title: Novel Phospholipid-Protein Conjugates Allow Improved Detection of Antibodies in Patients with Autoimmune Diseases.
abstract: Reliable measurement of clinically relevant autoimmune antibodies toward phospholipid-protein conjugates is highly desirable in research and clinical assays. To date, the development in this field has been limited to the use of natural heterogeneous antigens. However, this approach does not take structural features of biologically active antigens into account and leads to low reliability and poor scientific test value. Here we describe novel phospholipid-protein conjugates for specific detection of human autoimmune antibodies. Our synthetic approach includes mild oxidation of synthetic phospholipid cardiolipin, and as the last step, coupling of the product with azide-containing linker and copper-catalyzed click chemistry with β2-glycoprotein I and prothrombin. To prove utility of the product antigens, we used enzyme-linked immunosorbent assay and three cohorts of samples obtained from patients in Denmark (n = 34) and the USA (n = 27 and n = 14). Afterwards we analyzed correlation of the obtained autoantibody titers with clinical parameters for each patient. Our results prove that using novel antigens clinically relevant autoantibodies can be detected with high repeatability, sensitivity and specificity. Unlike previously used antigens the obtained autoantibody titers strongly correlate with high disease activity and in particular, with arthritis, renal involvement, anti-Smith antibodies and high lymphocyte count. Importantly, chemical composition of antigens has a strong influence on the correlation of detected autoantibodies with disease activity and manifestations. This confirms the crucial importance of antigens' composition on research and diagnostic assays, and opens up exciting perspectives for synthetic antigens in future studies of autoimmunity.
authors.affiliation: Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark.
authors.forename: Simone V
authors.initials: SV
authors.lastname: Samuelsen
authors.affiliation: Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark.
authors.forename: Arindam
authors.initials: A
authors.lastname: Maity
authors.affiliation: Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark.
authors.forename: Mads
authors.initials: M
authors.lastname: Nybo
authors.affiliation: Department of Pediatrics, Program in Immunology, Stanford University, Stanford, California, United States of America.
authors.forename: Claudia
authors.initials: C
authors.lastname: Macaubas
authors.affiliation: Department of Business and Economics, University of Southern Denmark, Odense, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Lønstrup
authors.affiliation: Department of Pediatrics, Program in Immunology, Stanford University, Stanford, California, United States of America.
authors.forename: Imelda M
authors.initials: IM
authors.lastname: Balboni
authors.affiliation: Department of Pediatrics, Program in Immunology, Stanford University, Stanford, California, United States of America.
authors.forename: Elizabeth D
authors.initials: ED
authors.lastname: Mellins
authors.affiliation: Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark.
authors.forename: Kira
authors.initials: K
authors.lastname: Astakhova
mesh_terms: D000293:Adolescent; D017152:Antibodies, Antiphospholipid / Q000032:analysis* / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis* / Q000276:immunology; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000276:immunology; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D017152:Antibodies, Antiphospholipid; D001323:Autoantibodies