Anti-glycoprotein autoantibodies are related to bleeding severity in children with newly diagnosed ITP and very low platelet counts.

BACKGROUND AND OBJECTIVE: Immune thrombocytopenia (ITP) is an autoimmune-mediated hemorrhagic disease. Anti-glycoprotein autoantibodies play a key role in the pathophysiology of ITP, but the relationship between platelet-specific antibodies and bleeding severity is unclear. This study aimed to analyze the relationship between anti-glycoprotein autoantibodies and bleeding severity in children with newly diagnosed ITP and platelet count less than 10 × 109 /L. METHOD: This was a single-center prospective observational study that analyzed children with newly diagnosed ITP and platelet count less than 10 × 109 /L between June 2018 and September 2021 at our hospital. The children were classified into the mild and severe groups based on the bleeding scores. The type and titer of anti-glycoprotein autoantibodies were detected using an enzyme-linked immunosorbent assay (ELISA) kit (PAKAUTO). We analyzed the relationship between bleeding severity and anti-glycoprotein autoantibodies. RESULTS: A total of 86 cases were enrolled, including 42 in the mild group and 44 in the severe group. Patients with anti-GPIIb/IIIa or anti-GPIb/IX antibodies suffered more severe bleeding than patients without them (χ2 = 7.303, p = .007; χ2 = 3.875, p = .049), but there was no significant difference between patients with or without anti-GPIa/IIa antibodies (χ2 = 0.745, p = .388). When antibodies were analyzed together, patients with three antibodies suffered more severe bleeding than those without three antibodies (χ2 = 5.053, p = .025). Patients with higher antibody titer in the eluent, but not in the plasma, suffered more severe bleeding in all three antibodies (Z = -2.389, p = .017; Z = -2.108, p = .035; Z = -2.557, p = .011). CONCLUSION: Anti-glycoprotein autoantibodies led to more severe bleeding in children under 18 years of age without drug treatment with newly diagnosed ITP and platelet count less than 10 × 109 /L.