Based on immune cell correlation analysis, these core genes were positively correlated with substantial immune cell infiltration in patients with RA and CD, of which Regulatory.T.cell, MDSC, Macrophage, Gamma.delta.T.cell, Activated.dendritic.cell, and Activated.CD4.T.cell showed a high positive correlation with all core genes simultaneously in RA and CD, again suggesting that these genes are involved in multiple immune-related mechanisms in the disease process. This evidence concerns the gene CD4 and rheumatoid arthritis.