Prognostic Re-evaluation of Anti-Nuclear Antibodies in Childhood Immune Thrombocytopenia.

Background: In the autoimmune bleeding disorder childhood immune thrombocytopenia (ITP), antinuclear antibodies (ANA) have been suggested as potential biomarkers for predicting chronic ITP. Unfortunately, published evidence remains conflicting and testing is not currently recommended in clinical routine. Aim: This study aimed to validate the prognostic association of ANA with chronic ITP in newly diagnosed childhood ITP. Methods: Data from 176 children with newly diagnosed ITP and a platelet count ≤ 20 x 10^9/L enrolled in the TIKI randomized controlled trial were available. ANA testing was performed on sera obtained within 72 hours of diagnosis, before immunomodulatory treatment. Children were followed for 12 months to assess chronic ITP development, IVIg treatment response, and spontaneous recovery. Results: ANA were detected in 36/176 (20%) children. Chronic ITP developed in 21/176 children; 4/36 (19%) of ANA-positive versus 17/136 (12%) of ANA-negative patients (OR 0.90; 95% CI, 0.25 - 2.65). No differences were observed in platelet counts, spontaneous recovery or IVIg responses when comparing children with and without ANA. ANA provided no additional prognostic value beyond the Childhood ITP Recovery Score, a clinical prediction rule for recovery from ITP. ANA were not associated with anti-platelet antibodies by PIFT or MAIPA. Conclusion: ANA testing at the time of diagnosis was not helpful to predict chronic ITP, IVIg treatment responses, or spontaneous recovery among children with newly diagnosed ITP and a platelet count ≤ 20 x 10^9/L. Future studies may evaluate whether ANA testing may be of value when performed at a later point in time.