title: Single-tube test for autoantibodies to glutamic acid decarboxylase and proinsulin as first-line screening for autoimmunity in adult-onset diabetic patients.
abstract: The aim of this work was develop a new combined radioligand-binding assay (RBA-combi) for the rapid and simultaneous determination of two autoimmunity markers, GADA and PAA, known to be differentially distributed in young and in some adult diabetic patients. The methodology was applied to sera from 85 young type 1 and 98 adult-onset diabetic patients with different marker profiles and insulin requirements, and to 53 normal control sera. Among type 1 diabetes sera used as autoimmunity controls, 100% of those with at least one positive marker by single methods and 17.7% of those with double negative markers were positive by RBA-combi (RBA-combi+). Among sera from adult-onset diabetes, 100% of those PAA+ (GADA+ or GADA-), 92.3% of GADA+/PAA-, and 1.3% of GADA-/PAA- were RBA-combi+. In conclusion, the new RBA-combi allowed the simultaneous detection of GADA and PAA markers with acceptable performance. Moreover, 16 out of 18 (88.9%) of adult patients RBA-combi+ evolved to insulin requirement, suggesting that this test is a valuable tool for assessing autoimmune processes associated to future impairment of insulin secretion.
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires, and Humoral Immunity Institute, National Research Council, Argentina.
authors.forename: Silvina N
authors.initials: SN
authors.lastname: Valdez
authors.forename: Anabel
authors.initials: A
authors.lastname: Villalba
authors.forename: Ruben F
authors.initials: RF
authors.lastname: Iacono
authors.forename: Edgardo
authors.initials: E
authors.lastname: Poskus
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D001327:Autoimmune Diseases / Q000150:complications / Q000175:diagnosis* / Q000201:enzymology / Q000276:immunology; D015551:Autoimmunity / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000175:diagnosis* / Q000201:enzymology / Q000276:immunology*; D005260:Female; D005968:Glutamate Decarboxylase / Q000097:blood / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D011384:Proinsulin / Q000097:blood / Q000276:immunology*; D011869:Radioligand Assay
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D011384:Proinsulin; D005968:Glutamate Decarboxylase