ABCD2 and X-linked adrenoleukodystrophy: Although these observations cannot be directly translated to human perivascular or parenchymal macrophages or activated microglia cells in brain lesions of an X-ALD patient, the results are encouraging for therapeutic strategies aiming at upregulating expression of ABCD2. The use of Abcd1 and Abcd2 single and double-deficient macrophages provides a unique model to discriminate whether ABCD2 is necessary for any observed effects of treatment in the macrophage lineage.