High white blood cell concentration in the peripheral blood stem cell product can induce seizures during infusion of autologous peripheral blood stem cells.

Seizures as a complication of the infusion of autologous peripheral blood stem cells (PBSC) are rare. Seizures during infusion of autologous PBSC in 3 of our patients prompted us to review our cell therapy and cytapheresis protocols and procedures. We retrospectively analyzed 159 adult patients collected between January 2006 and July 2009. Patients were collected on either the COBE Spectra (Caridian BCT, Lakewood, CO) cell separator (n = 85) or Fresenius AS (Fresenius Kabi AG, Bad Homburg, Germany) 104 cell separator (n = 74) and mobilized with granulocyte-colony stimulating factor (G-CSF) alone (n = 47), G-CSF and Plerixafor (n = 36), or G-CSF and chemotherapy (n = 76). Patient characteristics (including age, weight, number of collections, volume processed, disease type, and mobilization strategy) did not differ significantly between the COBE and Fresenius cohorts, and adverse effects from infusion were similar except for 3 of 159 patients who experienced seizures upon infusion of PBSC; all 3 were collected on the COBE and had PBSC product white blood cell (WBC) counts of 590 × 10(3)/μL or above. We prospectively correlated WBC counts midcollection, with final WBC counts to identify products with high WBC concentration during cytapheresis. Fifty-one patients had 66 cytapheresis procedures using the COBE, with WBC counts midway and at the end of collection of 287 × 10(3) ± 150/μL and 273 × 10(3) ± 144/μL, respectively. Mid-WBC therefore correlated with WBC at the end of the collection. Finally, we prospectively collected mid-WBC from 65 patients who underwent 80 PBSC collections between June 2009 and January 2010 to identify products with midcollection WBC concentration >450 × 10(3)/μL. In those cases, additional autologous plasma was collected at the time of collection to dilute the final product before cryopreservation. Patients who received diluted products experienced no delays in engraftment and no additional seizure episodes occurred.