Abdolhamed Kian - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Sayeh Parkhideh - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Haniyeh Ghaffari Nazari - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Maryam Nikoonezhad - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Arsalan Jalili - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Shaghayegh Shahsavan - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Abbas Hajifathali - Hematopoietic Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Background: Parathyroid hormone (PTH) is a calcium homeostasis regulator and can affect bone marrow niche. PTH leads to the bone marrow stem cell niche expansion as well as the induction of stem cell mobilization from the bone marrow into peripheral blood. In this study, we evaluated the association between pre- transplantation serum PTH levels and the number of circulating CD۳۴+ cells along with the platelets/white blood cells (Plt/WBC) engraftment in patients who underwent autologous Hematopoietic Stem Cell Transplantation . Methods: Subjects for the study were ۱۰۰ patients who received autologous hematopoietic stem cell transplantation (auto-HSCT), retrospectively. Serum levels of PTH, calcium, phosphorus, and alkaline phosphatase were measured before mobilization. Their impacts were measured on the number of mobilized CD۳۴+ hematopoietic stem cells, and Plt/WBC engraftment. Results: High levels of serum PTH (> ۶۳.۱۰ pg/mL) was significantly associated with higher number of CD۳۴+ cells in peripheral blood after granulocyte- colony stimulating factor (G-CSF)-induced mobilization (p= ۰.۰۷۹*). Serum calcium at low levels were associated with higher number of circulating CD۳۴+ cells post mobilization. Pre- transplantation serum levels of phosphorus and alkaline phosphatase on CD۳۴+ numbers were not statistically significant. Serum Plt/WBC engraftment was not improved in presence of high levels of serum PTH. Conclusions: We suggested that serum PTH levels before transplantation could be influential in raising the number of circulating CD۳۴+ hematopoietic stem cell after mobilization.

Auto-HSCT, CD۳۴+ Cell, Pre- transplant PTH.