Haploidentical Stem Cell Transplantation with CD3+/CD19+ ex-vivo depletion is a therapeutic option in children without a matched donor, or after graft failure: Experience at the National Institute of Pediatrics

Hematopoietic stem cell transplantation is a widely used therapy for different diseases in the pediatric population. Haploidentical transplantation with negative immunoselection using electromagnetic fields is an alternative for those patients without an HLA-matched donor. Twenty pediatric patients under 18 years old received a haploidentical CD3+/CD19+-depleted transplant due to the absence of an HLA-matched donor. The mean age at which HSCT was performed was 6.6 years (range 1-18 years), and clinical indications were: acute lymphoblastic leukemia (9 patients), primary immunodeficiency (8 patients), acute myeloid leukemia (2 patients), and severe aplastic anemia (1 patient). The medium dose of cells infused was 10.9 (min. 2, max. 32) x 106/kg CD34+ cells, 3.2-4.1 x 105/kg CD3+ cells and 2.4-3.7 x 105/kg CD19+ cells. Results: Eleven of the twenty patients had donor engraftment (55%) and had complete chimera of their donors. From this group, nine (45%) developed primary graft failure, and four (36%) developed graft-versus-host disease. In the group of leukemia patients, overall survival was 75% while event-free survival was 40%. Haploidentical transplantation with negative immunoselection is a useful and feasible strategy for children without an ideal donor. In our cohort, patients with acute leukemia had better outcomes than patients with non-malignant diseases.