Vitamin K deficiency in children pre-bone marrow transplantation

[Advances in nutritional support for children undergoing hematopoietic stem cell transplantation]

Hematopoietic stem cell transplantation (HSCT) is a therapeutic option for various potentially life-threatening malignant and non-malignant diseases in children, such as malignancies, immunodeficiency syndromes, severe aplastic anemia, and inherited metabolic disorders. During transplantation, many factors can affect the nutritional status of the children, including radiotherapy, chemotherapy, gastrointestinal disorders, graft-versus-host disease, and medications. Malnutrition has been associated with decreased overall survival and increased complications in children undergoing HSCT, making nutritional support a crucial component of their management. However, currently, there is a lack of guidelines or consensus on nutritional support for children undergoing HSCT in China. Therefore, this review summarizes the progress in nutritional support for children undergoing HSCT, aiming to provide clinical guidance.

Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: children and adolescents

The Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: Children and Adolescents was developed by dietitians, physicians, and pediatric hematologists from 10 Brazilian reference centers in hematopoietic stem cell transplantation. The aim was to emphasize the importance of nutritional status and body composition during treatment, as well as the main characteristics related to patient´s nutritional assessment. This consensus is intended to improve and standardize nutrition therapy during hematopoietic stem cell transplantation. The consensus was approved by the Brazilian Society of Bone Marrow Transplantation.

Platelet gene therapy by lentiviral gene delivery to hematopoietic stem cells restores hemostasis and induces humoral immune tolerance in FIX(null) mice

Here, we developed a clinically translatable platelet gene therapy approach for hemophilia B. Platelet-targeted FIX (2bF9) expression was introduced by transplantation of hematopoietic stem cells (HSCs) transduced with 2bF9 lentivirus (LV). Sustained therapeutic levels of platelet-FIX expression were obtained in FIX(null) mice that received 2bF9 LV-transduced HSCs. Approximately 6-39% of the platelets expressed FIX in the transduced recipients, which was sufficient to rescue the bleeding diathesis in FIX(null) mice in tail clipping models. Sequential bone marrow transplantation demonstrated that platelet-FIX expression in the secondary recipients was sustained, leading to phenotypic correction. Notably, none of the transduced recipients developed anti-FIX antibodies after platelet gene therapy. Only one of the nine recipients developed a low titer of inhibitory antibodies (1.6 BU/ml) after challenge with rhFIX. These data suggest that platelet gene therapy can not only restore hemostasis but also induce immune tolerance in hemophilia B mice, indicating that this approach may be a promising strategy for gene therapy of hemophilia B in humans.

Incidence of symptomatic venous thromboembolism following hematopoietic stem cell transplantation

BACKGROUND

The incidence of symptomatic venous thromboembolism (VTE) following hematopoietic stem cell transplantation (HSCT) is not well described, particularly with increased use of ambulatory care in the transplant setting.

METHODS

A retrospective analysis involving 589 patients (382 autologous HSCT, 207 allogeneic HSCT) undergoing transplantation between 2000 and 2005 in a single Canadian institution was undertaken to identify the incidence of proximal deep vein thrombosis (DVT) or pulmonary embolism (PE) in HSCT patients.

RESULTS

The total 1-year incidence of symptomatic VTE was 3.7% [95% confidence interval (CI) 2.5-5.6]. Among the HSCT patients, 7/589 (1.2%, 95% CI 0.6-2.4) developed symptomatic non-catheter-related VTE following HSCT (four PE and three DVT). All VTE events occurred after hematopoietic engraftment. Patients undergoing autologous HSCT did not receive thromboprophylaxis, whereas most patients undergoing allogeneic HSCT (79.7%) received enoxaparin 20 mg daily for the prevention of veno-occlusive disease of the liver, starting 6 +/- 3 days before transplantation for a mean of 22 +/- 14 days.

CONCLUSION

HSCT patients have a high incidence of VTE. Thromboprophylaxis should potentially be considered in these patients. However, future studies assessing the risk and benefits of thromboprophylaxis are needed in this specific population.

A prospective longitudinal multicenter study of coagulation in pediatric patients undergoing allogeneic stem cell transplantation

BACKGROUND

Thrombotic complications occur in adult patients undergoing stem cell transplantation (SCT), especially following high dose chemo-radiotherapy. There is little published information in children on the impact of SCT on coagulation, as well as potential correlations between altered coagulation and SCT-associated thrombosis and organ failure.

PROCEDURE

Forty three pediatric subjects who underwent allogeneic SCT were prospectively evaluated for congenital thrombophilia, anticoagulant levels, coagulation activation, and fibrinolysis at pre-established set points encompassing the period from the 2 to 4 weeks prior to conditioning to 28 days post-transplantation.

RESULTS

A significant decrease of protein C and antithrombin levels was found in 39% and 31% of subjects respectively, between SCT days +6 and +7. A peak in plasminogen activator inhibitor-1 levels in 31% of subjects was noted between days +9 and +10. No subject experienced a thrombotic event or other SCT-related organ failure. Antithrombin deficiency correlated with underlying malignancy, donor HLA-mismatch, and TBI, whereas decreased PC activity demonstrated a trend of association with lack of T-cell depletion and TBI. Prophylactic heparin did not influence the pattern of acquired hemostatic abnormalities observed in this cohort.

CONCLUSIONS

Children undergoing allogeneic SCT develop a state of acquired thrombophilia in the early post-transplantation period. Although no SCT-related thromboembolic events were observed, our results provide new information about the hemostatic changes in children undergoing allogeneic SCT and their potential clinical triggers. The significance of these findings requires further prospective evaluation in a larger cohort of patients.