Large volume peripheral blood progenitor cell (PBPC) harvest in 27 pediatric solid tumor patients weighing less than 20 Kg

Abstract

9061 While PBPC collection has become a safe and common procedure in adults, fewer reports exist about its efficacy and safety in low weight pediatric patients. PBPC harvest might be difficult in this patient population and extracorporeal separator line priming with red blood cells is usually required to improve hemodynamic stability and effectiveness of the collection. We present our experience in 27 children (11 females, 16 males) weighing less than 20 kg and autografted between May 2001 and December 2005. Median age and weight at the time of apheresis were 2.7 years (0.7 to 8) and 14.3 kg (9.7 to 20), respectively. Diagnosis were neuroblastoma in 15, brain tumor in 10, and others in 2. Harvest of PBPC started after mobilization with G-CSF 10 ug/kg/day SC for 4 days. A double lumen (Arrow 7Fr) central venous catheter was surgically placed under sedation in the OR. Collections were performed using a COBE Spectra separator primed with irradiated, white cell-depleted and CMV-negative packed red cells. A median of 2 (1 to 7) procedures were performed, resulting in the harvest of 12.9 (3.6–33.1) × 108/kg mononuclear cells and 4.98 (2.33–12.69) × 106/kg CD34 (+) cells. The apheresis were performed in the presence of the parents and did not require sedation. Only 1 patient had as side-effect perioral paresthesias with normal serum calcium. No patient had vasovagal reactions. A median platelet count reduction of 66% was observed, comparing pre and post apheresis values. All patients completed the procedure with a median of 71.800 platelets (25.000 to 152.000) and a median hemoglobin of 10.8 g/dl (8.2 to13.6). All children were successfully transplanted with myeloid engraftment (ANC >500 × 109/L) at a median of 11 days (9 to 14) and independence from platelet transfusions (> 20,000x × 109/L) at a median of 17 days (8 to 39) after PBPC infusion. Median of hospitalization days was 23 (18 to 42). We conclude that PBPC harvesting using large volume continuous flow cell separation was safe, even in this low-weight pediatric population. This procedure shortens the total number of apheresis, providing an adequate number of CD34 + cells, resulting in satisfactory hematological recovery and duration of hospitalization. No significant financial relationships to disclose.