Recombinant fusion proteins of PD-L1 and adenoviruses expressing PD-L1 have shown reduced inflammation severity in various animal models, including rheumatoid arthritis, colitis, psoriasis, and ARDS 11-15, underscoring the involvement of the PD-1-PD-L1 axis in other immune regulatory capacities 16, 17. This evidence concerns the gene CD274 and rheumatoid arthritis.