Regenerating islet-derived 3-alpha is a biomarker of gastrointestinal graft-versus-host disease

Abstract

There are no plasma biomarkers specific for GVHD of the gastrointestinal (GI) tract, the GVHD target organ most associated with nonrelapse mortality (NRM) following hematopoietic cell transplantation (HCT). Using an unbiased, large-scale, quantitative proteomic discovery approach to identify candidate biomarkers that were increased in plasma from HCT patients with GI GVHD, 74 proteins were increased at least 2-fold; 5 were of GI origin. We validated the lead candidate, REG3α, by ELISA in samples from 1014 HCT patients from 3 transplantation centers. Plasma REG3α concentrations were 3-fold higher in patients at GI GVHD onset than in all other patients and correlated most closely with lower GI GVHD. REG3α concentrations at GVHD onset predicted response to therapy at 4 weeks, 1-year NRM, and 1-year survival (P ≤ .001). In a multivariate analysis, advanced clinical stage, severe histologic damage, and high REG3α concentrations at GVHD diagnosis independently predicted 1-year NRM, which progressively increased with higher numbers of onset risk factors present: 25% for patients with 0 risk factors to 86% with 3 risk factors present (P < .001). REG3α is a plasma biomarker of GI GVHD that can be combined with clinical stage and histologic grade to improve risk stratification of patients.

Figure 1

REG3α concentrations in plasma samples from HCT patients of 2 independent validation sets. (A) University of Michigan patients (n = 871). (B) Regensburg, Germany, and Kyushu, Japan (n = 143). (C) Plasma REG3α concentrations in patients classified by GI symptoms and histologic diagnosis and categorized by conditioning regimen intensity. High-intensity regimens included: cyclophosphamide ± cytarabine, thiotepa, fludarabine and/or TBI; cyclophosphamide/VP-16/BCNU; busulfan + cytarabine, clofarabine, melphalan, cyclophosphamide/anasacrin, or cytarabine/cyclophosphamide; BCNU/VP-16/cytarabine/melphalan; TBI ± VP-16; melphalan. Moderate-intensity regimens included: fludarabine + busulfan or treosulfan ± TBI, melphalan, zevalin, or anasacrin/cytarabine; fludarabine ± TBI, melphalan, or cyclophosphamide; fludarabine/BCNU/melphalan; TBI. (D) Patients classified by symptoms and etiology (n = 675).

Figure 2

ROC curves for patients with post-HCT diarrhea. ROC curves comparing REG3α concentrations for patients with diarrhea caused by GVHD (n = 162) and not caused by GVHD (N = 42). REGα alone (thick blue): AUC = 0.80; IL2Rα (thick brown): AUC = 0.69; Elafin (thick red): AUC = 0.68; IL-8 (thin blue): AUC = 0.61; HGF (thin brown): AUC = 0.61; TNFR1 (thin red): AUC = 0.60; composite of all 6 biomarkers (solid black): AUC = 0.81.

Figure 3

REG3α expression according to severity of GVHD at diagnosis. Patients were classified by volume of diarrhea (A) and histologic grade (B).

Figure 4

Prognostic value of REG3α concentrations at onset of GVHD. (A) Patients were classified by response to GVHD therapy after 4 weeks (N = 160). (B-D) Patients were classified by REG3α concentration: low (≤ 151 ng/mL, n = 81; thin line) and high (> 151 ng/mL, n = 81; thick line). (B) NRM (34% vs 59%, P < .001) (C) Relapse mortality (17% vs 14%, P = .59). (D) One-year survival (48% vs 27%, P = .001). All P values are adjusted for donor source, HLA match, conditioning intensity, recipient age, and baseline disease severity according to the Center for International Blood and Marrow Transplant Research (CIBMTR) guidelines. (E) One-year NRM for patients classified by number of risk factors at GVHD onset, using clinical stage (high risk = stage 2-4) and histologic grade (high risk = grade 4); 0 (purple, NRM = 26%); 1 (red, NRM = 60%); 2 (blue, NRM = 71%); 0 vs 1, P < .001; 1 vs 2, P = .006. (F) One-year NRM for patients classified by number of risk factors at the time of GVHD diagnosis as in panel E and including REG3α concentration (high risk > 151 ng/mL); 0 (purple, NRM = 25%); 1 (red, NRM = 34%); 2 (purple, NRM = 66%); 3 (brown, NRM = 86%); 0 vs 1, P = .2; 1 vs 2, P < .001; 2 vs 3, P < .001.