Identification of a plasma immune marker panel for early detection of acute graft-versus-host disease in children

• Validation of the immune marker panel consisting of CCL17, galectin-1, and Reg3a shows 95% accuracy in predicting aGvHD grade II-IV. • The identified immune marker panel enables the development of an individualized approach in preventing and treating aGvHD in pediatric HCT. Acute Graft-versus-Host-Disease (aGvHD) is a common complication following allogeneic hematological cell transplantation (HCT), significantly contributing to treatment-related-morbidity and -mortality. Predictive aGvHD plasma markers are currently lacking for pediatric HCT-recipients. In this two-stage retrospective cohort study, we applied least absolute shrinkage and selection operator (LASSO) logistic regression on Olink Immuno-Oncology data to identify plasma immune markers potentially predicting aGvHD grade II-IV in pediatric HCT-recipients. A total of 223 children and young adults were included and divided into a training (n=165) and test cohort (n=58). Overall, 20.1% of patients developed aGvHD grade I and 29.6% grade II-IV. Biobanked EDTA-plasma samples were collected one week prior to aGvHD diagnosis, or at a matched timepoint for non-aGvHD patients. LASSO regression applied to the training cohort data identified plasma immune markers that were subsequently validated and quantified in absolute concentrations in the test cohort. The final selected immune marker panel consisted of CCL17 and galectin-1, combined with either CXCL10 and IL6, or with Reg3a. The calculated area under the curve (AUC) of the receiver operator characteristic (ROC) curve was 0.9 for the panel combining CCL17, galectin-1, CXCL10, and IL6, with 75% sensitivity, 86% specificity, 75% positive predictive value (PPV), and 86% negative predictive value (NPV). The panel combining CCL17, galectin-1, and Reg3a performed even better (p < 0.001) with an AUC of 0.95, 92% sensitivity, 86% specificity, 79% PPV, and 95% NPV. Pending prospective validation, the identified immune marker panel is the first to potentially predict aGvHD, approximately one week prior to onset of symptoms, in pediatric HCT-recipients.