High Amphiregulin Expression in Intestinal Biopsies of Pediatric Patients with Severe Acute Graft-Versus-Host Disease

Acute graft-versus-host disease (GvHD) is a major complication of hematopoietic cell transplantation (HCT). Despite of recent advances in prophylaxis, diagnosis and treatment it is still a serious cause of morbidity and mortality after HCT. Amphiregulin (AREG) is an epidermal growth factor receptor ligand known for restoring damaged intestinal tissue. AREG has been studied as a blood biomarker in acute GvHD and was found predictive of steroid response and mortality. However, the expression of AREG in intestinal tissue in pediatric patients with acute GvHD is unknown. The aim of this study is to analyze and evaluate AREG expression in intestinal tissue biopsies of pediatric patients with GvHD, in comparison to patients with inflammatory bowel disease (IBD) and a control group with no pathological findings to provide insights in the biological tissue expression of this potential diagnostic and prognostic biomarker. We performed a retrospective study with pediatric patients who had an intestinal biopsy performed after HCT between 2010 and 2021, patients who had a diagnosis of IBD and patients with normal findings at the University Children's Hospital Zurich. Intestinal biopsies were stained for AREG. We used a semi-quantitative score ranging from 0 (not present) to 3 (intense) to grade the AREG expression. The grading was performed by a pathologist blinded to the group allocation. Lerner scores were also performed. The median AREG scores between the groups were compared using multivariable linear regression with age and sex as confounders. The study protocol was approved by the Ethical committee of Canton Zürich, Switzerland, number 2022-01037. Overall, 59 biopsies were stained for AREG, 20 after HCT (6 patients with severe GvHD, 5 with mild GvHD and 9 without GvHD), 19 with IBD and 20 controls. The median for the AREG overall grade for control group was 2, for the HCT with severe GvHD group 2.5 (P = .060) and for the IBD group 2.5 (P = .007). The results for the AREG epithelium and lamina propria grades were similar. There were no differences in survival between patients with GvHD with overall AREG scores below and greater or equal to the median of 2.5. This study showed that AREG scores were higher in intestinal biopsies from patients with severe GvHD and IBD compared to controls and patients with mild or no GvHD. Consequently, AREG staining could potentially be used as an additional marker for severe inflammation as seen in GvHD and IBD.