[Gatsky]

Reading the paper [1], the genetically modified stem cells overexpress the ARSA enzyme. This seems to create a ‘bystander effect’ which increases the total body enzymatic activity above some critical threshold sufficient to arrest the disease process. Myeloid cells associated with neuronal structures are probably critical to this benefit. A standard bone marrow transplant doesn’t reach this threshold, and has demonstrated poor efficacy in early onset disease.