14800-DvRappard

94 Chapter 6 ataxia. MRI showed extensive white matter abnormalities. Diagnosis of juvenile MLD was confirmed by low ASA activity; ARSA mutation analysis revealed c.830delTCinsAA, p.(Ile277Lys) and c.1277C>T, p.(Pro426Leu). Total IQ was 74. HCT was performed with a fully matched unrelated male cord blood donor. Despite fast successful engraftment and full donor chimerism, the disease rapidly progressed. She died one year after diagnosis. Patient 3 (female) was 26 months old when diagnosed with late-infantile MLD because of motor regression, confirmed by absent ASA activity and mutations c.245C>T, p.(Pro82Leu) and c.287C>T, p.(Ser96Phe) in ARSA . MRI showed extensive white matter abnormalities with sparing of the direct subcortical white matter and the typical hypointense stripes within the abnormal white matter. She continued to deteriorate and died three years after diagnosis from disease progression. Patient 4 (NBB5505) died at age 3 years from late-infantile MLD, after having been diagnosed at age 22 months because of delayed acquisition of independent walking, with low ASA activity and mutations c.841G>T, p.(Asp281Tyr) and c.1004A>T, p.(Asp355Val) in ARSA . He deceased because of disease progression in the context of feeding difficulties and a respiratory infection. Patient 5 (NBB3308) died at age 21 years, patient 6 (NBB1144) at age 12 years, patient 7 ( NBB5381) at age 7 years and patient 8 (NBB5509) at age 6 years. Regarding these patients, no further information was available. Histopathology In the two transplanted patients, donor macrophages had successfully reached the brain. Histopathology showed metabolically competent macrophages able to degrade sulfatides to cholesterol (orthochromatic and Oil red O-positive cells) next to macrophages loaded with sulfatides (metachromatic cells). FISH studies for X and Y chromosomes confirmed the presence of donor cells in the transplantedbrains (figure 2). In most WM areas of transplanted patients, the number of CD45-positive activated microglia/macrophages was greatly elevated compared to untreated individuals (figure 3). Notably, the total number of microglia/macrophages, as assessed by CD68, did not significantly differ in treated versus untreated patients, suggesting that HCT is associated with a more robust microglia/macrophage activation rather than with increased proliferation of these cells. We then questioned whether HCT had an effect on the microglia/macrophages phenotype. In vitro, these cells can be polarized towards opposite states of a spectrum, one being pro-inflammatory (M1) and the other anti- inflammatory (M2). In transplanted patients, macrophage expression of M2-associated proteins was significantly higher than in untreated patients in all WM areas examined.