High Grades of Amphiregulin Expression in Intestinal Tissue Samples of Pediatric Patients with Severe Acute Graft-Versus-Host Disease after Allogeneic Hematopoietic Cell Transplantation

Introduction 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 was 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. Objectives 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. Methods 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. The median AREG scores between the groups were compared using multivariable linear regression with age and gender as confounders. The study protocol was approved by the Ethical committee of Canton Zürich, Switzerland, number 2022-01037. Results Overall, 59 biopsies were stained for AREG. The 20 patients after HCT had a median age of 6 years (range 1 to 16 years), 19 patients with IBD had a median age of 10 years (range 2 to 16 years), and 20 control patients a median age of 10 years (range 4 to 18 years) at the time of the biopsy. Out of the 20 patients who underwent HCT, 6 patients had severe GvHD (clinical grade 3 to 4), 5 had mild GvHD (clinical grade 1 to 2) and 9 had no GvHD at the time of the biopsy. The median for the AREG overall grade (Figure 1) for control group was 2, for the HCT with severe GvHD group 2.5 (p = 0.060) and for the IBD group 2.5 (p = 0.007). The results for the AREG epithelium and lamina propria grades were similar and are presented in Figures 2a and 2b respectively. We could not show any evidence for a difference in survival between patients with GvHD with overall AREG scores below and greater or equal to the median of 2.5 (Figure 3). Conclusions This study showed significantly higher AREG grades in intestinal biopsies for patients with severe GvHD and IBD compared to the biopsies of controls and patients with mild or no GvHD. These results were consistent in the two separately assessed areas - epithelium and lamina propria.