Somatostatin Expression in Human Hair Follicles and Its Potential Role in Immune Privilege

The study investigated the immune privilege (IP) of human hair follicles (HF), focusing on the expression of somatostatin (SST) and its potential role. Using various methods, including qPCR, immunohistology, ELISA, and flow cytometry, researchers found that HF cells did not promote allogeneic PBMC proliferation or IFNγ production. They observed significant downregulation of Class I and II HLA alleles and upregulation of immunoregulatory genes in the HF. SST was notably upregulated and strongly expressed in the HF outer root sheath, with cultured sheath cells secreting SST. SST reduced IFNγ secretion in PBMCs, and SST antagonists increased IFNγ secretion when added to PBMCs cocultured with HF cells. These findings suggested that SST might contribute to the IP of HFs.