What this study looked at
Metachromatic leukodystrophy (MLD) is a lysosomal storage disorder caused by reduced activity of the enzyme arylsulfatase A. This was the first study to examine, in donated brain tissue, how haematopoietic stem cell transplantation actually works in people with MLD, comparing autopsy tissue from transplanted and non-transplanted patients with age-matched controls.
Key takeaways
- In the transplanted patients, metabolically competent donor macrophages carrying arylsulfatase A were found distributed throughout the white matter.
- These donor macrophages tended to take on an anti-inflammatory phenotype, and transplanted patients had more oligodendrocytes and evidence of remyelination.
- Contrary to the prevailing hypothesis, the study found no enzymatic cross-correction of the patients' own astrocytes and oligodendrocytes, pointing instead to a neuroprotective role for the donor cells.
Why it matters
The findings suggest that immune modulation, alongside metabolic correction, is important to how transplantation helps in MLD, which could be exploited to improve future treatment.
