title: Is latent autoimmune diabetes in adults distinct from type 1 diabetes or just type 1 diabetes at an older age?
abstract: Diabetes is classified clinically into two types: type 1 and type 2 diabetes. Type 1 diabetes is an autoimmune diabetes, whereas, in contrast, type 2 diabetes is nonautoimmune. However, there is a group of phenotypic adult type 2 diabetic patients ( approximately 10%) who have islet autoantibodies similar to type 1 diabetes. These patients are said to have latent autoimmune diabetes in adults (LADA) or type 1.5 diabetes. T-cells reacting with islet proteins have been demonstrated in type 1 and type 1.5 diabetic patients. In contrast, classic autoantibody-negative type 2 diabetic patients are also negative for T-cell responses to islet proteins. Therefore, we questioned whether type 1 and type 1.5 diabetes are similar or different autoimmune diseases. We have investigated the immunological and metabolic differences between type 1, type 1.5, and classic type 2 diabetic patients. We have identified autoantibody differences, differences in islet proteins recognized by T-cells, and differences in insulin resistance. We have also identified a small group of patients who have T-cells responsive to islet proteins but who are autoantibody negative. These patients appear to be similar to type 1.5 patients in having decreased stimulated C-peptide values. These immunological differences between type 1 and type 1.5 diabetes suggest at least partially distinct disease processes.
authors.affiliation: Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, USA. jpp@u.washington.edu
authors.forename: Jerry P
authors.initials: JP
authors.lastname: Palmer
authors.forename: Christiane S
authors.initials: CS
authors.lastname: Hampe
authors.forename: Harvey
authors.initials: H
authors.lastname: Chiu
authors.forename: Amit
authors.initials: A
authors.lastname: Goel
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Brooks-Worrell
mesh_terms: D000328:Adult; D000367:Age Factors; D001323:Autoantibodies / Q000097:blood*; D015551:Autoimmunity; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000145:classification* / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000145:classification; D007333:Insulin Resistance; D011930:Reaction Time / Q000276:immunology
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G