injection of 107 BM cells and 5 × 106 splenocytes from syngeneic (BALB.B) or allogeneic WT or SMAD3-KO 129-strain donors. (B-F) Same as in panel A, except that the number of splenocytes was 5 × 105. (B) Survival curve and (C) average weight (with SEM) for surviving mice (at least 10 mice per group). (D) Representative photographs of colon involvement at day 40 in recipients of WT or SMAD3-KO AHCT (0.25-mm scale unit). Virtual slides were scanned with the NanoZoomer, Version 2.0 series system and acquisition software NDP.scan, Version 2.2.17 (Hamamatsu Photonics) using a 40× objective lens. (E) Pathologic grading of large bowel GVHD (n = 8). (F) Relative quantity (compared with internal positive control) of cytokine/marker in colon extracts at day 40. Data are expressed as relative chemiluminescence, as described in “Cytokine measurements” (n = 3). All histograms represent means with SEM. Student t test was used to compare differences between recipients of WT and SMAD3-KO donors; *P < .05.