CD28 and diffuse large B-cell lymphoma: B7- CD28 family gene expression was negatively correlated with T cell activation involved in immune response (GO:0002286), T-helper 1 type immune response (GO:0042088), and T-helper 2 type immune response (GO:0042092) (Supplementary Figure 5), indicating that the B7-CD28 family generally inhibits T cell immunity in DLBCL.