ADPRH (ADP-ribosylarginine hydrolase) is a hydrolase that catalyzes the removal of mono-ADP-ribose groups attached to arginine residues on proteins, functioning as the opposing arm of an ADP-ribosylation cycle 1. The enzyme requires metal ion cofactors including potassium and magnesium for catalytic activity 2. ADPRH is broadly expressed across mammalian tissues, with particularly high levels in brain, spleen, and testis, regulated through housekeeping-gene-like promoter elements 1. Clinically, ADPRH dysregulation associates with immunological dysfunction and malignancy. High ADPRH expression in low-grade glioma (LGG) independently predicts poor overall and progression-free survival 3. ADPRH modulates CD8+ T cell functions and correlates strongly with tumor immune infiltrating cell composition 3. The enzyme operates within multiple oncogenic signaling pathways including P53, KRAS, IL6/JAK-STAT3, and TNF-beta signaling, suggesting roles in cancer progression 3. Additionally, ADPRH expression in glioma macrophages associates with worse prognosis and altered immune microenvironment characteristics 4. Beyond malignancy, ADPRH dysfunction links to primary immunodeficiencies including agammaglobulinemia and autosomal recessive hyper-IgE syndrome, highlighting its importance in adaptive immune regulation. These findings position ADPRH as both a potential prognostic biomarker and therapeutic target in malignant and immunological diseases.