Development of Psycho-Intellectual Performances of Transplanted Sickle Cell Disease Patients: a Prospective Study From Pre-Transplant Period to 5 Years After HSCT.

Allogeneic hematopoietic stem-cell transplantation (HSCT) is the only curative treatment for sickle cell disease (SCD). Cerebral vasculopathy with or w/o stroke or ischemic lesion was the principal indication for transplantation. All the patients received grafts from a sibling donor after a myeloablative conditioning regimen (Bu 16mg/kg; cyclophosphamide 200mg/kg; ATG). These children could present impaired neuro-psychological development related to different causes as frequent impaired familial socio-economic situation, previous cerebral lesions and aggressive therapy like HSCT. Then, it appears very interesting to explore their intellectual capacities before and after transplantation.

We conduct a prospective longitudinal study from 1992 to 2009 in all SCD patients who underwent HSCT before 2006. Evaluations were performed by Wechsler scales, either WISC (Wechsler Intelligence Scale for Children) III and IV (before and after 2003), for patients older than 6 years or by WPPSI (Wechsler Preschool and Primary Scale of Intelligence) R and III (before and after 2002), for patients younger than 6 years of age. The more recent scale versions evaluate four different indices - Verbal Comprehension (VCI), Perceptual Reasoning (PRI), Working Memory (WMI) and Processing Speed (PSI) that lead to calculate full scale Intellectual Quotient (IQ).

15 out of 18 transplanted SCD patients were evaluated before transplantation, 36 and 48-60 months after HSCT (1 pt died during HSCT procedure; 1 was too young for pre-HSCT evaluation; 1 refused tests). There were 8 females and 7 males (median age 8.9y, range 4.7-13.3). All but 1 were from sub-saharian Africa and have lived in France with their family for several years. All patients but 2 have experimented ischemic stroke before HSCT. The 2 remaining pts presented with severe cerebral vasculopathy. Mean and median full scale IQ were 85±15 and 87, 87±15 and 94, 95±12 and 94 before, 36 months and 48-60 months after HSCT, respectively. Details of progression of different indices are indicated in figure 1.

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Mean progression of different indices through 5 years

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Mean progression of different indices through 5 years

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At pre-HSCT evaluation, mean full scale IQ is 85, i.e.”low average”. This relative poor result could be related to impairment of PSI that reflects frequent grapho-motor abnormalities related to previous stroke experimented by almost all patients.

At 3 years post-HSCT, all indices including IQ increase. Only PSI was decreased, this observation being potentially related to previous stroke–as before HSCT–and to the depression frequently experimented by transplanted patient after “acute phase” of this procedure, when disease is cured.

At 5 years after HSCT, mean full scale IQ increases dramatically (+10 points) since all other indices have progress, particularly PSI. However, PSI remains the most impaired one.

At the end of follow-up, patients improve their physical and psychological well-being. This allowed them to build project for future and to manifest the desire of becoming adult.

BMT in this cohort of children with SCD and severe cerebral vasculopathy is associated to improvement of performances measured by Wechsler scale.

No relevant conflicts of interest to declare.