Alopecia areata: an autoimmune insult, molecular insights, and therapeutic horizons

Alopecia areata (AA) is a relapsing autoimmune disease characterized by non-scarring loss of hair following the collapse of immune privilege of the anagen hair follicles. This review summarizes recent molecular findings linking follicular stress to an atypical cytotoxic response, with special emphasis on the role of CD8 + NKG2D+ T cells, stress-induced ligands (MICA/ULBPs), and a Th1 cytokine circuit triggered by IFN-γ and IL-15, which communicates via the JAK/STAT pathway. We present new evidence that oxidative stress and mitochondrial dysfunction can enhance immune activation and may follow disease activity, generating the prospect of redox- and mitophagy-based adjunctive interventions. In addition to mechanisms, we discuss genetic susceptibility loci and high-throughput profiling, such as transcriptomics and proteomics, and describe how integrated multi-omics can be used to assist endotyping, prognostication, and biomarker-sensitive treatment selection. In treatment, AA is moving toward narrow-based agents rather than general immunosuppression and local agents. The efficacy standard is now set by JAK inhibitors, with baricitinib supported by landmark phase 3 studies demonstrating significantly increased scalp regrowth compared to placebo, and newer selective JAK inhibitors and IL-15-based or other immune checkpoint biologics are under development. Combination regimens based on immune signature, real-world safety surveillance, and strategies to achieve long-term immune tolerance and reestablish follicular immune privilege over short-term suppression are the key priorities in the future.