It is reported that genetic polymorphisms of cytokines have been associated with variations in the level of transcription and expression of cytokines that can exert activities in human diseases.28Combined with our conclusion that IL‐27 gene polymorphism is associated with HIV infection and its disease progression, we studied the difference in the expression of serum IL‐27 levels in different genotypes of IL‐27, thus exploring the relationship between genetic polymorphism of cytokines, expression of cytokines and diseases. The gene discussed is IL27; the disease is HIV infectious disease.