ABSTRACT
Background & Aim: Background: Traditionally, ‘fresh’ Hematopoietic progenitors cell (HPC) infusions have been preferred over cryopreserved HPC in Allo-HCT because cryopreservation and thawing leads to cell loss, besides DMSO-related adverse reactions in patients. Emergence of COVID-19 pandemic has severely affected fresh HPC infusions and most professional bodies recommend cryopreservation of HPC products before initiating conditioning chemotherapy. Although some western studies suggest no significant impact of graft manipulation on patient outcome, there is no available data from the developing world.Aim: We compare neutrophil and platelet engraftment in patients undergoing Allo-HCT with fresh and cryopreserved HPC products. Methods, Results & Conclusion: Material and Method: Allo-HCT data from October 2018 to October 2021 were analyzed. Cryopreservation was performed by controlled-rate freezing using 10% DMSO, plasmalyte- A and human albumin ( 1:2:1) as cryoprotectant. Cryopreserved products were stored in vapour-phase of Liquid nitrogen tank. CD34+ enumeration and viablity( by 7-AAD) was done on Flow-cytometry on fresh and post-thaw HPC samples. Neutrophil engraftment was defined as absolute neutrophil count >0.5 ×109/L for 3 days. Platelet engraftment was defined as independence from platelet transfusion for at least 7 days with a platelet count >20 × 109/L. Statistical analysis using Wilcoxon Rank Sum test. Results: Ninety-six patients underwent allo-HCT (46 received fresh and 50 received cryopreserved HPC products) (Table 1). There was no significant difference in neutrophil engraftment with fresh and cryopreserved grafts (p>0.05) in different types of transplants( Matched related/unrelated and haploidentical). 22% (11/50) of cryopreserved graft infusions were associated with Grade-1 DMSO-related adverse reactions, which were managed with symptomatic treatment. Cryopreservation increased the cost of related allogeneic transplants by USD1100. No cryopreserved HPC product was culture positive on microbiological assessment. Conclusion: In our experience, the engraftment kinetics were similar with fresh and cryopreserved HPC products as CD34+cell dose administered was almost the same. Cryopreserved grafts had a median 7% CD34+cell loss, associated with mild DMSO-related adverse reactions and cost increment. Even though, graft cryopreservation is a feasible alternative during the pandemic, it is crucial to ensure graft quality and promptly manage DMSO-related adverse reactions.(Table Presented) Table 1 Comparison of Fresh and cryopreserved HPC products in Allo-HCT
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