Role of early estimation of regenerating islet-derived 3-α in hematopoietic stem cell transplantation patients as a prognostic marker for acute lower gastrointestinal graft-vs-host disease

Background Regenerating islet-derived 3-alpha (REG3 alpha) is an antimicrobial protein secreted by Paneth cells with protective effect on intestinal stem cells and prevents any gastrointestinal epithelial damage, as in GUT acute graft-vs-host disease (GVHD). As its plasma concentration correlates with GUT GVHD activity, it could be used as a biomarker for GUT GVHD. Aim The aim was to evaluate the diagnostic and prognostic role of REG3 alpha in hematopoietic stem cell transplantation (HSCT) patients with acute lower gut GVHD. Patients and methods Serum level of REG3 alpha was measured using enzyme-linked immunosorbent assay in 45 allogenic HSCT patients within one week after engraftment in comparison with 20 age-matched and sex-matched healthy controls. It was reevaluated again in a second sample in patients who developed diarrhea owing to acute GUT GVHD or any other causes. Then a third sample of REG3 alpha was measured after 1 week of GUT GVHD treatment. The patients were recruited from Hematopoietic Stem Cells Transplantation Unit (BMT unit) at Ain shams university hospital over the period from 2017 to 2019. Results Serum level of REG3 alpha after engraftment was significantly elevated (> 75 ng/l) in patients who developed later acute lower GUT GVHD compared with other patient groups, with a sensitivity 100% and specificity 93.3%. REG3 alpha was elevated greater than 120 ng/l at the onset of lower GUT GVHD symptoms compared with diarrhea owing to other causes, with a sensitivity 93.33% and specificity 93.33%. After one week of treatment, patients with high levels, that is, greater than 160 ng/l, did not respond to treatment, whereas patients with levels less than or equal to 160 ng/l achieved complete or partial response within 90 days of follow-up. Conclusion REG3 alpha is a useful diagnostic and prognostic biomarker for acute lower GUT GVHD and could be used for early prediction of patients with acute LGI GVHD after HSCT before clinical presentation. (C) 2021 The Egyptian Journal of Haematology