Results from double immunofluorescent staining demonstrated that p75NTR could hardly be observed in CD206-positive cells (Supplementary Figure 1A) but was highly expressed in the CD16/32-positive cell population in the perilesional area (Figure 3A), indicating p75NTR upregulated in M1 but not M2-like cells after mTBI. Here, MRC1 is linked to concussion.