Supplementary Material for: Plasma Proteome–Driven Identification of Druggable Immune Regulators of Alopecia Areata, Validated by Transcriptome and Single-Cell Mapping

This study presents a proteome-driven framework to identify druggable immune regulators of alopecia areata (AA), an autoimmune hair-loss disorder. By integrating genetic instruments, lesional transcriptomics, and single-cell immune profiling, researchers identified 206 and 169 AA-associated proteins, with CD28, GZMB, and CD1C as key immune regulators. Single-cell data linked these proteins to local inflammation in AA lesions. The study highlights CD28 as an actionable target, with belatacept, a CD28-blocking biologic, showing potential due to its favorable safety profile. This approach offers a generalizable strategy for discovering autoimmune targets.