THE IMPACT OF VITAMIN D LEVELS ON PERIPHERAL STEM CELL MOBILIZATION IN ALLOGENEIC HEMATOPOIETIC STEM CELL DONORS


Hocaoğlu E., Yegin Z. A., Özkurt Z. N., Yağcı A. M.

24th Congress of the European Hematology Association, Amsterdam, Netherlands, 13 - 16 June 2019, vol.3, pp.1038

  • Publication Type: Conference Paper / Summary Text
  • Volume: 3
  • City: Amsterdam
  • Country: Netherlands
  • Page Numbers: pp.1038
  • Bursa Uludag University Affiliated: Yes

Abstract

Background: 

Vitamin D is a steroid hormone which has an essential role in many physiological conditions including bone metabolism, immune regulation and hematopoiesis. Vitamin D was indicated to have a favourable impact on hematopoietic stem cell (HSC) production in in-vitro studies. Additionally, animal experiments designated a potential for vitamin D receptor in HSC mobilization. Despite these advances, the possible role of vitamin D in peripheral HSC mobilization remains to be defined.

Aims: 

The aim of this study was to evaluate the impact of pre-mobilization serum vitamin D levels on peripheral HSC mobilization in allogeneic donors.

Methods: 

We investigated the impact of pre-mobilization serum vitamin D levels of 112 allogeneic donors [median age: 39(18-69) years; male/female: 62/50] on peripheral HSC mobilization. All donors had received granulocyte colony stimulating factor (G-CSF) at a dose of 10 mcg/kg/day for 4 days. First HSC apheresis was performed on the fourth day of G-CSF. Serum 25-hydroxy vitamin D levels were measured with immunoassay method before G-CSF administration.

Results: 

Median vitamin D level was found to be 15.8(3-63.2) μg/L in the study population. On the first apheresis day, median peripheral and product CD34(+) cell counts were 36.5(7-206) × 106/kg and 5.3(0.5-22.8) × 106/kg respectively. Median vitamin D levels were significantly lower in donors with low peripheral CD34(+) cell count which was defined as <20 × 106/kg, compared to donors with CD34 level≥20 × 106/kg [13.5(7-27.4) μg/L vs 17(3-63.2) μg/L; p = 0.035] (Figure 1). When we divide the study group into two subgroups based on median vitamin D levels, peripheral CD34(+) cell counts were found to be significantly lower in low-vitamin D group compared to high-vitamin D group [35(7-135) × 106 vs 41.4(10-206) × 106; p = 0.038]. Any significant association was not observed between vitamin D levels and product CD34(+) cell counts. In logistic regression analysis, serum vitamin D level was considered to be correlated with peripheral CD34(+) cell count [p = 0.042; SE: 0.034; 95% Cl Exp(B): 1.003-1.145].

Summary/Conclusion: 

Mobilization failure still remains to be a critical issue for HSC transplantation. In this study, the significant association between vitamin D levels and peripheral CD34(+) cell counts, lacking a similar correlation with product CD34(+) cell counts, requires further evaluation with larger study populations and more standardized procedures including product processing and collection. In these circumstances, the possible role of vitamin D in HSC mobilization deserves further consideration as vitamin D replacement before mobilization would be an easy, safe and cost-effective approach to improve mobilization success.