Arizona has state legislation around cord blood education that follows the Institute of Medicine guidelines and mandates/encourages physicians to educate expectant parents about ALL forms of cord blood banking. The Arizona bill was enacted 26 Jan. 2006 and became 1 Jan. 2007.
- What are TNC, MNC, CD34+, and CFU, and why should I care?
These are all ways of counting cell types, and they tell you whether or not your cord blood collection has lots of stem cells and if they are healthy.
Stem cells happen to be Mono-Nuclear Cells or MNC: when you look at them under a microscope there is only one nucleus. Unfortunately, one of the most difficult aspects of stem cell biology is that you can't identify a stem cell just by looking at it. There are other types of blood cells which are also MNC, such as nucleated red blood cells. The only proof that a cell is a stem cell comes from how it behaves when it multiplies.
Scientists have worked for years to develop various chemical stains which have a high affinity for stem cells. The best known marker for blood-forming stem cells is that they test positive for CD34, a protein found on the surface of stem cells. But, CD34+ counts are not an accurate measure of stem cells: CD34+ results vary between labs, they can vary within a single lab, and only 1-2% of the MNC that have CD34+ are actually stem cells.
The Total Nucleated Cell count or TNC is the test most often reported as a measure of the cell count after cord blood processing. The main advantage of measuring TNC is that the count is highly reproducible within and among labs, so it can be used accurately throughout the blood banking community. Even better, the TNC count can be automated with the use of a device called a flow cytometer.
At present Colony Forming Units or CFU are considered to be the best measure of whether stem cells are "viable", or quite frankly alive. The TNC count includes both living and dead cells. In the CFU test a small portion is watched under controlled conditions to see if stem cells divide and form colonies. This used to be a subjective measure, but recently it has been standardized with technology to image the cells and count colonies in the image. The only remaining problem with the test is that it takes days for colonies to grow.
- What questions should parents ask a Family Bank about the Storage Facility?
- What type of records do parents receive after storage?
- Does your contract state that the storage fee is fixed, or may it increase later?
- Does the bank reserve the right, in your contract, to change storage facilities?
- Does the bank operate their own storage facility, or is it provided by another laboratory?
- What type of accreditation or other certifications does the storage facility carry? In most banks the cord blood is stored in the lab where it was processed, and the accreditation of the lab covers the storage conditions.
- What is the geographic location of the storage facility: Is it at risk for hurricanes, earthquakes, or other natural disasters?
- What type of back-up systems does the storage facility have in case of power failure?
- What type of security systems does the storage facility have?
- What is HLA Type and how is it used?
The term "HLA" is short for Human Leukocyte Antigens, and these are proteins in the immune system that determine whether a patient will react against a donor transplant. A very good basic tutorial about HLA types is on the Stanford Website, and the national Be The Match program (aka NMDP) has more info on the role of HLA type in transplants of stem cells from bone marrow or cord blood.
Briefly, there are 6 HLA types that are important for stem cell transplants: in a bone marrow transplant the patient and donor must match at all 6 (100% match), whereas a cord blood transplant is just as effective at curing patients with only a 4 out of 6 match (67% match) between donor and patient. This is the reason that donations to the national cord blood inventory managed by NMDP are so important to help patients who come from minority or mixed racial backgrounds.
The HLA type of cord blood is always measured by public banks, and then the type is listed on a registry that can be searched by patients seeking a transplant. Family banks typically do not measure the HLA type at the time of banking, because it is an expensive lab test and and can always be checked later from a testing segment of the stored cells.