Brooks-Worrell B.M.,University of Washington |
Brooks-Worrell B.M.,DVA Puget Sound Health Care System |
Brooks-Worrell B.M.,Seattle Biomedical Research Institute |
Brooks-Worrell B.M.,Diabetes Endocrinology Research Center |
And 8 more authors.
Diabetes Care | Year: 2011
OBJECTIVE - Islet autoimmunity has long been recognized in the pathogenesis of type 1 diabetes and is becoming increasingly acknowledged as a component in the pathogenesis of type 2 diabetes. Islet reactive T cells and autoantibodies have been demonstrated in type 1 diabetes, whereas islet autoimmunity in type 2 diabetes has been limited to islet autoantibodies. In this study, we investigated whether islet reactive T cells might also be present in type 2 diabetic patients and how islet reactive T cells correlate with β-cell function. RESEARCH DESIGN AND METHODS - Adult phenotypic type 2 diabetic patients (n=36) were screened for islet reactive T-cell responses using cellular immunoblotting and five islet autoantibodies (islet cell antibody, GADA, insulin autoantibody, insulinoma-associated protein-2 autoantibody, and zinc transporter autoantibody). RESULTS - We identified four subgroups of adult phenotypic type 2 diabetic patients based on their immunological status (Ab -T-, Ab+T-, Ab-T +, and Ab+T+). The Ab-T+ type 2 diabetic patients demonstrated T-cell responses similar to those of the Ab+T+ type 2 diabetic patients. Data were adjusted for BMI, insulin resistance, and duration of diabetes. Significant differences (P < 0.02) were observed among groups for fasting and glucagon-stimulated C-peptide responses. T-cell responses to islet proteins were also demonstrated to fluctuate less than autoantibody responses. CONCLUSIONS - We have identified a group of adult autoimmune phenotypic type 2 diabetic patients who are Ab -T+ and thus would not be detected using autoantibody testing alone. We conclude that islet autoimmunity may be more prevalent in adult phenotypic type 2 diabetic patients than previously estimated. © 2011 by the American Diabetes Association.