Why PCT? – Personal Cell Therapy
Allogeneic cells represent a robust business model for tissue banks and ultimately for big pharma who will industrialize them once approved through the FDA. Tissue banks selling umbilical cord stem cells have popped up left and right selling a host of products; live cells, radiated sterile dead cells, and in different quantities for immediate deployment. These cells are billed as young, healthy, vibrant cells having just come from a new birth. A lot of questions remain about using someone else’s stem cells, containing foreign DNA. From a scientific and physician’s point of view, the proof that allogeneic cells are equal or superior to one’s own cells is certainly lacking and has kept us, for now, working with autologous stem cells.
The safety issue remains to be supported by objective research but an absence of information does not imply that foreign cells are better than your own. Generally, the burden of safety proof must lie on the foreign cells since they are the non-self being introduced into one’s body. When foreign cells are introduced in the stem state, they have few immune markers and will generally have little to no immune reaction for that reason. They get a “free pass” as “safe” in a lot of cases. But, are stem cells different just because the effect is not detected the first weeks after treatment? Has anyone looked at what happens down the road when those cells differentiate into the cells that came from the donor? Do we know the long-term consequences of a person receiving a significant load of foreign DNA through multiple stem cell treatments over time with allogeneic cells? Immune reactions to receiving someone else’s DNA are well documented and reports show that foreign cell transplants are not as safe as suggested (Jacobsohn, Acute Graft Versus Host Disease, Orphanet Journal of Rare Diseases, 2007). The cells might be safe initially, but as they grow and differentiate into functional tissue, your patients could have a serious problem and end up with acute graft versus host disease. This has also been documented with recent reports on matched bone marrow transplants (Holmqvist, Chen, Wu, Assessment of Late Mortality Risk After Allogeneic Blood or Marrow Transplantation in Children, JAMA Oncology, July 26, 2018).
We also have real concerns about transmission of disease. Tissue banks screen for certain viruses (usually around 7-15 tests depending on the bank protocols). But what about Parvo virus B19, Arboviruses, Zika virus, Hepatitis G and transfusion related virus TTV to name a few? There’s a new polio-like virus that’s currently affecting a number of children. Are there other viruses that are responsible for human disease that could come from another person? Of course the answer is yes. Only cells that come from your own body that undergo sterile isolation or processing have no risk of communicable disease transmission.
Also, what prions do these banks screen for? Prions cannot be destroyed using current techniques for inactivating pathogens in the human blood supply. These immune and infectious risks are generally low enough that a risk-benefit analysis generally supports the use of allogeneic cells for certain cases. But the risk exists.
Your own stem cells provide your patients with the safest cell therapy option we know of for now. Using sterile technique, you cannot infect your patient with cells that have already been in their own body and there certainly is no chance of rejection. CSN uses adipose derived stem cells (ADSCs) because these cells are generally quite young and healthy relatively speaking. Fat dies every 7 to 10 years, the rate at which a stem cell would be required to work, otherwise it lies dormant. Conceivably, a generally healthy 60 year-old patient has only required their ADSCs to “work” maybe 9 or 10 times in their life. As a single stem cell is capable of producing 1031 stem cells, only having to work 9 or 10 times renders this cell pretty young and healthy, hence why ADSCs show strong viability numbers in patients ranging from 10 to 90 years old.
There could be times where allogeneic sources are vital, such as end of life scenarios, or times when the patient is too frail for surgery and requires cell therapy. But while off the shelf stem cells might be appealing for now for all general cases, please take caution before considering giving them to your patients.