Haploidentical Stem Cell Transplantation As a Therapeutic Option in Children with Previous Cord Blood Transplantation and Graft Failure. Successful Results in a Mexican Hospital

Currently, in our environment, 50% of patients requiring transplantation cannot undergo this procedure due to lack of a donor.

Twenty patients with different pathologies Eleven patients had graft acceptance (55%) with complete chimerism. Nine (45%) patients had primary graft failure. Of the patients subjected to HT as rescue in case of cord graft failure, it was noted that 100% of the patients are alive after 40 months of follow-up with a statistically significant difference (p = 0.02) compared with those subjected to HT as the primary choice.

This case review describes HT as a therapeutic tool in children without available donor. Our objective was to describe the clinical features, complications and deaths in a series of children undergoing HT in the Instituto Nacional de Pediatria (INP) since 2009.

We included all patients undergoing HT  between July 2009 and November 2012 .

Conditioning was done with fludarabine (30 mg/m²) for 2 days, anti-thymocyte globulin (1.5 mg/kg/day) for 3 days, nodal radiotherapy (7 Gy) and melphalan (70 mg/m²/day) for 2 days. For graft vs. host disease (GVHD) prophylaxis, cyclosporine (6 mg/kg/day) was used from day -1.

The method of CD34+ selection was contemplated for patients with immunodeficiency and CD3+ depletion for patients with oncology/hematology diseases.

For bivariate analysis of qualitative variables, c²and Student t test were performed. OS and DFS curves were performed with the Kaplan-Meier method using SPSS v.20.0. Differences between the rates of OS or DFS based on cell dose, age, gender, and paternal or maternal donor were made using the log-rank test; p<0.05 was considered significant.

The median of cells infused was as follows: CD34+ 10.9 x 10⁶/kg (range: 2 to 32 x 10⁶/kg), CD3+ 14.2 x 10⁵/kg and CD19+ 3.4 x 10⁵/kg.

11 patients achieved graft (55%) with complete chimerism. Nine patients (45%) had primary graft failure. Of the 11 patients with complete chimerism, two patients had graft loss due to relapse of ALL (at 4 and 12 months post-HT). In a third case there was loss of the graft due to cytomegalovirus (CMV) at 21 months post-HT.Of the patients subjected to HT as rescue in case of cord graft failure, it was noted that 100% of the patients were alive at 40 months of follow-up with a statistically significant difference (p 0.02) compared with those subjected to HT as a first choice.

OS of 70% was reported at 40 months . OS and DFS for children with leukemia was 75% and 40%, respectively. For children with immunodeficiencies it was 65% and 15%, respectively, with a 40-month follow-up