High quality cord blood banking is feasible with delayed clamping practices. The eight-year experience and current status of the national Swedish Cord Blood Bank

Abstract

The National Swedish Cord Blood Bank (NS-CBB) is altruistic and publicly funded. Herein we describe the status of the bank and the impact of delayed versus early clamping on cell number and volume. Cord Blood Units (CBUs) were collected at two University Hospitals in Sweden. Collected volume and nucleated cell content (TNC) were investigated in 146 consecutive Cord Blood (CB) collections sampled during the first quarter of 2012 and in 162 consecutive CB collections done in the first quarter of 2013, before and after clamping practices were changed from immediate to late (60 s) clamping. NS-CBB now holds close to 5000 units whereof 30 % are from non-Caucasian or mixed origins. Delayed clamping had no major effect on collection efficiency. The volume collected was slightly reduced (mean difference, 8.1 ml; 95 % CI, 1.3-15.0 ml; p = 0.02), while cell recovery was not (p = 0.1). The proportion of CBUs that met initial total TNC banking criteria was 60 % using a TNC threshold of 12.5 × 10(8), and 47 % using a threshold of 15 × 10(8) for the early clamping group and 52 and 37 % in the late clamping group. Following implementation of delayed clamping practices at NS-CBB; close to 40 % of the collections in the late clamping group still met the high TNC banking threshold and were eligible for banking, implicating that that cord blood banking is feasible with delayed clamping practices.

The aldehyde dehydrogenase cord blood potency assay excludes early apoptotic cells

“…Many CB donations must be investigated to find these few top units. Currently, at the NSCBB approximately 60% of donations are discarded due to low cell content …”

“…Currently, at the NSCBB approximately 60% of donations are discarded due to low cell content. 11 As stated before, major issues in CB transplantation compared to HSCT with cells from adult donors are the low cell dose in terms of TNC and CD341 cells relative the weight of the recipient, 2 and that all CBUs are cryopreserved and thawed before transplantation, resulting in loss of viability and cells. 13 This means low tolerance for low precision in HSC measurement in CB banking.…”

“…Finally, 0.5 mL was sampled into a separate vial, subjected to controlled rate freezing, and kept in gaseous nitrogen together with the full CBU. This procedure was validated prior to NSCBB FACT/NetCord accreditation in 2013 and showed that CFU assay results from frozen‐thawed CBBCs stored separately in vials correlated with results from the corresponding CBU main bag and contiguous bag segments …”

“…CB was collected for the FACT/NetCord-accredited Swedish national cord blood bank (NSCBB), as described before. 11 Cord blood donations with total TNC above 150 3 10 7 were processed to cord blood buffy coats (CBBCs) of approximately 21 mL using the (Sepax system, Sepax, Biosafe SA, Eysins, Switzerland), and supplemented with freezing solution (10% dimethyl sulfoxide) to a final volume of 25 mL. Finally, 0.5 mL was sampled into a separate vial, subjected to controlled rate freezing, and kept in gaseous nitrogen together with the full CBU.…”

“…This procedure was validated prior to NSCBB FACT/NetCord accreditation in 2013 and showed that CFU assay results from frozen-thawed CBBCs stored separately in vials correlated with results from the corresponding CBU main bag and contiguous bag segments. 11 Nucleated cell counts, CD34 cell enumeration, ALDH analysis, annexin V analysis, and CFU assay on frozen-thawed samples Fifty-seven separately frozen CBBC vials of randomly selected CBUs, included in the NSCBB inventory in 2014, were investigated. In short, cells were thawed, and RBCs lysed with an ammonium chloride-based, buffered solution.…”