Use naturally immune privileged cells in islet transplantation
Parts of hair follicles exhibit “immune privilege” due to the secretion of immuno-regulatory factors and a lack of expression of the human leukocyte antigen (HLA proteins) on their cell surface. It is the HLA antigens that are recognized by the immune system and lead to organ transplant rejection. Because these unusual hair follicle cells do not have HLA antigens on their surface, they are not “seen” by the immune system. Unlike most cells and organs, the hair follicle cells are not rejected when transplanted from one person to another. These hair follicle cells also actively secrete factors that suppress local immune system activity. We propose to use these cells, with their natural non- or low-immunity, to locally protect transplanted islets. We will “coat” islets with the hair follicle cells to provide a protective shield for the islets against rejection by the transplant recipient’s immune system. After transplantation, the hair follicle cells will hide the islet cells from the immune system but allow them to function and control blood sugar levels. If this approach is successful, it will provide a simple way to transplant islets to people who have type I diabetes. It should be a permanent treatment that will avoid the need for using immunosuppressive drugs and will mean that diabetic patients no longer need use insulin injections to control their blood sugar levels.