New Era in Immunotherapy

Organ failure is serious medical condition that is dangerous, expensive, and can lower one’s quality of life. Most often, transplants are the best solution. However, even when available, transplants are not without their own problems. They require an extensive matching process followed by permanent usage of immunosuppressant medication to prevent rejection. These drugs are not only expensive, but they can have quite serious side effects. These include: increased risk of diabetes, increased rate of infection, increased risk of some cancers, and most importantly, damage to the transplanted organ itself.

In response to this, a new protocol has been developed that could make chronic usage of these drugs unnecessary. The basis of this therapy lies in using hematopoietic stem cells from the donor as well as the donated organ. These stem cells differentiate into immune cells that join the patient’s immune system. These cells modulate the response so that T-cells do not attack the new tissue. Initially, this treatment requires the use of radiation and immunosuppresants to prevent an acute response. However, in a short time, the patient can be weaned of these drugs.

Results have been very promising. While this protocol is not ready for widespread usage, it has been demonstrated to work in multiple studies. Also, it is quite affordable at a cost of $40,000 per year. While this is higher than the $10,000-15,000 spent on current medication, the outcomes are much better for the price. Finally, this treatment could even increase the longevity of implanted organs by reducing need for cadaver organs (for example a kidney from a living donor can last twice as long as one from a dead donor).

While more medical than related to bioengineering, I found this article fascinating as it highlights one of the less known aspects of the immune system, regulatory T-cells. While destroying self-reactive lymphocytes is the primary method of preventing autoimmunity, regulatory T-cells play an important role. This can be clearly seen in autoimmune diseases such as Type I Diabetes where failure of this system causes the immune system to kill insulin secreting cells in the pancreas. If we could modulate this system, we could reduce/end transplant matching, immunosuppressant drugs, and autoimmune disease. The possibility associated with this breakthrough is why I picked this article to blog about.

Figure 1: Illustration of pathways associated with T-reg cells reducing lymphocyte activation. While not talked about directly in the article, I feel like this picture (also not from the article) helps one better understand the mechanisms behind the protocol.

Article Link: http://yourlife.usatoday.com/health/story/2011-10-06/Stem-cell-therapy-might-help-kidney-transplant-patients/50677570/1

Image Link: http://www.pnas.org/content/101/28/10398/suppl/DC1