Introduction of principles of blood management to healthy donor bone marrow harvesting

Bone Marrow Harvest: A White Paper of Best Practices by the NMDP Marrow Alliance

Data on recent bone marrow harvest (BMH) collections from the NMDP has shown that bone marrow (BM) quality has decreased based on total nucleated cell count in the product. To ensure that quality BM products are available to all recipients, the NMDP Marrow Alliance was formed in April 2021 to increase the capability of BM collection centers to safely deliver high-quality products consistently and to identify and disseminate guidelines for performing BMH. This white paper describes the best practices for BMH as defined by the NMDP Marrow Alliance.

Supportive Care of Hematopoietic Stem Cell Donors

Supportive care needs for hematopoietic stem cell recipients have been studied. Less is known about the care needs of stem cell donors. Care challenges arise at donor selection, preparation for the donation, the donation procedure and the immediate and long-term after-care. Care needs were analyzed for 1,831 consecutive bone marrow and peripheral stem cell donors at MedStar Georgetown University Hospital between January 2018 and August 2023 in support of a review of the current literature. During the selection, related donors may experience psychological pressures affecting their motivation, while donation centers may be willing to accept co-morbidities in these donors which might preclude donation in unrelated peers. For bone marrow donations, it is important to select donors not only according to optimal genetic matching criteria but also according to suitable donor/recipient weight ratios, to facilitate sufficient stem cell yields. During the donation preparation phase, side effects and complications related to stem cell stimulation must be anticipated and managed for peripheral cell donors, while the pros and cons of autologous blood donation should be evaluated carefully for bone marrow donors. The stem cell donation procedure itself carries potential side effects and complications as well. Peripheral cell donors may require a central line and may encounter hypocalcemia, thrombocytopenia, and anemia. Bone marrow donors face risks associated with anesthesia, blood loss and pain. Post-procedure care focusses on pain management, blood cell recovery and the psychological support necessary to regain a high quality-of-life existence. Hematopoietic stem donors are giving part of themselves to save another's life. They deserve comprehensive supportive care to accompany them throughout the donation process.

Small volume bone marrow aspirates with high progenitor cell concentrations maximize cell therapy dose manufacture and substantially reduce donor hemoglobin loss

BACKGROUND

Bone marrow (BM) transplantation is a life-saving therapy for hematological diseases, and the BM harbors also highly useful (progenitor) cell types for novel cell therapies manufacture. Yet, the BM collection technique is not standardized.

METHODS

Benchmarking our collection efficiency to BM collections worldwide (N = 1248), we noted a great variability of total nucleated cell (TNC) yields in BM products (HPC-M) with superior performance of our center, where we have implemented a small volume aspirate policy. Thus, we next prospectively aimed to assess the impact of BM collection technique on HPC-M quality. For each BM collection (N = 20 donors), small volume (3 mL) and large volume (10 mL) BM aspirates were sampled at 3 time points and analyzed for cell composition.

RESULTS

Compared to large volume aspirates, small volume aspirates concentrated more TNCs, immune cells, platelets, hematopoietic stem/progenitor cells, mesenchymal stromal cells (MSCs), and endothelial progenitors. Inversely, the hemoglobin concentration was higher in large volume aspirates indicating more hemoglobin loss. Manufacturing and dosing scenarios showed that small volume aspirates save up to 42% BM volume and 44% hemoglobin for HPC-M donors. Moreover, MSC production efficiency can be increased by more than 150%.

CONCLUSIONS

We propose to consider small volume BM aspiration as standard technique for BM collection.

Basic characteristics and safety of donation in related and unrelated haematopoietic progenitor cell donors - first 10 years of prospective donor follow-up of Swiss donors

Since July 2007 prospective life-long follow-up (FU) for unrelated (URD) and related donors (RD) is mandatory in Switzerland and data on every allogeneic haematopoietic progenitor cell (HPC) donation are collected prospectively. We report the real-world experience of HPC donation during a 10-year study period (01.07.2007-30.06.2017) with basic characteristics and FU data. 1105 donors underwent 1155 HPC donation procedures. Eighty percent of first donations performed by 802 (73%) RDs and 303 (27%) URDs were peripheral blood stem cells (PBSC), 20% bone marrow (BM). Male donors were over-represented as URD (60% male vs 40% female). Main differences between RDs and URDs concerned age and pre-existing health disorders. RDs were significantly older at first donation (median age 48 years) compared to URD (34 years, p < 0.0001) and had more pre-existing health problems: 25% vs 9% in URD (p < 0.0001). No fatal complications occurred, collection related severe adverse events (SAE) after first donation were not significantly different between groups (RD 1.2%, URD 0.99%), incidence rates for neoplastic and autoimmune diseases did not exceed the rates of the general population. RDs are a more heterogeneous and potentially more vulnerable group, but if donor evaluation is performed appropriately, HPC donation is still safe.

Generation and validation of a formula to calculate hemoglobin loss on a cohort of healthy adults subjected to controlled blood loss

Background

The ability to approximate intra-operative hemoglobin loss with reasonable precision and linearity is prerequisite for determination of a relevant surgical outcome parameter: This information enables comparison of surgical procedures between different techniques, surgeons or hospitals, and supports anticipation of transfusion needs. Different formulas have been proposed, but none of them were validated for accuracy, precision and linearity against a cohort with precisely measured hemoglobin loss and, possibly for that reason, neither has established itself as gold standard. We sought to identify the minimal dataset needed to generate reasonably precise and accurate hemoglobin loss prediction tools and to derive and validate an estimation formula.

Methods

Routinely available clinical and laboratory data from a cohort of 401 healthy individuals with controlled hemoglobin loss between 29 and 233 g were extracted from medical charts. Supervised learning algorithms were applied to identify a minimal data set and to generate and validate a formula for calculation of hemoglobin loss.

Results

Of the classical supervised learning algorithms applied, the linear and Ridge regression models performed at least as well as the more complex models. Most straightforward to analyze and check for robustness, we proceeded with linear regression. Weight, height, sex and hemoglobin concentration before and on the morning after the intervention were sufficient to generate a formula for estimation of hemoglobin loss. The resulting model yields an outstanding R² of 53.2% with similar precision throughout the entire range of volumes or donor sizes, thereby meaningfully outperforming previously proposed medical models.

Conclusions

The resulting formula will allow objective benchmarking of surgical blood loss, enabling informed decision making as to the need for pre-operative type-and-cross only vs. reservation of packed red cell units, depending on a patient’s anemia tolerance, and thus contributing to resource management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02783-9.