ABSTRACT
Introduction: Matched unrelated donors (MUD) for hematopoietic progenitor cell (HPC) transplantation are facilitated through the National Marrow Donor Program. Most peripheral blood collections (HPC-A) are obtained in a single day apheresis collection. Extensive planning is required to coordinate the mobilization, collection, and shipment of the product with the conditioning and infusing at the transplant center. Typically, these products are infused fresh, although the COVID pandemic has necessitated cryopreservation in many instances. It was perceived that the number of two-day MUD collections was increasing at our institution. This study was performed to determine if this was true and to evaluate potential causes. Method(s): The project was considered a laboratory quality improvement project;IRB approval was not required per institutional guideline. Data was collected retrospectively for 120 HPC(A) MUD from August 2017-November 2020 including donor's age, weight, and sex, along with recipient to donor weight ratio. Each factor was analyzed against CD34 yield per day of collection. Result(s): Of the 120 donors, 5.6% collected over 2 days in 2017(n=1), 3.7 % (n=1, 2018), 3.6 % (n=1, 2019) with highest observation 17% (n=8) in 2020 (Image). Donor age, donor weight, donor sex, and recipient to donor weight ratio were compared to absolute CD34 yield. There was not a correlation seen between CD34 yield and donor age nor weight. However, donor sex along with recipient/donor weight ratio each showed a correlation in the number of collections required. Of those requiring a second day of collection, 73% were female while 27% were male. Two-day collections could be predicted with 83% accuracy in female with >1.09 recipient/donor weight ratio and male with > 1.49 recipient/donor weight ratio.(Figure Presented) Conclusion(s): The observed trend of increased 2-day NMDP collections coincided with an increase in frequency of female donors. Not surprisingly, higher recipient/donor weight was associated with a higher likelihood of 2-day collections. The size and scope of this study do not allow us to determine a definitive cause. However, it was noted these findings coincided with new donor selection guidelines prioritizing HLA-DP match potentially leading to an increase in female donors being selected. Unexpected two-day collection can have significant effects on transplantation. Developing a predictive algorithm with 83% accuracy allows for patient and staff preparation to anticipate the likelihood for additional collections. Having the product collected and received in advance, prior to patient conditioning improves logistics and removes some variability from scheduling. Larger, multicenter studies are required to determine if increased numbers of two-day collection of MUD are occurring at other centers and to the potential causesCopyright © 2023 American Society for Transplantation and Cellular Therapy
ABSTRACT
Background & Aim: Hematopoietic progenitor cells (HPCs) are infused for hematopoietic reconstitution in the setting of malignancy and inherited or acquired hematological deficiencies. Given the global COVID-19 pandemic, the recommendation was made to cryopreserve all allogeneic HPCs to protect recipients by allowing for subclinical cases of infection to present prior to infusion. As such, consideration of HPC stability programs (SP) and their rigor has risen. The goal of a SP is to prove the rigor of a transplant program’s cryopreservation and storage standard operating procedures so that sufficient HPC viability and potency are maintained for engraftment. SPs are also required by accreditation agencies such as AABB and FACT. Many HPC SP have validated product expirations out to 10 years. Here we share our SP to 20 years with ongoing validation for 30-year expiration. Methods, Results & Conclusion: Program Design: Current testing frequency of our SP is within the first year, and then at three-year intervals (3, 6, 9, 12, 15, 19, 21). Our rolling SP includes 2 additional (Figure Presented) Fig. 1.Current vs proposed HPC product testing and cryopreseveration schema. samples tested at 0, 5, & 9 years, then at 3-year intervals (12, 15, 19, 21, 24, 27, 30). SP samples are collected from donors requiring additional days to reach their goal but are in excess at the conclusion of collection (e.g., Day 1 collection 4.5e6 CD34+ cells/Kg, goal 5e6 CD34+ cells/ Kg). Samples are collected on a quarterly basis with ten 1mL cryovials being drawn (Figure 1). CD3+ and CD34+ viabilities are tested after cryopreservation with an acceptable threshold set at ≥75% for both. Conclusion: We are validating our SP up to 20 years with intention to validate to 30 years. Thus far, our SP reveals product age has no to low correlation with engraftment, suggesting maintenance of potency over time in a cryopreservative of 10% DMSO, 10% plasma, and 30% PlasmaLyte-A with a final cell concentration of ≤3×108 NC/mL (Figure 2). Successful engraftment has been seen in all recipients. Transplant programs should modify testing frequency, acceptance criteria, and product expiration to meet individual need while working towards standardization in the field. Given the frequency of DLIs and 2nd/3rd transplants at the Mayo Clinic, a 30-year SP reflects the need of our transplant program.(Figure Presented)Fig. 2 . ANC and platelet engraftment dates for ≥10-year-old HPC products