title: Characterization of insulin antibodies by Surface Plasmon Resonance in two clinical cases: brittle diabetes and insulin autoimmune syndrome.
abstract: In this study, the characterization of insulin (auto)antibodies has been described, mainly in terms of concentration (q), affinity (Ka) and Ig (sub)isotypes by Surface Plasmon Resonance (SPR) in two particular clinical cases of individuals with severe episodes of impaired glycemia. Subject 1 suffers from brittle diabetes associated with circulating insulin antibodies (IA) due to insulin treatment. Subject 2 has insulin autoantibodies (IAA) associated with hypoglycemia in spite of not being diabetic and not having ever received exogenous insulin therapy. After conventional screening for IA/IAA by radioligand binding assay (RBA), we further characterized IA/IAA in sera of both patients in terms of concentration (q), affinity (Ka) and Ig (sub)isotypes by means of SPR technology. In both cases, q values were higher and Ka values were lower than those obtained in type 1 diabetic patients, suggesting that IA/IAA:insulin immunocomplexes could be responsible for the uncontrolled glycemia. Moreover, subject 1 had a predominat IgG1 response and subject 2 had an IgG3 response. In conclusion, SPR technology is useful for the complete characterization of IA/IAA which can be used in special cases where the simple positive/negative determination is not enough to achieve a detailed description of the disease fisiopathology.
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires (UBA) and Prof. Ricardo A. Margni Humoral Immunity Institute (IDEHU), National Research Council (CONICET)-UBA, Buenos Aires, Argentina.
authors.forename: Aldana
authors.initials: A
authors.lastname: Trabucchi
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires (UBA) and Prof. Ricardo A. Margni Humoral Immunity Institute (IDEHU), National Research Council (CONICET)-UBA, Buenos Aires, Argentina.
authors.forename: Ruben F
authors.initials: RF
authors.lastname: Iacono
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires (UBA) and Prof. Ricardo A. Margni Humoral Immunity Institute (IDEHU), National Research Council (CONICET)-UBA, Buenos Aires, Argentina.
authors.forename: Luciano L
authors.initials: LL
authors.lastname: Guerra
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires (UBA) and Prof. Ricardo A. Margni Humoral Immunity Institute (IDEHU), National Research Council (CONICET)-UBA, Buenos Aires, Argentina.
authors.forename: Natalia I
authors.initials: NI
authors.lastname: Faccinetti
authors.affiliation: Nutrition Service, J. P. Garrahan National Pediatrics Hospital, Buenos Aires, Argentina.
authors.forename: Andrea G
authors.initials: AG
authors.lastname: Krochik
authors.affiliation: Pedriatrics Service, Private Community Hospital, Mar del Plata, Argentina.
authors.forename: María C
authors.initials: MC
authors.lastname: Arriazu
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires (UBA) and Prof. Ricardo A. Margni Humoral Immunity Institute (IDEHU), National Research Council (CONICET)-UBA, Buenos Aires, Argentina.
authors.forename: Edgardo
authors.initials: E
authors.lastname: Poskus
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires (UBA) and Prof. Ricardo A. Margni Humoral Immunity Institute (IDEHU), National Research Council (CONICET)-UBA, Buenos Aires, Argentina.
authors.forename: Silvina N
authors.initials: SN
authors.lastname: Valdez
mesh_terms: D000293:Adolescent; D000368:Aged; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000276:immunology*; D005260:Female; D006801:Humans; D007223:Infant; D007328:Insulin / Q000276:immunology*; D007330:Insulin Antibodies / Q000097:blood*; D008297:Male; D020349:Surface Plasmon Resonance
chemical_list: D001323:Autoantibodies; D007328:Insulin; D007330:Insulin Antibodies