In the liver, hepatocytes express both IL-10R2 and IL-22R1; Many diseases, such as psoriasis, graft-versus-host disease, liver and pancreas damage, ulcerative colitis and tumours are closely related to the IL-22 -IL-22R1 system, this point has been demonstrated in the experimental data in recent years 12. Here, IL22RA1 is linked to graft versus host disease.