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.

Background: Tissue Doppler (TD) measurements give a better information in evaluating the myocardial functions than conventional echocardiography in beta-thalassemia major (β-TM). The aim of this study was to determine cardiac status of thalassemia patients by using both T2*MRI and TD. Methods: The study group included thalassemia patients (n=33) with normal systolic functions defined by conventional echocardiography. The control group (n=37) consisted of age and sex matched healthy individuals. TD measurements from three different regions of myocardium were obtained in both groups. Ferritin was examined in both groups, T2*MRI was performed only patients with thalassemia. Results: Systolic and diastolic functions were found normal by conventional echocardiography in thalassemia patients. However, cardiac functions were significantly impaired when evaluated by TD (p<0.05). T2*MRI and TD measurements didn’t differ according to serum ferritin levels (p>0.05). Twenty-one patients (63.6%) had myocardial iron overload. Both isovolumetric acceleration time of left ventricle and myocardial performance index (MPI-septal) were found significantly impaired in these patients (p<0.05). There was negative correlation between MPI-septal and T2*MRI measurements in thalassemia patients (r:-0.343, p=0.050). TD measurements obtained from septum were found similar with the control (p>0.05) but, the same measurements from left and right ventricular walls were significantly impaired in iron unloaded group (p< 0.05). Coclusion: Iron unloaded patients according to T2*MRI had left and right ventricular dysfunction determined by TD. Therefore, we suggest that combining T2*MRI with TD measurements, for evaluating cardiac status in β-TM, in whose with normal T2*MRI scores, would be better management of cardiac complications.