Background: The development of a competent immune system following hematopoietic stem cell transplantation (HSCT) is essential to prevent severe infections. Although neutrophils are the first cells to engraft, in adults neutrophil dysfunction can persist up to 6 months post-transplant. Scant data exists on neutrophil function after pediatric HSCT.
Objectives. Examine neutrophil function following pediatric autologous and allogeneic HSCT.
Methods. Recruited were all patients who underwent HSCT in our Pediatric Hemato-Oncology Department, between 1/1/2012-31/3/2013. Data gathered included demographics, tumor type, staging, previous chemo-radiotherapy, and data on the HSCT procedure. Neutrophils were isolated from 10ml of heparinized blood and examined for: (1)hydrogen-peroxide production (dihydrorhodamine-123-assay), (2)superoxide production (superoxide dismutase-inhibitable reduction of ferricytochrome-c), and (3)chemotaxis (48-well chemotaxis chamber). Functions were examined at engraftment, and then 6 and 10 weeks post-transplant. In case of 3-4 tandem transplantations, as for high-risk medulloblastoma, functions were examined after the last transplantation.
Results. Eighteen patients (11 males and 7 females, mean age±SD, 10.2±5.3 years) underwent HSCT during the study period (5-allogeneic, 8-autologous, and 5 underwent 3-4 tandem autologous transplants each). At engraftment, hydrogen-peroxide was normal in 18/18, superoxide in 6/9, and chemotaxis in 9/9. Six weeks post-transplant, 16 patients remained in the study (1 relapse and 1 graft rejection). Hydrogen-peroxide was normal in 14/14, superoxide in 13/14, and chemotaxis in 9/9. In one patient, superoxide normalized 10 weeks post-transplant. There was no correlation between neutrophil function and the different variables examined.
Conclusions. Hydrogen-peroxide, superoxide, and chemotaxis normalize soon after pediatric HSCT. Larger studies are needed to confirm these results.
