Fecal calprotectin as a biomarker for the diagnosis of GI-aGvHD

Results from a prospective, observational, single-center study, evaluating fecal calprotectin (FC) as a predictive biomarker for gastrointestinal acute graft-versus-host disease (GI-aGvHD) were published in Bone Marrow Transplantation by Piñero-Pérez et al. FC was measured on Days +7, +14, and +21 after allogeneic hematopoietic stem cell transplantation (allo-HSCT), at GI-aGvHD diagnosis, and 7 days after treatment initiation (N = 165; GI-aGvHD, n = 87). The primary endpoint was the predictive value of FC for GI-aGvHD development.

Key data: FC at Day +7 post-allo-HSCT did not discriminate patients who subsequently developed GI-aGvHD (area under the receiver operating characteristic curve [ROC AUC], 0.50); however, discriminative performance improved on Day +14 (AUC, 0.69; 95% confidence interval [CI], 0.59–0.78; p < 0.001) and Day +21 (AUC, 0.77; 95% CI, 0.65–0.89; p < 0.001). The optimal FC value on Day +21 was 52.5 µg/g (sensitivity, 75%; specificity, 87%). At diagnosis, median FC was 120 µg/g and correlated with endoscopic severity (r = 0.31; p = 0.02) but not clinical or histological grading. Median FC decreased to 51.5 µg/g at 7 days after treatment initiation (p = 0.04).

Key learning: FC measurement between Days +14 and +21 after allo-HSCT may support early identification of patients at risk of GI-aGvHD; however, the single-center nature of this study underscores the need for external validation in independent cohorts before routine clinical implementation.