While at least 88% of Iba1 + cells expressed TSPO in lesions < 4 weeks old, the percentage expressing TSPO was as low as 13% in lesions > 6 months old, consistent with studies in MS demonstrating a decline in the percentage of TSPO contributed by Iba1 + cells in chronic and inactive lesions [13, 21]. Here, AIF1 is linked to myeloid sarcoma.