The principal cause of mortality and morbidity following hematopoietic cell transplantation (HCT) is graft-versus-host disease (GVHD). Studies in murine models have revealed that inflammatory mediators such as tumor necrosis factor-alpha (TNF-alpha) promote destruction of host tissue following HCT. Elevated plasma levels of soluble TNF receptor 1 have been associated with patients with GVHD and blocking TNF-alpha in experimental models has shown a reduced incidence of GVHD. Based on this finding, patients with new onset GVHD were treated with steroids plus the TNF-alpha inhibitor, etanercept, on a previously reported pilot trial (n=20) and a phase 2 trial (n=41) and their outcomes were compared with those of contemporaneous patients with GVHD (n=99) whose initial therapy was steroids alone. Patients treated with etanercept were more likely to achieve CR than were patients treated with steroids alone. Plasma TNFR1 levels, a biomarker for GVHD activity, were elevated at GVHD onset and decreased significantly only in patients with CR. A four protein fingerprint of IL-2Ralpha, TNFR1, IL-8, and HGF in the plasma has been identified to predict whether a patient will be at high-risk for GVHD based on biomarker analysis. In univariate and multivariate analysis, this four-protein fingerprint has shown a strong association with the grade of acute GVHD, and it can stratify patients into low- and high-risk groups and can be used as a laboratory-based screening method, to diagnose and perhaps treat patients preemptively.