Disease severity impacts plerixafor-mobilized stem cell collection in patients with sickle cell disease

Blood Adv. 2021 May 11;5(9):2403-2411. doi: 10.1182/bloodadvances.2021004232.


Recent studies suggest that plerixafor mobilization and apheresis in patients with sickle cell disease (SCD) is safe and can allow collection of sufficient CD34+ hematopoietic stem cell (HSC) collection for clinical gene therapy applications. However, the quantities of plerixafor-mobilized CD34+ cells vary between different SCD patients for unknown reasons. Twenty-three participants with SCD underwent plerixafor mobilization followed by apheresis, processing, and HSC enrichment under a phase 1 safety and efficacy study conducted at 2 institutions. Linear regression or Spearman's correlation test was used to assess the relationships between various hematologic and clinical parameters with total CD34+ cells/kg collected. Median CD34+ cells/kg after 2 or fewer mobilization and apheresis cycles was 4.0 × 106 (range, 1.5-12.0). Similar to what is observed generally, CD34+ yield correlated negatively with age (P < .001) and positively with baseline (P = .003) and preapheresis blood CD34+ cells/µL (P < .001), and baseline white blood cell (P = .01) and platelet counts (P = .03). Uniquely for SCD, CD34+ cell yields correlated positively with the number of days hydroxyurea was held (for up to 5 weeks, P = .01) and negatively with markers of disease severity, including hospitalization frequency within the preceding year (P = .01) and the number of medications taken for chronic pain (P = .002). Unique SCD-specific technical challenges in apheresis were also associated with reduced CD34+ cell collection efficiency and purification. Here, we describe factors that impact plerixafor mobilization success in patients with SCD, confirming known factors as described in other populations in addition to reporting previously unknown disease specific factors in patients with SCD. This trial was registered at www.clinicaltrials.gov as #NCT03226691.

Publication types

  • Clinical Trial, Phase I
  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anemia, Sickle Cell* / therapy
  • Benzylamines
  • Cyclams
  • Granulocyte Colony-Stimulating Factor
  • Hematopoietic Stem Cell Mobilization
  • Heterocyclic Compounds*
  • Humans
  • Severity of Illness Index


  • Benzylamines
  • Cyclams
  • Heterocyclic Compounds
  • Granulocyte Colony-Stimulating Factor
  • plerixafor

Associated data

  • ClinicalTrials.gov/NCT03226691