Transplant-associated thrombotic microangiopathy (TA-TMA) is an under-recognized yet potentially devastating complication of hematopoietic stem cell transplantation which had increased awareness in recent years. This report summarizes territory-wide experience of paediatric TA-TMA in the Hong Kong Children’s Hospital from 1 April 2019 to 31 March 2021. Total six patients were identified among 73 transplants performed. Median duration of onset was 2.5 months post-HSCT. Three patients died while all 3 survivors suffered from stage 2 to 5 chronic kidney disease despite administration of eculizumab. To conclude, recognition and diagnosis of TA-TMA is challenging. Clinical utility of complement blockage with eculizumab is limited.

Severe hypercholesterolemia mediated by graft-versus-host disease of liver in patients underwent allogeneic hematopoietic stem cell transplantation is a recognized yet overlooked phenomenon. Reports in literature is limited in both adult and pediatric population and none had been reported in Chinese children to date. As lipoprotein X hypercholesterolemia is due to regurgitation of cholesterol and bile salts into systemic circulation rather than overproduction by hepatocytes, usage of statins to downregulate cholesterol synthesis is not effective. Here we report 2 local cases to increase awareness of transplant physicians and endocrinologists of this association and avoid unnecessary and ineffective usage of statins.

Purpose We evaluated the existing risk assessment tools for CML in children. Patients and Methods A total of 55 patients from 1.4 to 18.0 years with newly diagnosed CML between 1996 and 2019 were included. Forty-nine patients presented in the chronic phase, thirty-six of whom were treated with upfront tyrosine kinase inhibitor (CP-TKI group); one presented in the accelerated phase and 4 in the blastic phase. Treatment, survival, responses, and tolerance were evaluated. Results The median follow-up time was 8.7 years (range, 2 months to 24.3 years). All patients in the CP-TKI group received imatinib as their first TKI treatment. Allogenic stem cell transplantation was performed in one patient after complete cytogenetic response was achieved with imatinib and in one patient with imatinib failure. Dasatinib and nilotinib were prescribed as second-line TKI in 5 patients and 4 patients respectively. The 10-year overall survival (OS), progression-free survival (PFS) and event-free survival (EFS) of TKI treated group was 97%, 91.4% and 72.3% respectively. The rates of major molecular response and deep molecular response of TKIs were 81.2% and 67.5% at 60 months. The EUTOS long-term survival (ELTS) risk grouping did not predict OS, PFS or EFS. The IMAFAIL risk groups are correlated with the risk of imatinib failure. Conclusion TKIs resulted in excellent long-term overall and progression-free survival in children and adolescents with newly diagnosed CML in the chronic phase. Further studies are required to modify the existing prognostic scoring system or develop new ones for children.

Background: Chronic benign neutropenia (CBN) and autoimmune neutropenia (AIN) are notoriously difficult to differentiate in children owing to their indistinguishable clinical course and varying availability and accuracy in the methods of anti-neutrophil antibody detection. This study aims to investigate whether the presence of anti-neutrophil antibody has implications on the disease course in Chinese children with AIN, as well as evaluating the various methods including LABScreen MULTI, granulocyte agglutination test (GAT) and granulocyte immunofluorescence test (GIFT) in anti-neutrophil antibody detection. Procedure: Chinese children under 18 years of age with neutropenia ≤ 1.5 x 109/L lasting 6 months or more in our single center were recruited into the study between 2016 to 2018. Patients with secondary causes of neutropenia were excluded. Blood for anti-neutrophil antibody and genotyping was taken once at the time of recruitment and subsequently when neutropenia recovered to ≥ 1.5 x 109/L. A combination of two in-house methods including GIFT, GAT and commercial kit LABScreenTM multipanel were used for the detection of antibodies. The age of onset, age of recovery, duration of neutropenia, gender, serial neutrophil counts, incidence of invasive infection, use of G-CSF were examined. Results: Using combined testing methods, anti-neutrophil antibody was detected in 30.8 % of patients and positivity was associated with more severe neutropenia, higher likelihood of infection and slower and later recovery compared to those without antibodies. Conclusions: The presence of anti-neutrophil antibody was useful in predicting the clinical course of patients with AIN. The use of combined testing methods increased the detection rate.

Jejunal feeding is increasingly utilized in the pediatric population to reduce gastroesophageal reflux or aspiration pneumonia. We describe a pediatric patient who developed persistent neutropenia and anemia secondary to copper deficiency after more than one year of exclusive jejunal feeding. Bone marrow aspiration and trephine biopsy showed vacuolated myeloid and erythroid precursors compatible with copper deficiency. Short term treatment with mineral mixture powder including copper reversed the hematological abnormalities. This report highlights the risk of micronutrient deficiency and the haematological manifestations as a result of acquired copper deficiency in pediatric patients receiving long term jejunal feeding.