title: Importance of persistent cellular and humoral immune changes before diabetes develops: prospective study of identical twins.
abstract: OBJECTIVE
  To determine the pattern of cellular and humoral immune changes associated with insulin dependent diabetes before diabetes develops.
  
  
  METHODS
  Prospective study over 10 years of 25 non-diabetic identical twins of patients with insulin dependent diabetes. The non-diabetic twins were followed up either till they developed diabetes or to the end of the study.
  
  
  METHODS
  Teaching hospital.
  
  
  METHODS
  25 non-diabetic identical cotwins of patients with diabetes; 46 controls of the same sex and similar age tested over the same period. Of the 25 twins (total follow up 144 patient years), 10 developed diabetes (prediabetic twins); the remainder were followed up for a mean of 7.7 years.
  
  
  METHODS
  Results of glucose tolerance tests or fasting blood glucose concentrations at each sample point. Measurements of activated T lymphocytes, expressing the HLA-DR antigen, islet cell antibodies, and insulin autoantibodies in samples.
  
  
  RESULTS
  All 10 prediabetic twins had both cellular and humoral changes initially and in most samples before diabetes was diagnosed (activated T lymphocytes in 39/40, islet cell antibodies in 45/47, and insulin autoantibodies to islet cells and insulin were detected infrequently (in 8/54, 6/69, and 0/69 samples, respectively). The combination of cellular and humoral (islet cell antibodies or insulin autoantibodies) immune changes were detected in all 10 of the prediabetic twins but in only one of the 15 non-diabetic twins (P < 0.001). The positive predictive value in this cohort of increased percentages of activated T cells and the presence of antibodies to islet cells or insulin on two consecutive occasions was 100%.
  
  
  CONCLUSIONS
  Most of the twins had cellular or humoral immune changes at some stage. A combination of cellular and humoral immune changes and their tendency to persist is highly predictive of insulin dependent diabetes and distinguishes twins who develop diabetes from those who do not.
authors.affiliation: Department of Diabetes and Metabolism, St Bartholomew's Hospital, London.
authors.forename: R Y
authors.initials: RY
authors.lastname: Tun
authors.forename: M
authors.initials: M
authors.lastname: Peakman
authors.forename: L
authors.initials: L
authors.lastname: Alviggi
authors.forename: M J
authors.initials: MJ
authors.lastname: Hussain
authors.forename: S S
authors.initials: SS
authors.lastname: Lo
authors.forename: M
authors.initials: M
authors.lastname: Shattock
authors.forename: D A
authors.initials: DA
authors.lastname: Pyke
authors.forename: G F
authors.initials: GF
authors.lastname: Bottazzo
authors.forename: D
authors.initials: D
authors.lastname: Vergani
authors.forename: R D
authors.initials: RD
authors.lastname: Leslie
mesh_terms: D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000032:analysis; D000917:Antibody Formation; D001786:Blood Glucose / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000276:immunology*; D004200:Diseases in Twins; D005260:Female; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007111:Immunity, Cellular; D007328:Insulin / Q000276:immunology; D007515:Islets of Langerhans / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D011446:Prospective Studies; D013601:T-Lymphocytes / Q000276:immunology; D014430:Twins, Monozygotic
chemical_list: D000906:Antibodies; D001786:Blood Glucose; D006684:HLA-DR Antigens; D007328:Insulin