TY - JOUR T1 - The influence of cell concentration at cryopreservation on neutrophil engraftment after autologous peripheral blood stem cell transplantation JO - Hematology, Transfusion and Cell Therapy T2 - AU - Félix,Olga Margareth Wanderley de Oliveira AU - Tunes,Gisela AU - Ginani,Valéria Cortez AU - Simões,Paulo César AU - Barros,Daniele Porto AU - Delbuono,Elizabete AU - Alves,Maria Teresa de Seixas AU - Petrilli,Antonio Sérgio AU - Lee,Maria Lúcia de Martino AU - Gouveia,Roseane Vasconcelos AU - Zecchin,Victor Gottardello AU - Seber,Adriana SN - 25311379 M3 - 10.1016/j.htct.2018.01.007 DO - 10.1016/j.htct.2018.01.007 UR - http://www.htct.com.br/en-the-influence-cell-concentration-at-articulo-S2531137918300555 AB - BackgroundPeripheral blood stem cell concentrations are traditionally adjusted to 20–40×106leukocytes/mL prior to freezing. This low cell concentration at cryopreservation implies larger volumes with more dimethyl sulfoxide being used, and higher cost and toxicity at the time of transplant. Higher cell concentrations have been reported but this is not widely accepted. Moreover, the influence of cell concentration on engraftment has not been well documented. Therefore, this study retrospectively analyzed the influence of peripheral blood stem cell concentration at freezing on engraftment after autologous hematopoietic stem cell transplantation. MethodLeukapheresis products were plasma-depleted and cryopreserved with 5% dimethyl sulfoxide, 6% hydroxyethylamide solution and 4% albumin in a −80°C freezer. Individual patient data from hospital records were reviewed. ResultsFifty consecutive patients with oncological diseases underwent 88 leukaphereses. Median age was six years (range: 1–32 years) and median weight was 19kg (range: 8–94kg). Median leukocyte concentration was 109×106/mL at collection and 359×106 (range: 58–676×106) at freezing with 78% viability (range: 53–95%); leukocyte recovery after thawing was 95% (range: 70–100%). In multivariate analysis, cell concentration (p-value=0.001) had a negative impact on engraftment. Patients infused with bags frozen with <200×106leukocytes/mL engrafted after a median of nine days (range: 8–12 days), 200–400×106leukocytes/mL after 11 days (range: 9–20 days); 400–600×106leukocytes/mL after 12 days (range: 8–19 days) and with cell concentrations >600×106leukocytes/mL, engraftment was after 14 days (range: 13–22 days). ConclusionIn patients with adequate CD34 cell collections, total leukocyte concentrations of 282×106/mL, freezing with 5% dimethyl sulfoxide and 6% hydroxyethylamide solution without a controlled-rate freezer, and storing cells at −80°C yielded excellent engraftment. Further increases in cell concentration may delay engraftment, without affecting safety. ER -