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Importance: Emicizumab (EMI) is efficacious and safe for hemophilia A (HA) prophylaxis. However, its high cost poses a challenge in China. Objective: To explore the possibility of using reduced‐dosage EMI in Chinese HA children. Methods: We conducted a retrospective study for HA children in our Comprehensive Care Center. Data were collected pre‐ and post‐EMI treatment to evaluate bleeding rates. Laboratory analyses included factor VIII (FVIII)‐like activity and EMI concentration measurements. Results: Thirty‐four HA children receiving EMI prophylaxis for a median (range) 24.5 (2.5–47.9) months by June 2023. Of these, 25 (73.5%) were under 3 years of age, 26 (76.5%) had severe hemophilia and 12 (35.3%) were minimally treated or previously untreated patients. Thirty‐one (91.2%) of the 34 patients received reduced‐dosage EMI for economic reasons. EMI concentration and FVIII‐like activity measured showed a strong correlation. Overall, while on EMI, their annual treated bleeding rate (ATBR) and annual bleeding rate (ABR) decreased significantly (2–0) while their zero‐bleeding rate (ZBR) increased significantly (11.5%–65.4%). After 6 months of EMI, there was no significant difference in ATBR and ABR among various maintenance dosages. However, ZBR was significantly lower in dosages under 4 mg/kg (P = 0.0156). Receiver operator characteristic curves suggested the following cutoff values for zero bleeding: EMI 4‐weekly maintenance dosage 3.8 mg/kg, EMI concentration 48.1 μg/mL, and FVIII‐like activity 15.4 IU/dL. Interpretation: We showed EMI effectively prevented bleeding even at reduced dosages. However, the bleeding risk may be higher with EMI 4‐weekly maintenance dosage <3.8 mg/kg, EMI concentration <48.1 μg/mL, and FVIII‐like activity <15.4 IU/dL for zero bleeding. It is important that dosage reduction be done rationally. Dosage tailoring is possible. [ABSTRACT FROM AUTHOR]

Importance: Joint disease affects more than 90% of severe hemophiliacs. Early diagnosis is critical in preventing hemophilic arthritis. Magnetic resonance imaging (MRI) enables visualization of early arthropathic changes and plays an important role in treatment., Objective: To evaluate the role of T2 mapping in detecting early cartilage lesions in the knee and ankle joints of children with hemophilic arthropathy., Methods: Target joints of 15 male patients with clinically confirmed moderate or severe hemophilia were evaluated with MRI. In addition to routine MRI protocols (T1WI, T2&#95;FFE, T2&#95;SPAIR, PDW&#95;TSE), T2 mapping was used to evaluate the articular cartilage of target joints., Results: The mean T2 value of the distal femoral cartilage was 46.72 ± 10.94 ms, which is higher than the reported age-matched normal value (40.27 ± 3.50 ms). The mean T2 value of the proximal tibial cartilage was 45.60 ± 8.82 ms, which is higher than the reported normal value (31.15 ± 1.86 ms). Four examined joints (two ankles, two knees) showed normal morphology with no abnormal signal on routine MR sequences. However, T2 mapping showed locally increased T2 values in the cartilage, along with uneven color scales., Interpretation: The quantitative assessment method of T2 mapping might be helpful to early diagnosis for articular cartilage lesions. It might be a potential tool for early assessment of cartilage changes and quantification of lesion's severity for hemophilia joint., Competing Interests: The authors declare that they have no competing interests., (© 2018 Chinese Medical Association. Pediatric Investigation published by John Wiley & Sons Australia, Ltd on behalf of Futang Research Center of Pediatric Development.)

Importance: Immune 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., Objectives: To evaluate platelet-specific antibodies and compare differences in their expression in childhood ITP to predict clinical progression., Methods: This 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., Results: Overall, 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). Interpretation., Interpretation: Patients 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., Competing Interests: The authors state that they have no conflicts of interest, (© 2018 Chinese Medical Association. Pediatric Investigation published by John Wiley & Sons Australia, Ltd on behalf of Futang Research Center of Pediatric Development.)

Competing Interests: The authors declare no potential conflicts of interest.