Dr Reijonen’s research projects aim at improving the understanding of the characteristics of the immune cell repertoire which is responsible for the destruction of insulin-producing beta cells, and regulation of this process. The focus of her research is on the following areas:
1. Profiling of islet specific immune response in Type 1 diabetes. The goal is to identify T lymphocytes relevant for the progression to Ttype 1 diabetes and understanding the characteristics of these cells. Utilization of MHC class II tetramers makes it possible to probe the T lymphocyte compartment for specificity, frequency and phenotype. Tetramer-based assays are used for immunomonitoring of the autoimmunity in the individuals who are at risk but have not progressed to Type 1 diabetes yet. Also, specimens from subjects participating in clinical trials aiming at the intervention of diabetes will be investigated. Accurate measures of changes in the T cell responses are needed in these trials to determine the effect of immunomodulatory therapies. Another goal in this project is to discover new relevant determinants from different islet cell proteins, which will further improve the sensitivity of disease prediction and immunomonitoring.
2. Recurrence of autoimmunity in Type 1 diabetes patients with kidney-pancreas transplants. Future developments of this research include strategies to prevent recurrence of autoimmunity and destruction of the transplanted islets in Type 1 diabetes patients who have received simultaneous kidney-pancreas (SPK) transplants. This follow-up study will define the relationship between islet-specific autoantibodies, autoreactive T lymphocytes, inflammation of the islets and insulin secretion in these patients. Methodological advances such as tetramer-based assays offer an unprecedented opportunity to characterize specificity and the functional status of autoreactive T lymphocytes in blood and occasional biopsy tissues when available. These studies will provide critical information about the immunological mechanisms regulating recurrence of autoimmunity and islet destruction in SPK recipients and assess the predictive value of relevant laboratory tests that may be applied in the pancreas transplant setting.
3. MHC class II mediated protective mechanisms in Type 1 diabetes. Some MHC class II genes confer dominant protection from Type 1 diabetes. In this project characteristics and function of T lymphocytes in individuals who carry both the diabetes-predisposing and protective MHC class II molecules will be investigated. The goal is to gain greater insight into the mechanisms of disease resistance mediated by protective MHC class II responses.
Helena Reijonen, PhD
Kelly Geubtner, Research Technician
Chris Mendez, Research Technician