A scRNA-seq study reported a significant decline in MAIT cells in subjects with periodontitis (20) The scRNAseq data revealed an upregulation of nucleotide oligomerization domain (NOD)−like receptor signaling pathways, apoptosis, IL-17 signaling, and TNF signaling in MAIT cells from periodontitis subjects (69). The gene discussed is IL17A; the disease is periodontitis.