AABB Accreditation of Cord Blood Banks for Somatic Cell Activities

(such as Isolating MSC from Cord Tissue)

Kathy Loper, MHS, MT(ASCP)

What are somatic cells?

Somatic cells may be scientifically defined as "A cell within the developing or developed organism with the exception of egg and sperm cells".¹ In the context of hematopoietic stem cell transplantation, the term is most often used to refer to non-hematopoietic cells that might be used for other cellular therapies. Pancreatic islet cells for transplantation in diabetic patients are one example of somatic cells. Mesenchymal stromal cells (also called mesenchymal stem cells or MSC) are another somatic cell type. MSCs have received increased attention in recent years.

What are MSC?

MSC are multipotent cells derived from stromal tissue that have the potential of differentiating into other cell types such as bone or cartilage. MSC can be obtained from several different types of tissue, and depending on the tissue source of the MSC, their properties, cell markers, and therapeutic potential will vary.

The three characteristics common to all MSC are: (1) plastic adherence in laboratory culture, (2) the ability to differentiate into osteocytes, chondrocytes and adipocytes in vitro, and (3) their expression of specific cell markers (CD105, CD73, and CD90) and also an absence of the hematopoietic cell markers (CD45, CD14, CD19, and HLA-DR).² While the most studied and the earliest used source for MSC was bone marrow obtained via aspiration, other sources of MSC include umbilical cord blood, umbilical cord tissue (Wharton's jelly), adipose tissue obtained via tumescent liposuction or other means, amniotic fluid, the placenta, skeletal muscle, synovium, and dental pulp.³

Adult MSC populations derived from different sources exhibit significant differences in their cell differentiation in vitro and their behavior during clinical trials in vivo. Several factors need to be considered when examining the variable outcomes (efficacy) and the strength of effectiveness (potency) of these trials. The process of defining and quantifying MSC performance needs to begin in the laboratory where they are prepared for therapy. Important factors influencing human MSC efficacy include the culture conditions utilized for MSC generation, the frequency and dose of cells being administered, the viability and potency of the product, the site of administration, the source and homing capacity of the MSC, and the severity of the underlying disease condition.^1,4,5

Laboratory Preparation of MSC

The protocols for isolation and culture expansion of MSC vary from laboratory to laboratory as the field has not yet matured to reach consistency among either collection methods and procedures or products. Clinical trials with MSC have not only used different laboratories to prepare the cellular product, but have also relied on different tests to characterize the final MSC product.

If cellular therapies with MSC are to become a viable option for widespread clinical use, it is likely that benefits from "off-the-shelf" allogeneic products (rather than autologous personalized products) will need to be demonstrated.

Because the source material of MSC (bone marrow, Wharton's jelly, amnion, etc.) varies among current clinical trials, it is not currently clear which cellular products and preparation regimens will receive regulatory approval in the future.

Family Cord Blood Banks and MSC

Many family cord blood banks now offer a service of collecting, processing and storing MSC products from perinatal tissue. Worldwide, half of family cord blood banks recently reported offering some type of cord tissue storage service. However, a minority of the cord blood banks that offer cord tissue storage are isolating MSC from the tissue prior to cryopreservation. (CordBloodIndustryReport.org)

The laboratory procedures currently in use among family cord blood banks that are storing cord tissue vary widely. Some banks are freezing whole segments of tissue. Some banks mince or dissociate the umbilical cord into small pieces which are either cryopreserved as a tissue product or used as a first step towards culturing a cellular product. The laboratory may or may not use enzymes to help break down the tissue and release cells.

Although the characteristics of a final MSC product can be highly variable, depending on their tissue source and processing, family cord blood banks may not be testing and characterizing these cells at the time of storage since any future potential indication is not known at the time the product is stored.

The Role of AABB Accreditation

For those cord blood banks expanding their services to include somatic cell banking such as MSC, AABB offers accreditation for this activity.

It should be noted that AABB accredits specific activities separately, so not all accredited cord blood banks are also accredited for somatic cell activities. Moreover, AABB only offers somatic cell accreditation to those banks that isolate a cellular product for storage; AABB does not accredit tissue products.

As this burgeoning field matures, the state of the science and the art of practice will also continue to evolve. By accrediting somatic cell activities for cord blood banks and pancreatic islet processing facilities, AABB helps ensure an additional measure of quality. The same rigorous requirements for validated procedures, equipment control and quality controls apply equally to cord blood banking or somatic cell processing and storage activities.

To obtain information on AABB accreditation and apply for accreditation as a cord blood bank or somatic cell processing facility, please contact accreditation@aabb.org.

Facilities that have AABB Somatic Cell Accreditation as of Sept. 2015

    ^* Includes accreditation for pancreatic islet cell processing

Kathy Loper MHS, MT(ASCP) serves as the Senior Director of Cellular Therapies at the AABB Center for Cellular Therapies. She has over 25 years of cell processing and laboratory experience and has authored numerous publications, book chapters and reference texts.

References:

1. Glossary. In: Areman, E. and Loper, K. eds. Cellular Therapy: Principles, Methods and Regulations. 2nd ed. Bethesda, MD. AABB (2015 In press)
2. Kamani, N. Collection of other cells and tissues: In: Areman, E and Loper, K. eds. Cellular Therapy: Principles, Methods and Regulations. 2nd ed. Bethesda, MD. AABB (2015 In press)
3. Phinney DG, Prockop DJ: Concise review: Mesenchymal stem/multipotent stromal cells: The state of transdifferentiation and modes of tissue repair - Current views. Stem Cells 2007; 25:2896-2902. doi: 10.1634/stemcells.2007-0637
4. DiMarino AM, Caplan AL, Bonfield TL, et al: Mesenchymal Stem Cells in Tissue Repair. Frontiers in Immunology 2013; 4:201. doi: 10.3389/fimmu.2013.00201
5. Keating A: Mesenchymal Stromal Cells: New Directions. Cell Stem Cell 2012; 10:709-716 DOI: http://dx.doi.org/10.1016/j.stem.2012.05.015