title: Exponential increase of glutamic acid decarboxylase (GAD) antibody titer after initiating and stopping insulin in a patient with slowly progressive type 1 diabetes.
abstract: Few articles have described fluctuations in glutamic acid decarboxylase antibody (GADAb) levels after a diagnosis of slowly progressive type 1 diabetes (SPIDDM). Here, we present a case in which GADAb levels exponentially increased after initiating and stopping insulin. A 64-year-old female patient newly diagnosed with SPIDDM was admitted and started multiple daily insulin injections. The patient's GADAb titer was 6.9 U/mL (normal: <1.4 U/mL) and the patient had a type 1 diabetes susceptible HLA class II haplotype known in the Japanese population as: DRB1*04:05-DQB1*04:01. When the patient's "honeymoon period" set in, hypoglycemia was observed and the dose of insulin was reduced. Two months after the diagnosis, 1 unit of insulin glargine/day was being injected and the patient demonstrated good glycemic control. Subsequently, the patient's home doctor recommended that insulin injections be stopped. Three months after the diagnosis, the patient's GADAb titer suddenly increased to 1600 U/mL. The patient's GADAb titer decreased but was still positive (40 U/mL) 36 months after diagnosis. HbA1c levels were maintained below 7%, and oral glucose tolerance tests at 10, 26, and 36 months after diagnosis suggested that the patient had preserved insulin secretion. To the best of our knowledge, this is the first report that describes exponential increases in GADAb after initiating and stopping insulin in a patient with SPIDDM.
authors.affiliation: Department of Endocrinology and Metabolism Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo 105-8470, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nishimura
authors.forename: Kaoru
authors.initials: K
authors.lastname: Nagasawa
authors.forename: Minoru
authors.initials: M
authors.lastname: Okubo
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Yasumichi
authors.initials: Y
authors.lastname: Mori
mesh_terms: D001323:Autoantibodies / Q000097:blood*; D001786:Blood Glucose / Q000032:analysis; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology*; D005215:Fasting; D005260:Female; D020022:Genetic Predisposition to Disease; D005951:Glucose Tolerance Test; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006442:Glycated Hemoglobin / Q000032:analysis; D006239:Haplotypes; D000949:Histocompatibility Antigens Class II / Q000235:genetics; D006801:Humans; D007003:Hypoglycemia / Q000139:chemically induced; D007328:Insulin / Q000008:administration & dosage*; D000069036:Insulin Glargine / Q000008:administration & dosage; D007564:Japan; D008875:Middle Aged
chemical_list: D001323:Autoantibodies; D001786:Blood Glucose; D005968:Glutamate Decarboxylase; D006442:Glycated Hemoglobin; D000949:Histocompatibility Antigens Class II; D007328:Insulin; D000069036:Insulin Glargine