Aire functions in negative selection of self-reactive TCR during lymphocyte development through activation of tissue-restricted antigen, or TRA. This occurs specifically in the mTEC cells of the thymus, where Aire expression is generally restricted to (1) Tolerogenic signaling through Aire in the periphery was previously suggested (2). We measured total transcription in T cells subsets to discover T-cell lineage-specific gene expression. We describe here biologically significant Aire expression in Th17 cells. The difference in amount of Aire produced in the T cell when comparing naive T cells to Th17-type T cells was large, among the largest transcriptome-wide, with lineage specific enrichment of Aire in Th17 cells. The data suggested in sum that negative selection or tolerizing function occurs in the periphery, through lineage-specific expression of Aire in Th17 cells (3).