title: Persistent T cell anergy in human type 1 diabetes.
abstract: An anergic phenotype has been observed in nonobese diabetic (NOD) mice and some autoreactive T cells from patients with type I diabetes. To better understand this phenomenon, we measured T cell proliferative responses to 10 diabetes-associated and up to 9 control Ags/peptides in 148 new diabetic children, 51 age- and MHC (DQ)-matched siblings (sibs), 31 patients with longstanding diabetes, and 40 healthy controls. Most (78-91%) patient and sib responses to glutamate decarboxylase of 65 kDa (GAD65), islet cell cytoplasmic autoantibody (ICA) 69, diabetes-associated T cell epitopes in ICA69 (Tep69), and heat shock protein (Hsp) 60 involved anergic T cells that required exogenous IL-2 to proliferate. Responses to proinsulin, IA-2 (and tetanus toxoid) required no IL-2 and generated sufficient cytokine to rescue anergic T cell responses. Most new patients (85%) had autoreactive T cells, three quarters targeting more than half of the diabetes Ags. Only 7.8% of the sibs and none of the controls had such multiple T cell autoreactivities, which thus characterize overt disease. Multiple anergic and nonanergic T cell autoreactivities were sustained during 2 yr follow-up after onset and in patients with longstanding (3-26 yr) diabetes. Activated patient T cells survived severe IL-2 deprivation, requiring 20-100 times less IL-2 than normal T cells to escape apoptosis. Diabetic T cell anergy thus persists for decades and is Ag and host specific but not related to disease course. Rescue by IL-2 from bystander T cells and high resistance to apoptosis may contribute to this persistence. These data explain some of the difficulties in the routine detection of disease-associated T cells, and they emphasize challenges for immunotherapy and islet transplantation.
authors.affiliation: Department of Pediatrics, University of Toronto, The Hospital For Sick Children, Research Institute, Toronto, Ontario, Canada. hmdosch@sickkids.on.ca
authors.forename: H
authors.initials: H
authors.lastname: Dosch
authors.forename: R K
authors.initials: RK
authors.lastname: Cheung
authors.forename: W
authors.initials: W
authors.lastname: Karges
authors.forename: M
authors.initials: M
authors.lastname: Pietropaolo
authors.forename: D J
authors.initials: DJ
authors.lastname: Becker
mesh_terms: D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D001323:Autoantibodies / Q000096:biosynthesis; D002648:Child; D002675:Child, Preschool; D017635:Clonal Anergy / Q000276:immunology*; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007223:Infant; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D012307:Risk Factors; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors
chemical_list: D001323:Autoantibodies; D007376:Interleukin-2; D013936:Thymidine