RNF215 is a ring finger ubiquitin ligase protein located on chromosome 22 that functions as a negative regulator of innate immune signaling. RNF215 inhibits type I interferon (IFN) production by interacting with NF-κB p65 and repressing its accumulation at the IFNB1 promoter, thereby dampening antiviral responses 1. This regulatory mechanism is clinically relevant to autoimmune diseases: RNF215 expression negatively correlates with type I IFN levels in systemic lupus erythematosus patients, suggesting dysregulation contributes to aberrant IFN-driven pathology 1. Genome-wide association studies have identified RNF215 as a novel susceptibility locus for multiple autoimmune conditions, including juvenile idiopathic arthritis (oligoarticular and RF-negative polyarticular subtypes) 2 and sarcoidosis across European and African ancestries 3. Beyond autoimmunity, RNF215 has been identified as part of a radiotherapy-related methylation signature associated with head and neck squamous cell carcinoma prognosis 4. These findings suggest RNF215 serves as a critical immunological checkpoint that, when dysregulated, contributes to both autoimmune disease susceptibility and potentially affects cancer treatment outcomes.