According to the results of functional analysis, both GO and KEGG analysis were tied to the immune system, such as “leukocyte cell–cell adhesion,” “T-cell activation,” “MHC protein complex,” “MHC class II protein complex,” “integrin binding,” “chemokine receptor binding,” “rheumatoid arthritis,” “chemokine signaling pathway,” “antigen processing and presentation,” and so on, suggesting a high correlation between the development of renal tubular injury in DN and the infiltration differential of immune cells. Here, HLA-C is linked to rheumatoid arthritis.