Introduction: Bone marrow (BM) has been used as the source of stem cells for allogeneic hematopoietic stem cell transplant. However, peripheral blood stem cells (PBSC) for allogeneic HSCT have gained more popularity after the recent use of granulocyte colony-stimulating factor (G-CSF) for mobilization. Adult studies of the BM product mobilized using G-CSF (G-BM) have shown faster white blood cell engraftment, similar to that produced by PBSC, however, with less acute and chronic graft versus host disease disease. Methods: In order to increase the CD34 cell content of the bone marrow product, three different G-CSFs were used: biosimilar filgrastim (Leucostim®) (n=29), original filgrastim (Neupogen®) (n=30), and lenograstim (Granocyte®) (n=30). These G-CSFs were compared with one another and with the control group (n=30). The data obtained with the products collected from the BM of healthy donors in the control group and those who received G-CSF were analyzed. All donors were administered G-CSF 10 µg/kg daily at least 24 hours before BM harvesting. Results: In terms of the amount of CD34/UL per microliter BM harvesting, the group receiving Lenograstim (Granocyte®) was found to have a statistically significant higher CD34/UL value compared to the other groups. There was no statistically significant difference between the median CD34/UL values across the control, filgrastim and biosimilar-filgrastim groups. Biosimilar filgrastim (Leucostim®), original filgrastim (Neupogen®) and lenograstim (Granocyte®) can be safely used for BM CD34 cell mobilization in donors of patients undergoing allo-HSCT. Conclusion: Considering the amount of CD34/UL collected in the product, Lenograstim (Granocyte®) should be more preferable.

Background: Data on the outcome and risk factors of pediatric patients with SARS-CoV-2 infection (COVID-19) following hematopoietic stem cell transplantation (HSCT) are limited. Objectives: We aimed to describe risk factors for a severe course and mortality. Method: In this nationwide study, data were collected retrospectively from 28 transplant centers. Results: One hundred ninety-six children [(63.8% male; median age 8.75 (IQR, 4.86-14.30)] who received allogeneic (n: 184, 93.9%) or autologous (n: 12, 6.1%) HSCT were included. The median time from HSCT to SARS-CoV-2 infection was 207.5 days (IQR, 110.2-207.5). The most common clinical manifestation was fever (58.2%), followed by cough (33.7%); 43 cases (21.9%) were asymptomatic. Lower respiratory tract disease (LRTD) and multisystem inflammatory syndrome in children (MIS-C) developed in 58 (29.6%) and 8 (4.1%) patients, respectively. Twenty-six patients (13.3%) required ICU admission. Nine patients died at a median of 17 days (min-max 1-33) after COVID-19 diagnosis, 6 of whom died due to the disease, with a COVID-19 lethality rate of 3.1%. The 6-week overall survival was 95.4% (95% CI 92.5-98.3). Multivariate analysis found that HSCT with a mismatched donor (OR, 8.98, p: 0.039) and LRTD (OR, 61.55, p: 0.001) were independent risk factors for ICU admission; MIS-C (OR, 9.55, p: 0.044) and lymphopenia (OR, 4.01, p: 0.030) at diagnosis were risk factors for mortality. Conclusion: Overall mortality was lower in children than in adult counterparts, and HSCT with a mismatched donor, lymphopenia, LRTD, MIS-C and ICU admission were important risk factors for adverse outcomes.

Ewing sarcoma is children’s second most common malignant bone tumor after osteosarcoma. Relapsed and/or treatment-refractory cases have a poor prognosis. Cabozantinib is a tyrosine kinase inhibitor (TKI) that targets vascular endothelial growth factor (VEGF) and MET. Here, we present data on two children with metastatic Ewing sarcoma who received cabozantinib therapy. In both cases, the disease regressed significantly, symptoms improved, and side effects were manageable. Further research is needed to determine whether cabozantinib can maintain sustained disease control in children with Ewing sarcoma.