Abstract
Keloids are abnormal scars that grow excessively due to increased fibroblast activity and collagen buildup. They spread beyond the original wound and often come back even after treatment. To find useful biomarkers and treatment targets, we studied immune cells in both blood and scar tissue from a hospital-based group that included 104 keloid patients, 512 healthy individuals, and 100 patients with other scar or inflammatory skin diseases.
Using flow cytometry and single-cell RNA sequencing, we found that CD8+ T cells, which normally help destroy abnormal cells, were greatly reduced in the blood and scar edges of keloid patients. The remaining CD8+ T cells in keloid tissue showed high levels of an inhibitory receptor called NKG2A/CD94, which weakens immune activity. This was linked to increased levels of soluble HLA-E (sHLA-E) in the blood.