title: Low positive rate of serum autoantibodies in colorectal cancer patients without systemic rheumatic diseases.
abstract: Antinuclear antibody (ANA) testing is useful for screening, diagnosis and follow-up of patients with systemic rheumatic diseases. Indirect immunofluorescence (IIF) on HEp-2 cells is the gold standard for ANA testing. However, ANA have also been detected in patients with different cancer types but without any autoimmune disease. To overcome these shortcomings, different automated solid-phase assays have been developed.
  
  
  
  To determine the positive rate of a new ANA detection method (EliA CTD Screen, Phadia, Germany), in CRC patients without systemic rheumatic diseases. Additionally, we compare this method with IIF.
  
  
  
  Serum samples were obtained before a colonoscopy procedure in a patient cohort (n = 186) with a high clinical suspicion of CRC. Samples for ANA detection in CRC patients were processed in parallel by IIF on HEp-2 and the solid-phase fluoroenzymeimmunoassay EliA CTD Screen (Phadia, Germany) on the Phadia 250 instrument (Phadia GmbH, Freiburg, Germany). Positive samples by IIF and/or CTD were tested with EliA single ANA assays (Phadia, Germany) on the Phadia 250 instrument (Phadia GmbH, Freiburg, Germany).
  
  
  
  Forty-five patients diagnosed with CRC were included. Four cases were positive by CTD and 23 by IIF. Of the four positive patients by CTD, two were positive and one indeterminate for anti-dsDNA antibodies. Of the 23 positive by IIF, one patient was positive and another indeterminate for anti-dsDNA antibodies, and a third patient was positive for anti-U1RNP antibodies.
  
  
  
  The CTD assay shows a low false positive rate for detecting autoantibodies in a clinical context of CRC.
authors.affiliation: a Department of Biotechnology , Alto Guadalquivir Hospital , Andújar (Jaén) , Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Fernández-Suárez
authors.affiliation: b Laboratory of Clinical Analysis , General Universitario De Ciudad Real Hospital , Ciudad Real , Spain.
authors.forename: Aurora
authors.initials: A
authors.lastname: Muñoz-Colmenero
authors.affiliation: c UGC Laboratory, Department of Immunology, Complejo Hospitalario , Jaén , Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Ocaña-Pérez
authors.affiliation: a Department of Biotechnology , Alto Guadalquivir Hospital , Andújar (Jaén) , Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Fatela-Cantillo
authors.affiliation: d Department of Gastroenterology , Alto Guadalquivir Hospital , Andújar (Jaén) , Spain , and.
authors.forename: José L
authors.initials: JL
authors.lastname: Domínguez-Jiménez
authors.affiliation: e Department of Pathology , Alto Guadalquivir Hospital , Andújar (Jaén) , Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Díaz-Iglesias
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000974:Antibodies, Antinuclear / Q000097:blood / Q000276:immunology; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology*; D015179:Colorectal Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011446:Prospective Studies
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies
keywords: Antinuclear antibodies; EliA CTD screen; autoimmune diseases; colorectal cancer; indirect immunofluorescence