Active hippocampal WML showed significantly more CCR2 immunopositive in the WM border (256.6 ± 90.2 cells/mm2) compared to WM in control hippocampi, and WM in myelinated MS hippocampi (9.1 ± 8.5 cells/mm2) and the WML and border of inactive hippocampal lesions (ANOVA, F = 19.77, p < 0.001; Tukey HSD, p < 0.005 for all comparisons). Here, CCR2 is linked to myeloid sarcoma.