Platelet-specific antibodies and differences in their expression in childhood immune thrombocytopenic purpura predicts clinical progression.

Abstract

ABSTRACTImportanceImmune thrombocytopenic purpura (ITP) is the most common bleeding disorder in children. Despite the highly spontaneously remission, still almost 20% of cases progress into chronic or refractory ITP, which seriously affects children's quality of life. Currently there is no method to predict the initial stage of childhood ITP.ObjectivesTo evaluate platelet‐specific antibodies and compare differences in their expression in childhood ITP to predict clinical progression.MethodsThis is a single‐center prospective cohort study from April 2014 to October 2015. We enrolled children initially diagnosed as ITP. Anti‐GPIIb/IIIa and GPIb/IX antibodies were assayed by enzyme‐linked immunoadsorbent assay (ELISA) and patients were followed up for 1 year. We also analyzed the relationship between the expression of the platelet‐specific antibodies GPIIb/IIIa and GPIb/IX and their respective clinical prognoses.ResultsOverall, 134 cases were enrolled including 77 boys and 57 girls with a median age of 19 months (range: 1 to 159). Positive rates of anti‐platelet antibodies were 79.8%. After a 1‐year observation period, 84.3% were diagnosed as newly diagnosed ITP and 13.4% were diagnosed as chronic ITP. Patients with anti‐GPIIb/IIIa antibody had a higher risk for newly diagnosed ITP compared with patients who were anti‐GPIb/IX antibody positive only (93% vs 25%, P = 0.005; 87% vs 25%, P = 0.014, respectively). There were more anti‐GPIb/IX antibody positive only cases, diagnosed as chronic ITP, compared with anti‐GPIIb/IIIa antibody positive only cases and double GPIIb/IIIa and GPIb/IX antibody positive cases (75% vs 7%, P = 0.005; 75% vs 13%, P = 0.014, respectively). InterpretationInterpretationPatients with anti‐GPIIb/IIIa antibody (either single or double) were predicted to have a good prognosis, whereas anti‐GPIb/ IX antibody only predicted a poor prognosis. These results should be confirmed via a larger cohort multicenter study.