Role of GVHD severity, age, preparative regimen, and donor source on Foxp3 expression following alloBMT. Correlation between Foxp3 gene expression and (A) grade of GVHD, (B) age of recipients, (C) preparative regimens, and (D) donor type were for patients undergoing alloBMT (assessed < 500 days after transplantation). The results include 8 cases of grade I, 8 cases of grade II, 4 cases of grade III, and 2 cases of grade IV acute GVHD. Four patients with limited and 2 patients with extensive chronic GVHD were analyzed. GVHD developed in 11 of 17 MRD recipients, 11 of 13 MUD recipients, and 4 of 4 haploidentical donor recipients. Regression analysis demonstrates negative correlation that does not reach significance (B). ^*Two patients had both acute and chronic GVHD. DLI indicates donor lymphocyte infusion, MRD; matched related donor, MUD; matched unrelated donor. Error bars indicate SEM.