title: Autoantibodies and their Judicious Use in Pediatric Rheumatology Practice.
abstract: Autoantibody testing forms an important part of diagnostic workup of patients in Pediatric rheumatology practice. However it is important to understand that the mere presence of autoantibodies does not necessarily mean the presence of an underlying autoimmune disease. Autoantibodies may be present decades before the development of clinical manifestations of an autoimmune disease and may be viewed as harbingers of Autoimmune disease. On the other hand, low-affinity autoantibodies may be present in normal healthy individuals; these natural autoantibodies serve an important function in immune regulation and tolerance. Autoantibody testing in pediatric practice mainly includes testing for anti-nuclear antibodies, anti-dsDNA antibodies, anti-neutrophil cytoplasmic autoantibodies and antiphospholipid antibodies. Rheumatoid factor and anti-CCP do not have much significance in the diagnostic schema in pediatric rheumatology, except perhaps for classification of juvenile idiopathic arthritis (JIA) and prognostication in late-onset polyarticular JIA. The positive predictive value (PPV) of any laboratory test depends on the prevalence of the disease in the population being tested. Hence, test ordering practices greatly impact the performance characteristics and positive predictive value of any laboratory test. A restricted test ordering only in patients with clinical signs and symptoms suggestive of autoimmune disease would thus greatly increase the PPV of tests such as antinuclear antibody used for diagnosing autoimmunity.
authors.affiliation: Department of Immunopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Biman
authors.initials: B
authors.lastname: Saikia
authors.affiliation: Pediatric Allergy and Immunology Unit, Advanced Pediatric Centre, Postgraduate Institute of Medical Education and Research, Sector 12, Chandigarh, 160012, India. rawatamit@yahoo.com.
authors.forename: Amit
authors.initials: A
authors.lastname: Rawat
authors.affiliation: Pediatric Allergy and Immunology Unit, Advanced Pediatric Centre, Postgraduate Institute of Medical Education and Research, Sector 12, Chandigarh, 160012, India.
authors.forename: Pandiarajan
authors.initials: P
authors.lastname: Vignesh
mesh_terms: D001323:Autoantibodies / Q000032:analysis / Q000097:blood / Q000145:classification; D002648:Child; D006801:Humans; D007159:Immunologic Tests / Q000379:methods; D011237:Predictive Value of Tests; D012216:Rheumatic Diseases / Q000175:diagnosis / Q000276:immunology
chemical_list: D001323:Autoantibodies
keywords: Anti-citrullinated peptide antibody; Anti-neutrophil cytoplasmic antibody; Anti-nuclear antibody; Antiphospholipid antibody; Autoantibody; Rheumatoid factor