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.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disorder due to mutations in the TYMP gene. Clinical findings are characterized by neurologic manifestations and severe gastrointestinal dysfunction. The syndrome is usually fatal, the most effective treatment appears to be hematopoietic stem cell transplantation (HSCT). Aim:In this retrospective study, we evaluated HSCT that was performed using a reduced toxicicity myeloablative conditioning regimen in patients with MNGIE at our center. Results: A total of 6 allogeneic transplant procedures were performed in 4 patients. Three patients’ donors had fully matched donors, and one patients’ donor was haploidentical. Treosulfan-based myeloablative conditioning regimen was applied in 5 of 6 transplants. Bone marrow was used as a stem cell source. One patient is being followed up in the 4th year of posttransplant with full chimeric and without Graft versus host disease (GVHD). One patient died of acute stage IV GIS GVHD. Two patients underwent second transplantation due to engraftment failure, one of which was the patient who had a haploidentical transplant. Conclusions: Treosulfan-based regimen is well tolerated. Engraftment failure with this conditioning regimen can be a significant problem. We share our haploidentical transplant experience, which will be the first reported case in the literature.

Background: With the widespread use of hematopoietic stem cell transplantation (HSCT), long-term complications have come to the fore. The aim of this study is to determine the prevalence and risk factors of chronic kidney disease (CKD) developing in the long term in patients who underwent allogeneic HSCT in childhood and also to investigate the superiority of eGFR formulas. Methods: The present study evaluated CKD in patients undergoing allogeneic HSCT. We analyzed the 94 children who received allogeneic HSCT at the Ege University in İzmir between 2019 August and 2019 November. The patients were evaluated at least 2 years after transplantation. CKD was defined as a glomerular filtration rate (GFR)<90 mL/min/1.73 m2, using eGFR equations which are based on serum creatinine (SCr), cystatin C (CysC), and SCr plus CysC. Results: In our study, 9 (9.4%) according to Bedside Schwartz, 59 (76.6%) according to CKiD-eGFR-CysC and 20 (26%) patients according to CKiD-eGFR-SCr-CysC equation were evaluated as CKD. In cases evaluated as CKD according to CysC, early development of acute kidney injury (AKI), posttransplant cytomegalovirus (CMV) reactivation and being >10 years old during transplantation were found to be associated with the development of CKD. Conclusion: We may be delayed in detecting CKD by calculating SCr-based formulas in HSCT cases, which is a patient group where early diagnosis and treatment of CKD is very important.