G-CSF-mobilized haploidentical peripheral blood stem cell transplantation in children with poor prognostic nonmalignant disorders.

Haploidentical hematopoietic stem cell transplantation (HSCT) is currently one of the alternative curative treatment options for some nonmalignant but also for malignant diseases. However, concerns regarding its safety cause delays in time and a successful outcome. Between 2000 and 2005, twenty-one children with poor prognostic nonmalignant disorders, 13 boys and 8 girls, with a median age of 12 months, underwent 28 haploidentical peripheral HSCT. Immunomagnetic bead depletion device (CliniMACS) was used for indirect T-cell depletion. Indications for transplant were severe combined immunodeficiency (n=16), osteopetrosis (n=2), MDS (n=1), amegakaryocytic thrombocytopenia (n=1), and aplastic anemia (n=1). Five patients (24%) had lung infection at the time of transplantation. The patients received a median of 25.67 x 10(6) G-CSF-mobilized peripheral CD34(+) progenitor cells and a median of 4.19 x 10(4) T-lymphocytes per kilogram of body weight with a T-cell depletion rate of median 4.59 logs. The rate of total engraftment was 66.6%. Median times for leukocyte and platelet engraftment were 14 and 16 days, respectively. The 6-year projected survival was 32% for all patients and 29.76% for patients with severe combined immunodeficiency (SCID). The rates of transplant-related mortality, graft failure, and severe GvHD were 14.2, 33.4%, and 8.3%, respectively. Infection was the main cause of death. The poor outcome may be explained with the poor prognostic factors of our patients such as the type of SCID in most cases (T-B- SCID), the median age over 6 months and the presence of lung infection in some children at the time of transplantation.