title: Age-specific levels of diabetes-related GAD and IA-2 antibodies in healthy children and adults.
abstract: Glutamic acid decarboxylase (GAD) and tyrosine phosphatase IA-2 antibody levels were measured in 375 healthy children and adults and in 187 children with newly diagnosed type 1 diabetes mellitus (DM). GAD antibody levels were determined by radioimmunoassay, and IA-2 antibody levels by immunoprecipitation. Healthy children had higher GAD antibody levels than adults (p < 0.001). The 98th percentile was 1.60 U/ml in children and 1.16 U/ml in adults. IA-2 antibody levels did not differ between these two cohorts. Children with DM had higher GAD and IA-2 antibody levels than healthy children (p <0.001). Based on receiver operating characteristics (ROC) analysis, elevated levels of these antibodies showed high specificity rates (+/- SE) of 0.968 +/- 0.14 to 1.00 +/- 0.00. The sensitivity ranged between 0.439 +/- 0.037 (both antibodies elevated) and 0.850 +/- 0.027 (at least one antibody elevated). These data emphasize the importance of establishing age-specific reference values for DM-related antibodies in the background population before applying them for screening and intervention studies.
authors.affiliation: Children's Hospital, Otto-Heubner-Centrum, Charité, Humboldt University, Berlin, Germany. olga.kordonouri@charite.de
authors.forename: Olga
authors.initials: O
authors.lastname: Kordonouri
authors.forename: Reinhard
authors.initials: R
authors.lastname: Hartmann
authors.forename: Anette
authors.initials: A
authors.lastname: Grüters-Kieslich
authors.forename: Mikael
authors.initials: M
authors.lastname: Knip
authors.forename: Thomas
authors.initials: T
authors.lastname: Danne
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000097:blood*; D000918:Antibody Specificity; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000201:enzymology*; D005260:Female; D005968:Glutamate Decarboxylase / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D012372:ROC Curve; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8
chemical_list: D000906:Antibodies; C516862:PTPRN protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8; D005968:Glutamate Decarboxylase