title: IA-2 combined epitope assay: a new, highly sensitive approach to evaluate IA-2 humoral autoimmunity in type 1 diabetes.
abstract: Islet tyrosine phosphatase 2 (IA-2) is one of the major autoantigens in type 1 diabetes. The aim of this work was to evaluate which IA-2 construct(s) among those usually employed has the highest sensitivity and specificity for detecting IA-2 autoantibodies in autoimmune diabetes and whether the combination of different IA-2 constructs into a single assay allows the detection of immunoreactivities otherwise not detectable by a single construct. For this purpose, we tested the single immunoreactivities of IA-2 FL(aa 1-979), IA-2(BDC)(aa 256-556:630-979), IA-2 IC(aa 605-979), IA-2(aa 256-760), IA-2(aa 761-928), and of 7 combinations of these fragments in the sera of 203 newly diagnosed type 1 diabetic patient (DM: 109 males,94 females, mean age 12.9 +/- 7.5 years) and 43 prediabetic subject (PDM: 20 males, 23 females, mean age 10.3 +/- 6.0 years) sera. IA-2 IC was the single construct that showed the highest sensitivity and specificity both in DM and PDM subjects; however, all of the other IA-2 constructs investigated detected additional immunoreactivities with respect to it. The combined use into the same assay of IA-2 IC, IA-2 FL, and IA-2 (256-760) constructs allowed detection of IA-2 Abs in additional 13.3% DM and 30.4% PDM subjects compared to the single IA-2 IC construct, suggesting this methodology as a new, highly sensitive approach to the study of IA-2 autoimmunity in type 1 diabetes.
authors.affiliation: Department of Medical Sciences, Endocrinology, University of Rome La Sapienza, Italy. claudio.tiberti@uniroma1.it
authors.forename: Claudio
authors.initials: C
authors.lastname: Tiberti
authors.forename: Antonella
authors.initials: A
authors.lastname: Verrienti
authors.forename: Benedetta
authors.initials: B
authors.lastname: Fiore
authors.forename: Liping
authors.initials: L
authors.lastname: Yu
authors.forename: George S
authors.initials: GS
authors.lastname: Eisenbarth
authors.forename: Francesco
authors.initials: F
authors.lastname: Dotta
authors.forename: Umberto
authors.initials: U
authors.lastname: Di Mario
mesh_terms: D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D001323:Autoantibodies / Q000276:immunology; D015551:Autoimmunity; D001483:Base Sequence; D015415:Biomarkers / Q000097:blood; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis* / Q000235:genetics / Q000276:immunology; D000939:Epitopes / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D054648:Protein Phosphatase 2; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000032:analysis / Q000235:genetics / Q000276:immunology*; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8; D012680:Sensitivity and Specificity
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D000939:Epitopes; D008565:Membrane Proteins; D054648:Protein Phosphatase 2; C102889:PTPRN2 protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8