When we compared CCR2 immunoreactivity in WM and GM of control subjects, MS patients without hippocampal lesions and MS patients with active or inactive lesions we found that the number of CCR2 positive cells was significantly higher in hippocampal WM compared to GM of MS patients without hippocampal lesions (Wilcoxon Signed Rank test, p = 0.03). Here, CCR2 is linked to myeloid sarcoma.