Knockdown of ORM1 or CCR5 in CIA rats reduced arthritis index, while alleviating cartilage erosion, inflammatory infiltration and synovial hyperplasia of ankle joints.<h4>Conclusions</h4>ORM1 deficiency suppresses the aggressive phenotype of FLS to reduce RA progression by downregulating CCR5. The gene discussed is CCR5; the disease is arthritic joint disease.