Plasma Levels of Retinoids and Carotenoids in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation Given Extracorporeal Photopheresis to Prevent Graft‐Versus‐Host Disease—Analyses From a Randomized Trial

Introduction Whether retinoids and carotenoids impact on graft‐versus‐host disease (GVHD) following allogeneic stem cell transplantation (ASCT) is unknown. Methods We conducted a 1:1 randomized controlled trial with extracorporeal photopheresis for GVHD‐prophylaxis as the intervention. The plasma levels of retinoids and carotenoids were determined at randomization and 3 months after ASCT. Results We found no significant difference in GVHD occurrence and levels of retinoids between the intervention and control groups at either of the two time points. Conclusion Whether routine vitamin A supplementation is warranted for GVHD prevention, needs further study. Our exploratory study highlights the complex role of retinoid homeostasis in immune function during ASCT. Trial Registration ClinicalTrials.gov identifier: NCT03204721