Results of Hematopoietic STEM CELL Transplantation for Primary Immunodeficiencies in Children in Mexico: A Multicentric Report

INTRODUCTION: Hematopoietic stem cell transplantation (HSCT) is the definitive treatment for some primary immunedeficiencies (PID). In 2010 all the pediatric HCT Centers in Mexico formed the “Mexican Association of Pediatric Stem Cell Transplantation and Cellular Therapy”. This represents the first report of the association describing the clinical outcome in HSCT for PID. MATERIAL AND METHODS: Between January 1998 to March 2013 all PID patients in whom a HSCT was performed in 7 pediatric HCT centers in Mexico, were retrospectively analyzed. RESULTS: A total of 57 patients were included. Average age was 29 months (range 2 to 158).  Time from diagnosis until transplantation was 20 months (range 1 to 110). Diagnosis included severe combined immunodeficiency in 30% (n=17), Wiskott-Aldrich Syndrome in 24% (n=14), Griscelli-syndrome in 10% (n=6), Shwachman-Diamonn 2% (n=1), Chédiak-Higashi syndrome in 2% (n =1), others PIDs (in 32% n=18). Graft source included: related bone marrow (RBM) in 7% (n=4), unrelated cord blood in 72% (n=41), and mobilized peripheral blood (PMB), including one haploidentical case, in 21% (n=12). Median cell dose by settings was as follows: in RBM median mononuclear cell dose was 2.34x10⁸/kg and median CD34 cell dose was 2.48x10⁶/kg. In PMB median nucleated cell dose was 8.6 x10⁸/kg and median CD34 cell dose was 6.3x10⁶/kg, whereas in UCB Median Nucleated cell dose was 2.9x10⁸/kg and median CD34 cell dose was 2.1x10⁶/kg. In all but 1 case, GVHD prophylaxis was given. Conditioning regimens included myeloablative in 63% of patients (N=36) and non-myeloablative in 37% (n=21). Engraftment occurred in 63% of patients (n=36). The average time for neutrophil engraftment was 20 days (range from 8 to 54). Fourteen patients (24%) developed an II-IV grades aGVHD, whereas cGvHD was presented only in 7 cases (12%). Transplant related mortality was 26% considering deaths before day 100. The main causes of death were infection and graft failure. Overall survival of all cases was 61%. CONCLUSION: This is the first report of HSCT for PID children in Mexico. The mean source of Hematopoietic stem cells used was UCB (71%) with good results in our population. Early diagnosis and prompt performance of SCT with an optimal donor and conditioning regimen contributed to the favorable outcomes.