Islet Cell Antibodies Identify Latent Type I Diabetes in Patients Aged 35–75 Years at Diagnosis

  1. Deborah Doniach
  1. Fourth Department of Medicine, Helsinki University Central Hospital Helsinki, Finland Department of Immunology, Middlesex Hospital Medical School London, United Kingdom
  1. Address reprint requests to G. F. Bottazzo, Department of Immunology, Arthur Stanley House, The Middlesex Hospital Medical School, 40–50 Tottenham Street, London W1P 9PG, United Kingdom.

Abstract

One hundred fifty-four selected patients with nonketotic diabetes diagnosed between the ages of 35 and 75 yr and treated with diet or oral hypoglycemie agents for at least 1 yr were investigated for parameters of glycemie control (weight loss, blood glucose, and glycosylated hemoglobin), islet cell function (fasting and glucagon-stimulated C-peptide responses), and immunologie markers of insulitis (total ICA and CF-ICA) or autoimmunity (thyroid and gastric antibodies). These parameters were all repeated in 9 of 22 ICA-positive patients after a 2-yr follow-up and correlated with secondary drug failure. The antibody tests were also done on 51 nondiabetic controls matched for age and body weight.

The 22 (14%) diabetic subjects having positive islet cell antibodies (ICA) included more women than men with a shorter duration of symptoms, lower body weight, more associated thyroid autoimmunity, and a tendency to have more type I diabetes in their families, although glycemic control, age at onset, and family history of type II diabetes were the same as in the 132 ICA-negative cases.

Patients with ICA had lower initial C-peptide levels and showed little rise after glucagon stimulation. Beta cell function deteriorated significantly during the 2-yr follow-up in 9 of 22 positive patients and more ICA-positive patients required insulin. It is suggested that these latent type I diabetic patients are characterized by persistent ICA, progressive loss of beta cells, and a high frequency of thyrogastric autoimmunity. The determination of ICA may be of clinical value in the diagnosis and treatment of nonketotic diabetes with onset in later life.

  • Received March 21, 1985.
  • Revision received September 3, 1985.
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