Using a new single-cell analysis technology that identifies the types, as well as the location, of individual cells in a skin biopsy, the researchers found a previously unobserved type of macrophage – TREM2 – in hair follicles and around the sebaceous glands in acne lesions. They then identified the process by which TREM2 metabolizes lipids, digests bacteria and facilitates the skin infection. Until now, just two major types of macrophages – M1, which kills some types of bacteria, and M2, which acts as an anti-inflammatory – had been identified in acne.
