title: Use of a High-Density Protein Microarray to Identify Autoantibodies in Subjects with Type 2 Diabetes Mellitus and an HLA Background Associated with Reduced Insulin Secretion.
abstract: New biomarkers for type 2 diabetes mellitus (T2DM) may aid diagnosis, drug development or clinical treatment. Evidence is increasing for the adaptive immune system's role in T2DM and suggests the presence of unidentified autoantibodies. While high-density protein microarrays have emerged as a useful technology to identify possible novel autoantigens in autoimmune diseases, its application in T2DM has lagged. In Pima Indians, the HLA haplotype (HLA-DRB1*02) is protective against T2DM and, when studied when they have normal glucose tolerance, subjects with this HLA haplotype have higher insulin secretion compared to those without the protective haplotype. Possible autoantibody biomarkers were identified using microarrays containing 9480 proteins in plasma from Pima Indians with T2DM without the protective haplotype (n = 7) compared with those with normal glucose regulation (NGR) with the protective haplotype (n = 11). A subsequent validation phase involving 45 cases and 45 controls, matched by age, sex and specimen storage time, evaluated 77 proteins. Eleven autoantigens had higher antibody signals among T2DM subjects with the lower insulin-secretion HLA background compared with NGR subjects with the higher insulin-secretion HLA background (p<0.05, adjusted for multiple comparisons). PPARG2 and UBE2M had lowest p-values (adjusted p = 0.023) while PPARG2 and RGS17 had highest case-to-control antibody signal ratios (1.7). A multi-protein classifier involving the 11 autoantigens had sensitivity, specificity, and area under the receiver operating characteristics curve of 0.73, 0.80, and 0.83 (95% CI 0.74-0.91, p = 3.4x10-8), respectively. This study identified 11 novel autoantigens which were associated with T2DM and an HLA background associated with reduced insulin secretion. While further studies are needed to distinguish whether these antibodies are associated with insulin secretion via the HLA background, T2DM more broadly, or a combination of the two, this study may aid the search for autoantibody biomarkers by narrowing the list of protein targets.
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, United States of America.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Chang
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, United States of America.
authors.forename: Paolo
authors.initials: P
authors.lastname: Piaggi
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, United States of America.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Hanson
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, United States of America.
authors.forename: William C
authors.initials: WC
authors.lastname: Knowler
authors.affiliation: Life Technologies, Carlsbad, California, United States of America.
authors.forename: John
authors.initials: J
authors.lastname: Bucci
authors.affiliation: Life Technologies, Carlsbad, California, United States of America.
authors.forename: Guene
authors.initials: G
authors.lastname: Thio
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, United States of America.
authors.forename: Maximilian G
authors.initials: MG
authors.lastname: Hohenadel
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, United States of America.
authors.forename: Clifton
authors.initials: C
authors.lastname: Bogardus
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona, United States of America.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Krakoff
mesh_terms: D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000276:immunology*; D015415:Biomarkers; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism*; D005260:Female; D006680:HLA Antigens / Q000235:genetics* / Q000378:metabolism; D006239:Haplotypes; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged; D047495:PPAR gamma / Q000378:metabolism; D040081:Protein Array Analysis; D012680:Sensitivity and Specificity; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D006680:HLA Antigens; D007328:Insulin; D047495:PPAR gamma; D044763:Ubiquitin-Conjugating Enzymes; C000596156:UBE2M protein, human