Even our graduate students know that!!! Here at the Panama College of Cell Science, we try to teach students to be specific regarding their use of terms. Even though our three year online PhD biology program is delivered online, yet, we try to approach stem cell science in a scholarly manner.
Lately we have noticed a new term for stem cells bandied about in the scientific literature: “autologous embryonic stem cell”. This term is being used to describe Induced Pluripotent Stem Cells.
IPSC’s are artificially created by taking an adult cell, such as a skin cell, and forcing that cell, by way of viral infection, use of gene insertion or otherwise, to become pluripotent, with much the same properties as an embryonic stem cell, yet without being derived from a human embryo. Early on, this exciting development was thought to be a mechanism whereby patient specific embryonic stem cells (or more appropriately, patient specific pluripotent stem cells) could be created that would match the patient immunologically and not be rejected as “foreign” by the patient’s immune system.
Although the original idea has proven flawed in that such cells are immediately rejected by the immune system of the donor, some scientists apparently are trying by terminology to suggest that such iPSC’s are going to be really valuable in therapy. They have started to use the term “autologous embryonic stem cells”. While yes, it is true that such stem cells are derived from the cell of a particular patient, the use of the term “autologous” is totally inappropriate. “Autologous” is a term that has been aligned for over 50 years as an immunological term. Autologous tissue does not cause an immune response and is not rejected by a patient.
For example, consider an autologous bone marrow transplant, wherein a patient’s bone marrow is harvested prior to chemotherapy, and then reintroduced back into the patient with no negative immunological consequence. Or autologous adult stem cell therapy wherein adult stem cells are taken from a patient, and reintroduced into the patient at another site with no immunological consequence…i.e. No immune rejection.
Induced pluripotent stem cells are not “autologous” as that word has come to be understood and used based on immunological principles and observations. And consequently there is no such thing as an “autologous embryonic stem cell”, except perhaps in the dreams and hopes of some scientists.
No one could detail this better than one of our own graduate students in our PhD stem cell program, commenting on an exam about the term, “autologous embryonic stem cell”:
“This is a term fraudulently used to describe patient specific pluripotent cells. This description is based on the assumption that embryonic stem cells derived by somatic-cell nuclear transfer or reprogramming of adult somatic cells to a pluripotent state can provide human-leukocyte-antigen-matched cells, which may be transplanted without the need for immunosuppressive treatment as in autologous therapy. Zhao et al have shown that syngeneic iPSCs induced an immune response leading to tumour regression and immune rejection, suggesting that iPSC may not be immune privileged as previously thought but his syngeneic transplantation model was criticized as not being truly autologous but even at that iPSC’s have also been shown to express wholly different genes and surface markers from the adult cell from which they are derived so they cannot be described as patient specific much less autologous as claimed because the different gene and cell surface markers are very much likely to illicit immunological reaction contrary to a true autologous transplant where no immune reaction is expected.” [Graduate student Paul Faduola].