Yigenoglu, Tugce NurUlu, Bahar UncuNamdaroglu, SinemErkurt, Mehmet AliSahin, RasimOkumus, NazikYilmaz, Seda2026-04-042026-04-0420251473-05021878-1683https://doi.org/10.1016/j.transci.2024.104054https://hdl.handle.net/11616/109409Objective: Vitamin D deficiency is common in adult patients undergoing allogenic hematopoietic stem cell transplantation (allo-HSCT). Since vitamin D is an important regulatory factor for the immune system, vitamin D deficiency may have effects on antitumor activity, relapse rates, graft versus host disease (GVHD) occurrence and infection rates in allo-HSCT. We aimed to investigate the effects of vitamin D levels on the outcome of allo-HSCT. Material and methods: This study included 211 patients who underwent allo-HSCT at seven transplant centers in T & uuml;rkiye. The impact of pretransplant vitamin D level on overall survival (OS), relapse rate, GVHD occurrence and engraftment times was analyzed retrospectively Results: Pretransplant vitamin D levels were not related to the neutrophil engraftment day (p: 0.887), relapse rate (p: 0.433) and GVHD occurrence (p: 0.391). At a median follow-up of 14 months, OS was 84.8 % and median OS was not reached. Univariate Cox Regression analysis showed that higher levels of vitamin D (>12 ng/mL) affected the survival rates (p = 0.029) (HR: 0.392: 95 % CI: 10.170-0.907). Conclusion: In our study, pretransplant vitamin D levels were not related to GVHD occurrence, relapse rate and engraftment times. However, we found that higher levels of pretransplant vitamin D levels (threshold is 12 ng/ mL) were associated with increased survival. Further studies with a larger population are necessary to reveal the role of vitamin D in patients undergoing allo-HSCT.eninfo:eu-repo/semantics/openAccessAllogeneic hematopoietic stem celltransplantationVitamin DGraft vs host diseaseArticle6413970978710.1016/j.transci.2024.1040542-s2.0-85212619924Q3WOS:001395124800001Q40000-0003-3173-76140000-0001-6872-37800000-0002-3285-417X0000-0002-6230-95190000-0002-7222-499X