Sheryl Brown-Lewis, BS
American Red Cross
United States
Leading with Innovation and Reliability
In cell and gene therapy, timing can make or break a process. Access to high-quality starting material that is ready when needed is not just helpful; it is essential. With decades of expertise in apheresis collections and a proven track record in supplying leukopaks, the American Red Cross has built a foundation of trust and reliability for therapy developers. Our experience spans research, development, and clinical programs across the United States, giving us unique insight into the evolving needs of this industry.
As advances happened in the field of cell and gene therapy, we saw an opportunity to create a cryopreserved leukopak that could provide the same quality cells as a fresh product while offering greater flexibility for developers. Fresh leukopaks remain the gold standard for many applications, but their time-sensitive nature can create logistical challenges. We recognized that a cryopreserved option could better align with the fast-paced demands of modern therapy development.
This is where the development of a cryopreserved leukopak began. In 2022, our Manufacturing, Science, and Technology (MSAT) team launched a research and development initiative focused on creating a cryopreserved leukopak, a high-quality cell source used in advanced biomedical research, designed to match the performance of our fresh products post-thaw. We explored a range of processing techniques and cryoprotectant formulations to identify the right balance of viability, consistency, and cost-effectiveness.
Through this work, a cryopreserved leukopak was born: a product designed to meet industry standards for quality while providing therapy developers the flexibility to plan with confidence.
Research and Development
Creating a cryopreserved leukopak was not just about freezing cells; it was about engineering a process that would preserve cell integrity, minimize variability, and consistently deliver high post-thaw recovery. From the start, our MSAT team designed the development program to reflect the real-world needs of therapy developers, balancing scientific rigor with scalability and efficiency.
Choosing the cryoprotectant was a key consideration in our development process. We selected BioLife Solutions’ CryoStor®, a well-regarded cryopreservation medium in cell and gene therapy, based on its serum-free and protein-free formulation, which may help reduce variability and support cell integrity during freezing and thawing. This choice reflects our ongoing commitment to quality and compliance across both RUO and GMP offerings and is part of our broader plan to optimize product performance.
Three DMSO concentrations, 0%, 5%, and 10%, were tested as part of a method development protocol, and while both the 5% and 10% DMSO concentrations produced high post-thaw recoveries, 5% DMSO was chosen to proceed forward with validation and implementation for RUO and GMP cleanroom processing and cryopreservation of our cryopreserved leukopaks.
The cryopreserved leukopak is built on a foundation of validated procedures designed to ensure reproducibility and reliability across sites. During the validation phase, we collected 22 leukopaks from our Portland and Philadelphia locations. Portland was chosen deliberately because it is our furthest collection site from the processing lab, allowing us to confirm that our logistics and cold chain controls could maintain product quality over distance and time.
Leukopaks from Portland were shipped in validated containers to our Philadelphia MSAT laboratory, where they were processed and cryopreserved by multiple operators. This step was critical for demonstrating that the process could be replicated, regardless of operator or site, without compromising recovery or viability. Post-thaw evaluations confirmed that the tenth-sized cryopreserved leukopaks (10–30 mL) achieved high recovery rates and strong cell viability.
To access overall recovery and viability, post-thaw evaluations were performed.
To extend these findings, we conducted a smaller validation study for our quarter-sized cryopreserved leukopaks (30–70 mL), with comparable results. We also performed detailed characterization studies on all lots, assessing TBNK cell composition post-thaw using a validated FACSLyric TBNK panel. These studies confirmed that our approach delivers consistent cell profiles, which is vital for clients relying on predictable performance in downstream applications.
A smaller validation was performed to evaluate the quarter-sized (30-70mL final volume) cryopreserved
leukopak with comparable results.
Developing a cryopreserved leukopak was just the beginning. Beyond offering a cryopreserved leukopak as a product, we recognized the value of providing cryopreservation as a service. This means that not only can our clients source cryopreserved leukopaks from us, they can also leverage our expertise and infrastructure for their own collections or specialized needs.
Our labs are designed to manage both small-scale R&D batches and GMP-compliant production. Using cleanrooms and biosafety cabinets, we ensure that each step – from cell processing to cryopreservation – meets the rigorous quality standards required for clinical and commercial use. The flexibility of our protocols allows us to adapt to specific client requirements, whether that involves custom volumes, aliquoting strategies, or unique cryopreservation conditions.
This service approach has become especially valuable for therapy developers who want to secure starting material early, process it according to their specifications, and store it for use when their development or manufacturing schedules demand it. By pairing technical expertise with flexible capabilities, we make it easy for clients to focus on therapy development without worrying about the logistics of cryopreservation.
Every cryopreserved leukopak product and service offering is supported by a robust testing framework. All collections undergo Infectious Disease Marker (IDM) testing to help ensure donor and product safety. For RUO products, sterility testing is performed on pre-cryopreserved material. GMP products undergo a comprehensive testing panel on the cryopreserved material, including sterility, endotoxin, and mycoplasma testing, before release. Each GMP product is delivered with a Certificate of Analysis (COA), and COAs for RUO products are available upon request.
Our storage capabilities are designed for both reliability and scalability. Products are stored in the vapor phase of liquid nitrogen within continuously monitored, high-capacity storage units. This approach ensures consistent ultra-low temperatures while providing real-time oversight of inventory and storage conditions. Stability studies are ongoing to extend the current 24-month shelf life, with early results supporting continued performance up to 48 months.
When it comes to shipping, we have the reach and infrastructure to deliver products worldwide. We use validated dry shippers and partner with both local and commercial couriers to ensure each product arrives in optimal condition. Depending on client needs, shipments can include enhanced monitoring options, such as temperature tracking and location updates, for added confidence.
Post-Thaw Performance and Shelf-Life
The true measure of a cryopreserved leukopak is how it performs once thawed. With our cryopreserved leukopaks, we set the bar high, aiming to match or exceed the quality of our fresh leukopaks. Through extensive characterization and stability studies, we have consistently achieved post-thaw recoveries and trypan blue viabilities of greater than 80% on average. These results are not just numbers – they represent reliability for therapy developers who depend on viable, functional cells for their research and manufacturing processes.
Currently, cryopreserved leukopaks carry a 24-month shelf life, with studies ongoing to confirm performance at 48 months. This long-term stability provides clients with the flexibility to secure critical starting material well in advance, knowing the quality will be maintained over time. It also allows developers to reduce scheduling pressures and the risks associated with fresh collections, such as donor availability or logistical challenges.
Broader Impact: Advancing the Cell and Gene Therapy Pipeline
Our cryopreserved leukopaks are designed as part of a broader strategy to support the entire cell and gene therapy ecosystem. With a ready-to-use, high-viability leukopak, we help therapy developers bridge the gap between research, process development, and clinical manufacturing. This flexibility can be game-changing for teams that are scaling up or moving between clinical phases where consistency and reliability are essential.
The work behind cryopreserved leukopaks also reflects the Red Cross’s broader commitment to innovation. Our nationwide network, extensive donor base, and decades of apheresis expertise position us as a national single-source partner for developers navigating the complexities of cell sourcing. By standardizing our collection and cryopreservation processes, we help reduce variability in starting material, which is critical to achieving predictable results downstream.
As part of our Cell and Gene Therapy Solutions program, cryopreserved leukopaks complement a full suite of services, including donor selection, product characterization, and tailored collection protocols. Together, these offerings make it easier for clients to move from discovery to late-stage development without the need to manage multiple vendors or inconsistent quality standards.
Looking Ahead: Innovation and Commitment
The development of a cryopreserved leukopak is just the start of how we are evolving to meet the needs of a rapidly growing industry. As therapies become more complex and timelines tighten, the demand for reliable, high-quality cryopreserved starting material will only continue to rise.
We are conducting ongoing studies to extend shelf life beyond 48 months and to further optimize post-thaw recovery for a range of applications. In addition, we are exploring advanced automation and real-time quality monitoring to bring even greater consistency across batches. These efforts are guided by the same philosophy that launched cryopreserved leukopaks: listen to our clients, anticipate their needs, and create solutions that improve outcomes across the therapy pipeline.
Our Cell and Gene Therapy Solutions team remains committed to advancing the science of cryopreservation while keeping our processes grounded in practical, client-focused solutions. We know that behind every collection and every batch of cells lies the potential to change a patient’s life, and that belief drives our work every day.
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