There are many ways to classify different stem cells. These differences include yours versus someone else’s cells. Another distinct in a clinical sense is what we call an autologous vs allogeneic stem cell transplant.
This post is focused on the difference between allogeneic (someone else’s cells) and autologous (your own) stem cell injections. As a stem cell biologist I have been using stem cells of various kinds for about 20 years. My lab at UC Davis School of Medicine has published many papers in this area.
If you want to learn more about the different core kinds of stem cell types, see my post on multipotent, pluripotent, and totipotent stem cells.
Autologous versus allogeneic stem cells: definitions
What is the definition of autologous stem cells? Autologous comes from the root “auto” meaning self. Therefore, any time you see a reference to autologous stem cells, it is talking about the patient’s own cells. An example of an autologous stem cell transplant would be taking bone marrow cells from your hip and injecting them somewhere else in your body. Everything happens in the same person in this case.
What is the definition of allogeneic stem cells? The term “allogeneic stem cells” means that the cells are coming from someone else. That other person could be an adult or could come from placenta or umbilical cord. Note that birth-related tissues like placenta, amnion, and umbilical cord come from a baby, not from the mother. Most often these tissues are discarded, but more recently sometimes cells from them are isolated in a lab and studied or used in clinical trials. They are often sold these days as some kind of panacea as well at unproven stem cell clinics.
Autologous vs allogeneic: clinical implications
In general, autologous stem cells have several advantages.
A match. First, since they are the patient’s own cells, they have little to no risk of being rejected by the immune system. This means that an autologous stem cell transplant is more likely to “take”, which we scientists call “engraft”. In other words, autologous cells are likely to stick around longer than allogeneic after a transplant. Of course, this depends on the context. For instance, autologous fat stem cells injected into the bloodstream by IV seem to be rapidly removed by the body. This happens even though the cells are the patient’s own material. As a result, this frequent offering sold by unproven stem cell clinics is unlikely to do anything helpful.
Autologous vs allogeneic safety. Also, autologous stem cell transplants are generally going to be safer than allogeneic because of the matching factor, but not always. Autologous does not equal safe. There have been people blinded or have other problems after getting injections of their own fat stem cell cells and possibly their own bone marrow cells into their eyes.
Allogeneic stem cell transplant advantages. There are ways that allogeneic transplants could be better, but they are somewhat less clear or more hypothetical.
One potential clear advantage is cost. As more stem cell transplants are approved in the coming decade by regulators like the FDA, allogeneic therapies may have lower price tags. This is because they can be expanded to a great scale ahead of time and frozen for use on demand. In contrast, many autologous therapies need to be made anew for each patient. It also means that another possible advantage of allogeneic cell therapies is the quick turnaround time for treating the patient. For more on stem cell treatment cost see this 2021 post with comprehensive polling data from several years.
A disadvantage to allogeneic cells is that they are foreign to the patient’s body. This means that there is a high risk of the cells, once injected, simply being obliterated by the patient’s immune system. Some allogeneic stem cells may have the ability to fly under the radar of the immune system, but this is still being studied and debated.
Bone marrow transplant versus other offerings
Finally, it is crucial to know that bone marrow transplants, whether autologous or allogeneic, are fundamentally different than what is being offered at stem cell clinics.
Bone marrow transplants and the related therapy of hematopoietic stem cell transplants (including cord blood stem cells), are proven to work to help patients have a better chance to overcome blood cancers in combination with chemotherapy. These cells may have some utility in treating certain immune disorders as well, which is exciting. It is sobering, though, how severe these treatments can be overall because of the chemotherapy. However, that is necessary to have the best chance to wipe out all the cancer cells.
With that context, keep in mind that bone marrow or cord blood stem cells are unproven to do anything. Not yet at least.
In the end, as to the question of autologous vs allogeneic, it all depends on the circumstances.
References
- Autologous stem cell transplant resource, Mayo Clinic.
- Stem cell transplant fact sheet, National Cancer Institute.
- Mesenchymal stem cells: immune evasive, not immune privileged, Nature Biotechnology.
Disclaimer: this post is not medical advice. Always consult your physician before making health-related decisions.
There are multiple projects underway to develop hypo-immune stem cells, such as those of Sana Biotech. I don’t know how likely is it that a configuration (of genetic modifications) can be found to both avoid being recognized as non-self, but these would surely be the holy grail for therapies using stem cell derived tissues.
Dear Dr. Knopfler,
“Fat Stem Cells” are not a technical term. If we are to have a scientific discourse, we should be speaking in technical terms because faulty or inaccurate wording can cause misconception and misunderstanding. There already exists so much confusion in this field that I stress the importance of accurate terminology (particularly from someone who has built the most read stem cell blog on the planet).
When you use the words “fat stem cells”, I assume you mean adipose-derived stem cells as opposed to stem cells that can differentiate into fat. Adipose-derived stem cells are also defined in many ways. Are you talking about SVF or actually isolated cells that have gone through some sort of separation step? It is also important to know whether they have been properly identified because by your definition, you may end up with more adipocytes or blood cells than actual stem cells. Do you see the problem?
When you say “…autologous fat stem cells injected into the bloodstream by IV seem to be rapidly removed by the body” may be an accurate statement depending on what you are referring to. However, as someone in the field, this statement is extremely vague and unscientific. You further go on to say “Autologous does not equal safe. There have been people blinded or have other problems after getting injections of the own fat stem cells and possibly their own bone marrow into their eyes”. You have made a claim about autologous safety and referring to an instance where stem cells may or may not have been injected (we don’t know because they did not identify the cells nor the concentration). What we do know from those case studies is that PRP was generated and the pellet added to that. This concoction, whatever it contained (and whether it was even sterile) is what posed the safety issue rather than it being an autologous product issue.
There is no shortage of bad “stem cell” work being done. The field needs to do a better job communicating the science so that we don’t inadvertently or indirectly hinder great work from being done. Amazing advances in the stem cell world are coming to light and it’s more important than ever to accurately report the facts and not let our preconceived notions, opinions and assumptions drive the conversations.
@stemcelllady,
I get your points, but there are challenges in this space as to the best way to communicate.
This website, for instance, has a very heterogenous group of readers including many scientists but also many in the lay public who don’t know many of the words we use daily. Phrases like “adipose-derived stem cells” or “stromal vascular fraction” can be confusing. Hence the use of “fat stem cells” at times. I do have an explainer on SVF and another on PRP. I’m adding more of these explainer kind of resources all the time.
You’re right about us not knowing all the facts related to the adverse events at stem cell clinics using autologous preparations and other such firms, but my point was that autologous does not equal something being safe. That statements is well-supported by what we do know. I also highlighted the numerous advantages of autologous approaches including likely better safety profiles in general.
I appreciate your passion for this topic.
Any studies concerning hemorrhagic strokes on the horizon