title: Evaluation of the reactivity of sera from patients with systemic lupus erythematosus against the human MCP1.
abstract: This study evaluates metaphase chromosome protein 1 (MCP1), a nuclear antigen, as a diagnostic marker for systemic lupus erythematosus (SLE). Reactivity of sera from 114 Portuguese patients with autoimmune rheumatic disease or from healthy blood donors (HBD), against MCP1, produced in bacteria (bact-MCP1) or in its native form (native-MCP1), was determined by immunoblotting. Predictive and discriminative power of MCP1 reactivity for SLE diagnosis in disease-control groups was evaluated by logistic regression, its diagnostic value determined by receiver-operating characteristic analysis and compared with similar analysis of antinuclear antibody and double-stranded DNA (dsDNA). We demonstrated that native-MCP1, in contrast to bact-MCP1, reacts with SLE sera with significant predictive and discriminative power versus other autoimmune diseases (odds ratio [OR] ≤3.537 and ≥3.265; area under the receiver-operating characteristic curve [AUC] ≤0.643 and ≥0.636) or versus HBD (OR = 5.006; AUC = 0.671), showing a good diagnostic power with high specificity (82.1% versus HBD) and low sensitivity for SLE, similar to those of dsDNA. The reactivity of SLE sera with native-MCP1 was shown to be dependent on the presence of phosphorylated residues. Native-MCP1 was shown to have diagnostic value as a specific marker for SLE diagnosis and, therefore, is a suitable substrate for a new antibody test. The widely reported importance of phosphorylated epitopes as targets for autoantibodies in SLE could also be confirmed for native-MCP1.
authors.affiliation: Departamento de Ciências Biológicas, Laboratório de Bioquímica, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4050-047, Porto, Portugal. elsa.rocha@ff.up.pt
authors.forename: Elsa
authors.initials: E
authors.lastname: Bronze-da-Rocha
authors.forename: Ana
authors.initials: A
authors.lastname: Nóvoa
authors.forename: Natércia
authors.initials: N
authors.lastname: Teixeira
authors.forename: Carlos Silva
authors.initials: CS
authors.lastname: Vasconcelos
authors.forename: Conceição
authors.initials: C
authors.lastname: Cerveira
authors.forename: João
authors.initials: J
authors.lastname: Castro e Melo
authors.forename: Manuel Cirne
authors.initials: MC
authors.lastname: Carvalho
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood* / Q000276:immunology; D034961:Antigens, Nuclear / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000276:immunology; D001324:Autoantigens / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D017675:CREST Syndrome / Q000276:immunology; D045744:Cell Line, Tumor; D003882:Dermatomyositis / Q000276:immunology; D005260:Female; D006367:HeLa Cells; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008947:Mixed Connective Tissue Disease / Q000276:immunology; D011174:Portugal; D011928:Raynaud Disease / Q000276:immunology; D012595:Scleroderma, Systemic / Q000276:immunology; D012859:Sjogren's Syndrome / Q000276:immunology; D055815:Young Adult
chemical_list: D000974:Antibodies, Antinuclear; D034961:Antigens, Nuclear; D001324:Autoantigens; D015415:Biomarkers; C487774:metaphase chromosome protein 1, human