Long-term neuroimaging follow-up on an asymptomatic juvenile metachromatic leukodystrophy patient after hematopoietic stem cell transplantation: evidence of myelin recovery and ongoing brain maturation

Early clinical course after hematopoietic stem cell transplantation in children with juvenile metachromatic leukodystrophy

Background

Long-term outcomes of hematopoietic stem cell transplantation (HSCT) in children with juvenile metachromatic leukodystrophy (MLD) have been investigated systematically, while short-term effects of HSCT on the course of the disease remain to be elucidated.

Results

In this study, the clinical course was evaluated over the first 24 months following HSCT, conducted at our center in 12 children with juvenile MLD (mean follow-up 6.75 years, range 3–13.5) and compared with 35 non-transplanted children with juvenile MLD. Motor function (GMFM-88 and GMFC-MLD), cognitive function (FSIQ), peripheral neuropathy (tibial nerve conduction velocity), and cerebral changes (MLD-MR severity score) were tested prospectively.

Seven children remained neurologically stable over a long period, five exhibited rapid disease progression over the first 12 to 18 months after transplantation. In the latter, time from first gross motor symptoms to loss of independent walking was significantly shorter compared with non-transplanted patients at the same stage of disease (p < 0.02). Positive prognostic factors were good motor function (GMFM = 100%, GMFC-MLD = 0) and a low MR severity score (≤ 17) at the time of HSCT.

Conclusions

Our results show that if disease progression occurs, this happens early on after HSCT and proceeds faster than in non-transplanted children with juvenile MLD, indicating that HSCT may trigger disease progression.

Neurological outcomes after hematopoietic stem cell transplantation for cerebral X-linked adrenoleukodystrophy, late onset metachromatic leukodystrophy and Hurler syndrome

Objective

To describe survival and neurological outcomes after HSCT for these disorders.

Methods

Seven CALD, 2 MLD and 2 MPS-IH patients underwent HSCT between 2007 and 2014. Neurological examinations, magnetic resonance imaging, molecular and biochemical studies were obtained at baseline and repeated when appropriated.

Results

Favorable outcomes were obtained with 4/5 related and 3/6 unrelated donors. Two patients died from procedure-related complications. Nine transplanted patients were alive after a median of 3.7 years: neurological stabilization was obtained in 5/6 CALD, 1/2 MLD, and one MPS-IH patient. Brain lesions of the MPS-IH patient were reduced four years after HSCT.

Conclusion

Good outcomes were obtained when HSCT was performed before adulthood, early in the clinical course, and/or from a related donor.

Metachromatic leukodystrophy: Disease spectrum and approaches for treatment

Metachromatic leukodystrophy is an inherited lysosomal disorder caused by recessive mutations in ARSA encoding arylsulfatase A. Low activity of arylsulfatase A results in the accumulation of sulfatides in the central and peripheral nervous system leading to demyelination. The disease is classified in a late-infantile, juvenile and adult onset type based on the age of onset, all characterized by a variety of neurological symptoms, which eventually lead to death if untreated. There is no curative treatment for all types and stages. This review discusses diagnostic process and efficacy of current and possible future therapies such as hematopoietic stem cell transplantation, enzyme replacement therapy and gene therapy. A systematic evaluation regarding the efficacy of hematopoietic stem cell transplantation and a longer follow up period for gene therapy are needed to come to a general conclusion and improve treatment options for metachromatic leukodystrophy.

Hematopoietic SCT: a useful treatment for late metachromatic leukodystrophy

In metachromatic leukodystrophy (MLD), the deficiency of the lysosomal enzyme arylsulfatase A (ARSA) leads to demyelination in the central and peripheral nervous system and ultimately to death. Allogeneic hematopoietic SCT (HSCT) is currently the only treatment for adult and late-onset juvenile MLD, although it is still in question because of insufficient follow-up. We wanted to determine whether HSCT could halt the progression of adult and late-onset juvenile MLD. Four treated unrelated patients and three untreated siblings were included in the study, and followed regularly for up to 18 years after transplantation. The patients were assessed from clinical examination, ARSA enzyme levels, magnetic resonance imaging of the brain and neuropsychological and neurophysiological tests. In the treated patients, ARSA levels were normal up to 18 years after transplantation. The parameters evaluated stabilized and remained stable after a latency period of 12-24 months. Two patients live normal lives, partially in a protected environment. The other two patients stabilized at a low cognitive and functional level. One of the controls is demented, one is in a vegetative state and one died. We conclude that, in comparison with their untreated siblings, HSCT halted the progression of the disease in our treated patients.

Clinical proton MR spectroscopy in central nervous system disorders

A large body of published work shows that proton (hydrogen 1 [(1)H]) magnetic resonance (MR) spectroscopy has evolved from a research tool into a clinical neuroimaging modality. Herein, the authors present a summary of brain disorders in which MR spectroscopy has an impact on patient management, together with a critical consideration of common data acquisition and processing procedures. The article documents the impact of (1)H MR spectroscopy in the clinical evaluation of disorders of the central nervous system. The clinical usefulness of (1)H MR spectroscopy has been established for brain neoplasms, neonatal and pediatric disorders (hypoxia-ischemia, inherited metabolic diseases, and traumatic brain injury), demyelinating disorders, and infectious brain lesions. The growing list of disorders for which (1)H MR spectroscopy may contribute to patient management extends to neurodegenerative diseases, epilepsy, and stroke. To facilitate expanded clinical acceptance and standardization of MR spectroscopy methodology, guidelines are provided for data acquisition and analysis, quality assessment, and interpretation. Finally, the authors offer recommendations to expedite the use of robust MR spectroscopy methodology in the clinical setting, including incorporation of technical advances on clinical units.

Juvenile metachromatic leukodystrophy 10 years post transplant compared with a non-transplanted cohort

Metachromatic leukodystrophy (MLD) is a rare inborn error of metabolism leading to severe neurological symptoms and early death. Hematopoietic SCT (HSCT) is considered a treatment option, but results are inconsistent and comparison with natural history is practically missing. We compare a girl with juvenile MLD 10 years after allogeneic HSCT not only with her untreated sister, but also with a large cohort of untreated patients. The girl received HSCT at the age of 5 years when first motor signs appeared. Over 10 years she was stable with respect to her clinical course and gained cognitive abilities. Magnetic resonance imaging (MRI) showed clear regression of white matter changes and magnetic resonance spectroscopy (MRS) demonstrated a reversal of the initial choline increase and N-acetyl-aspartate (NAA) decrease. Only axonal demyelinating neuropathy showed some progression. Her gross motor function and MRI-scores were clearly better compared with her sister and the cohort of untreated patients. Difference to her sister became apparent only 4 years after HSCT. We conclude that HSCT, early in the course of disease, can lead to stabilization of juvenile MLD with a course clearly different from the natural history. HSCT may prevent disease progression, if performed sufficient time before loss of walking, which typically initiates rapid deterioration.