Sistema FMUSP-HC: Faculdade de Medicina da Universidade de São Paulo (FMUSP) e Hospital das Clínicas da FMUSPKAMIOKA, Priscila E.LIPHAUS, Bernadete L.BEATRICE, Julia M.MATSUMOTO, Lucy C.REIS, Joyce M. A.LIMA, LailaCARNEIRO-SAMPAIO, Magda M. S.CARNEIRO, Jorge D. A.2020-12-162020-12-162020JOURNAL OF PEDIATRIC HEMATOLOGY ONCOLOGY, v.42, n.7, p.E606-E609, 20201077-4114https://observatorio.fm.usp.br/handle/OPI/38417Autoantibodies are biomarkers for autoimmune disease diagnosis, monitoring, and prediction. Therefore, this study established the frequency of latent and overt polyautoimmunity in children and adolescents with >6 months of diagnosis of immune thrombocytopenia (ITP). Forty-seven patients with chronic or persistent disease had non-organ-specific and organ-specific autoantibodies assessed. Frequency of latent polyautoimmunity was 36.2%, and, of overt polyautoimmunity, it was 4.3%. Of ITP patients with latent polyautoimmunity, 52.9% were positive for antinuclear antibody (ANA), 47.1% for autoantibodies other than ANA, and 64.7% for multiple autoantibodies. In addition, patients with latent polyautoimmunity and those positive for ANA were significantly older at disease onset. Both ITP patients positive and negative for autoantibodies reported family members with autoimmune diseases. The autoantibodies observed were as follows: ANA, anti-dsDNA, anti-SSA/Ro, IgM aCL, anti-GAD, anti-IA2, anti-IAA, anti-TG, anti-TPO, anti-LKM1, and SMA. Of ITP patients with overt polyautoimmunity, 1 was diagnosed with type 1 diabetes mellitus and the other with thyroiditis. In conclusion, children and adolescents with ITP present high frequency of latent and overt polyautoimmunity even for autoantibodies other than ANA. Therefore, ANA and other non-organ-specific and organ-specific autoantibodies should be considered for assessment during ITP patients' follow-up.engrestrictedAccessautoantibodiesbiomarkersimmune thrombocytopeniapolyautoimmunityantinuclear antibody-testclinical-significanceantithyroid antibodiesautoimmune hepatitisautoantibodiesprevalencedefinitionsdiseasespurpuraarticleCopyright LIPPINCOTT WILLIAMS & WILKINS10.1097/MPH.0000000000001836OncologyHematologyPediatrics1536-3678