Abstract Number: PB0791
Meeting: ISTH 2021 Congress
Background: Essential thrombocythemia (ET) is rare in pediatric patients, with uncertain criteria for diagnosis, prognosis and treatment strategies in real-world clinical practice.
Aims: The study aimed at trying to optimize the diagnostic, prognostic and therapeutic regimens based on existing evidence in pediatric ET.
Methods: A total of 86 pediatric patients (age≤16 years) with an initial diagnosis of ET according to the 2016 WHO diagnostic criterion were enrolled. The immunophenotype of bone marrow mononuclear cells and mutations in 137 genes associated with myeloid malignancies were analyzed in 55 children.
Results: The JAK2 V617F mutation was positive in 16 patients (18.6%). The CALR mutations were found in 3 of 62 patients (4.8%). None of them was MPL-mutated. Surprisingly, although bone marrow histology was consistent with a diagnosis of ET in all the 67 cases without driver mutations, a spontaneous normalization of the platelet count occurred in 7 cases (10.4%). We found that several factors might be ‘true ET’-specific, including palpable splenomegaly, presence of immunophenotypic abnormality (mainly showing reduced CD38 expression on myeloid blast cells and reduced CD36 expression on nucleated red blood cells), positive endogenous erythroid colonies, subnormal erythropoietin, and presence of molecular markers other than driver mutations. Severe splenomegaly was a risk factor of myelofibrosis transformation in children. The Efficacy and safety between pegylated interferon and regular interferon were compared for the first time in childhood patients. Better tolerance was seen in children using pegylated interferon. Furthermore, pegylated interferon was still effective and tolerant in 8 children that were resistant or intolerant for regular interferon.
Conclusions: Based on the 2016 WHO diagnostic criterion for ET, several ‘true ET’-specific features might be considered for the diagnostic screening of childhood ET. Prognostic factors for children are different from that for adult patients. Pegylated interferon has an extensive prosperity in childhood ET.
To cite this abstract in AMA style:Fu R, Zhang D, Li H, Xue F, Liu X, Chen Y, Liu W, Yang R, LZ. Essential Thrombocythemia in Children: A Retrospective, Real-world Study Conducted in China [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/essential-thrombocythemia-in-children-a-retrospective-real-world-study-conducted-in-china/. Accessed June 6, 2023.
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