In acne vulgaris, keratinocyte-secreted chemokines, including CCL2 and CCL5, TREM2+ macrophage-secreted chemokines, such as CXCL16 and SPP1 (37), and sebocyte-secreted chemokines, like CXCL8 (13), have the ability to attract immune cells to the acne region. Here, TREM2 is linked to acne.