VNN2 (vanin 2) is a membrane-bound amidohydrolase that specifically hydrolyzes D-pantetheine to recycle pantothenic acid (vitamin B5) and release cysteamine 1. The protein serves as a distinctive cell surface marker for specific immune cell populations, particularly being highly expressed on healthy myeloid-derived suppressor cells (Mo-MDSC) and certain monocyte subsets 2. VNN2+ monocytes exhibit unique functional characteristics, showing decreased HLA and CD62L expression but increased ICAM1, ITGAM, and chemokine receptor expression compared to VNN2- cells 3. The protein demonstrates clinical significance across multiple conditions: reduced VNN2+ monocytes correlate with primary Sjögren's syndrome and may serve as a diagnostic marker 3, while VNN2 expression is associated with chemoresistance in pediatric B-cell precursor acute lymphoblastic leukemia 4. Additionally, VNN2 shows upregulated expression in inflammatory conditions like periodontitis, correlating with disease severity and neutrophil-related pathological processes 5. In reproductive biology, VNN2 is regulated by gonadotropins in bovine ovarian follicles prior to ovulation 6. The protein's involvement in stress response and tissue repair mechanisms is suggested by its presence in circulating extracellular vesicles following intracerebral hemorrhage 7.