title: Autoantibodies in prediction of the development of rheumatoid arthritis among healthy relatives of patients with the disease.
abstract: OBJECTIVE
  Although blood bank-based studies have shown that rheumatoid arthritis (RA)-related autoantibodies are present before the onset of RA, information on their positive predictive value (PPV) for development of RA in healthy individuals is scarce. This study was undertaken to assess the 5-year PPV of serum IgM rheumatoid factor (IgM-RF) and anti-cyclic citrullinated peptide (anti-CCP) for the development of RA among healthy relatives of patients with RA.
  
  
  METHODS
  Healthy relatives of RA patients were invited to participate in a cohort study. At baseline, information on participants' medical history was obtained, and serum levels of IgM-RF and anti-CCP antibodies were determined (by nephelometry and second-generation anti-CCP enzyme-linked immunosorbent assay, respectively). The subjects were followed up every 4 months via a structured interview (Community Oriented Program for Control of Rheumatic Diseases [COPCORD] questionnaire). When the COPCORD questionnaire indicated possible arthritis, subjects underwent an in-office rheumatology assessment including joint count. The study end point was defined as fulfillment of the American College of Rheumatology criteria for RA.
  
  
  RESULTS
  Eight hundred nineteen initially healthy relatives of 252 patients with RA were included (69% female, 41% offspring, mean ± SD age 35 ± 12 years). Eleven (1.3%) were positive for both anti-CCP-2 and RF, 12 (1.5%) only for anti-CCP-2, and 16 (2%) only for RF. RA developed in 17 (2.1%) of the relatives during the 5-year followup (3,313 person-years for the seronegative group and 60.8 person-years for the anti-CCP-2-positive group). The PPV was 64% when both anti-CCP-2 and RF were positive and 58% when only anti-CCP-2 was positive. Offspring of patients with RA had an independent 3-fold increased risk of developing RA.
  
  
  CONCLUSIONS
  Results of the present study indicate that the magnitude of risk for developing RA in healthy relatives of patients with RA can be estimated using simple routine laboratory tests.
authors.affiliation: Centro de Investigacion Biomedica de Occidente, Instituto Mexicano del Seguro Social and Unidad de Investigacion en Enfermedades Cronico-Degenerativas, Guadalajara, Mexico.
authors.forename: Cesar
authors.initials: C
authors.lastname: Ramos-Remus
authors.affiliation: Unidad de Investigacion en Enfermedades Cronico-Degenerativas, Guadalajara, Mexico.
authors.forename: Jose Dionisio
authors.initials: JD
authors.lastname: Castillo-Ortiz
authors.affiliation: Unidad de Investigacion en Enfermedades Cronico-Degenerativas, Guadalajara, Mexico.
authors.forename: Luis
authors.initials: L
authors.lastname: Aguilar-Lozano
authors.affiliation: Unidad de Investigacion en Enfermedades Cronico-Degenerativas, Guadalajara, Mexico.
authors.forename: Jorge
authors.initials: J
authors.lastname: Padilla-Ibarra
authors.affiliation: Unidad de Investigacion en Enfermedades Cronico-Degenerativas, Guadalajara, Mexico.
authors.forename: Carlos
authors.initials: C
authors.lastname: Sandoval-Castro
authors.affiliation: Unidad de Investigacion en Enfermedades Cronico-Degenerativas, Guadalajara, Mexico.
authors.forename: Cesar Omar
authors.initials: CO
authors.lastname: Vargas-Serafin
authors.affiliation: Unidad de Investigacion en Enfermedades Cronico-Degenerativas, Guadalajara, Mexico.
authors.forename: Hector
authors.initials: H
authors.lastname: de la Mora-Molina
authors.affiliation: Unidad de Investigacion en Enfermedades Cronico-Degenerativas, Guadalajara, Mexico.
authors.forename: Ariadna
authors.initials: A
authors.lastname: Ramos-Gomez
authors.affiliation: Unidad de Investigacion en Enfermedades Cronico-Degenerativas, Guadalajara, Mexico.
authors.forename: Adriana
authors.initials: A
authors.lastname: Sanchez-Ortiz
authors.affiliation: Hospital Civil Dr. Juan I. Menchaca, Guadalajara, Mexico.
authors.forename: Hilario
authors.initials: H
authors.lastname: Avila-Armengol
authors.affiliation: Hospital General Regional 46, Instituto Mexicano del Seguro Social, Guadalajara, Mexico.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Aceves-Avila
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology*; D012217:Rheumatoid Factor / Q000276:immunology*; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D007075:Immunoglobulin M; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D012217:Rheumatoid Factor