What are the restrictions to stem cell transplantation (SCT) for sickle cell disease (SCD)?

Updated: May 12, 2021
  • Author: Joseph E Maakaron, MD; Chief Editor: Emmanuel C Besa, MD  more...
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To date, HSCT has been considered indicated in SCD patients younger than 16 years with HbSS or HbS–β-0 thalassemia who have severe disease, as evidenced by one or more of the following [102] :

  • Stroke (or central nervous system event lasting longer than 24 hours)
  • Recurrent acute chest syndrome
  • Recurrent severe crisis pain (>2 episodes/y for several years)
  • Recurrent priapism
  • Impaired neuropsychological function with evidence of cerebral infarction on imaging studies
  • Sickle cell nephropathy (glomerular filtration rate 30–50% of predicted normal)
  • Stage I or II sickle lung disease
  • Bilateral proliferative retinopathy and major visual impairment in at least one eye
  • Osteonecrosis of multiple joints
  • Red cell alloimmunization with more than 2 antibodies during long-term transfusion therapy

HSCT for SCD has historically been limited to patients with an HLA-identical sibling donor. However, only 18% of patients with SCD have an HLA-matched sibling who does not have SCD. This has spurred the exploration of other donor options. Only 16% to 18% of African Americans have a full HLA-matched unrelated donor option in the national donor pool, but partial-matched unrelated donors, half-matched (ie, haploidentical) donors, and partial-matched cord blood have all been used. [103, 65]

Unrelated donor transplants are associated with a higher rate of GVHD than HLA-matched sibling donor transplants, but use of reduced-intensity or nonmyeloablative conditioning regimens in these cases has reduced the risk of GVHD and graft failure otherwise seen with non–fully matched donors. [64, 65] A reduced-intensity conditioning regimen was also used in a successful pilot study of HSCT in adolescents and young adults (age 17-36 years). [104]

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