The human immune system is highly responsive yet tightly controlled – it must be able to respond appropriately to new threats like infections and viruses, but at the same time must not overreact and attack the host, causing autoimmunity for example. These immune responses are normally controlled by T regulatory cells, and studies have shown that when they malfunction or when their numbers change, the immune response is impaired. This project looked at identifying genes involved in the immune response with the goal of finding ways to tune the immune response up or down in individual patients. The project successfully generated a gene expression profile that accurately differentiates human T regulatory cells regardless of their status of activation. The utility of this gene signature as a biomarker of disease status in Type 1 diabetes is being investigated using follow-on funding.