HLA Haploidentical Stem Cell Transplant with Pretransplant Immunosuppression for Patients with Sickle Cell Disease.

Allogeneic stem cell transplantation (HCT) is curative in patients with severe sickle cell disease (SCD), but a significant number of patients lack an HLA-identical sibling or matched unrelated donor. Mismatched related (haploidentical) HCT with post-transplant cyclophosphamide (PTCY) allows expansion of the donor pool but is complicated by high rates of graft failure. In this report we describe a favorable haploidentical HCT approach in a limited cohort of SCD patients with significant comorbidities. To reduce the risk of graft failure we administered the conditioning regimen of rabbit antithymocyte globulin, busulfan, and fludarabine preceded with 2 courses of pretransplant immunosuppressive therapy (PTIS) with fludarabine and dexamethasone. Graft-versus-host disease (GVHD) prophylaxis consisted of PTCY on days +3 and +4 followed by tacrolimus and mycophenolate mofetil starting on day +5. Four patients (ages 13, 19, 19, and 23 years) received T cell-replete haploidentical stem cell infusion. All patients engrafted with 99.9% to 100% donor chimerism, and all patients continued with stable engraftment at the last follow-up (5 to 11 months post-transplant). Time to neutrophil engraftment was 14 to 26 days. Two patients had high levels of donor-specific anti-HLA antibodies, which required the implementation of an antibody management protocol. This facilitated neutrophil engraftment on day +16 and day +26, respectively. One patient developed grade I acute GVHD, which resolved. Three patients developed mild, limited skin GVHD that responded to conventional immunosuppressive therapy. Human herpesvirus-6 viremia was detected in 3 patients but resolved without treatment. One patient developed asymptomatic cytomegalovirus viremia that responded appropriately to standard therapy with ganciclovir. The prompt, stable engraftment and low toxicity in the post-transplant period makes PTIS with haploidentical transplant a promising option for patients with SCD.

Venous Thromboembolism Risk Assessment and Prophylaxis Use in Pediatric, Adolescent, and Young Adult Hematology Oncology Patients.

No widely accepted method exists to evaluate pediatric hematology oncology patients for the risk of venous thromboembolism (VTE) and the need for prophylaxis. The use of a VTE risk-assessment tool and standardized guidelines for prophylaxis could increase the use of appropriate prophylaxis and reduce the number of VTEs in patients, thereby decreasing morbidity, mortality, hospitalization, and cost. The purpose of this project was to implement and assess the compliance of a pediatric-specific VTE risk-assessment tool in hospitalized pediatric, adolescent, and young adult hematology oncology patients. From the 114 pediatric, adolescent, and young adult patients requiring assessment, 91 (80%) VTE assessments were completed and 87 (96%) were completed accurately. Eighty percent of the at-risk patients were ordered VTE prophylaxis. The use of a VTE risk-assessment tool in pediatric hematology oncology patients is a feasible way to assess patients for their risk of developing a VTE.