Prediction of success of CD34+ collection for autotransplantation in children

Introduction > Intensive chemotherapy with autologous stem cell transplantation is a therapeutic tool used in paediatric oncology. In adult patients, a peripheral blood CD34+ cell count superior to 20/mL enables an adequate collection of peripheral blood stem cells. There are no recommen-dations for children. This study aimed to determine whether the count of circulating CD34+ cells on the day before cytapheresis predicts successful collection in paediatric patients.Methods > We retrospectively studied all paediatric patients who underwent apheresis for stem cell autotransplantation in the CHU of Rennes between 2010 and 2019. Successful apheresis was defined as a collection superior to 3 x 106 CD34+/kg. "Success" and "failure" groups were compared.Results > In total, 122 apheresis procedures were performed in 105 patients. It was a successful procedure in 81% of patients and a failure in 19% of patients. A minimal cut-off of circulating CD34 + count superior to 13/mL on D-1 allowed us to predict a collection of at least 3 x 106 CD34+/kg (PPV 94,8%, NPV 51,4%). For children aged < 6 years, the association with leucocyte increase during the 5 days before the procedure improved the prediction of success.Discussion > The peripheral blood CD34+ cell count is a predictive factor for successful collection in paediatric patients. The minimal cut-off that allows an adequate collection of peripheral blood stem cells is inferior to the minimal cut-off in adult patients. Nevertheless, this minimal number of circulating CD34+ cells is insufficient to predict the success or failure of apheresis in patients younger than 6 years of age.