Allogeneic transplant recipients with GVHD showed increased levels of TGF-β1 in the BAL fluid. Total TGF-β1 was determined by ELISA. Data represent means ± SE of individual or pooled BAL samples, derived from at least two separate experiments. Numbers of mice were: Day 0: 8, 9, and 7; Day 4: 6, 4, and 6; Day 14: 6, 4, and 10; for normal CBA, allogeneic GVHD, and allogeneic no GVHD, respectively. BAL fluids of mock-infected mice were collected at several time points after mock infection. Because we observed no differences in the TGF-β1 levels at different time points after mock infection, the data are presented together. The asterisks indicate a significant difference from both normal CBA and allogeneic no GVHD (P < .05; Student's t-test).