Analysis of clinical outcomes in autologous stem cell transplant in relation to CD34+ cell count: A retrospective chart review

Background: Autologous hematopoietic stem cell transplant (Auto-HSCT) is a well-established treatment for various hematologic malignancies, such as lymphoma and multiple myeloma (MM). Auto-HSCT requires stem cells to be collected from the patient themselves after undergoing a conditioning regimen. At our facility, the adequacy of the collected product is assessed through the measurement of CD34+ cells within a sample, as the product must be cryopreserved and subsequently thawed prior to re-infusion into the patient. Rationale: This study aims to determine if our current collection methods reflect an accurate measurement of the number of viable CD34+ cells collected within the product the patient receives. Additionally, we determine if a higher CD34+ cell count correlates with improved clinical outcomes such as time to neutrophil and platelet engraftment, treatment-related infection, intensive care unit (ICU) admission, and platelet transfusion. Methodology: This study was a retrospective chart review of patients who received Auto-HSCT at the Health Sciences Centre in St. John’s, NL, between January 2014 and August 2019. Results: We found that post-thaw viable CD34+ cell count was positively correlated with time to neutrophil engraftment but not to time to platelet engraftment. There was no correlation between post-thaw viable CD34+ cell count and treatment-related infection, ICU admission or platelet transfusion. Conclusion: We did not find any evidence to support a correlation between post-thaw viable CD34+ cell count and clinical outcome; therefore, exploring other means of quality assurance for autologous stem cell transplant products at our institution may be beneficial