PRF1 and chronic kidney disease: Further, incubation with HSP60 and HSP70 increased the expression of IFN-γ (P = 0.004 and P = 0.002), perforin (P = 0.0006 and P = 0.002), and granzyme B (P = 0.02 and P = 0.009) in CD4+CD28null T-cells in CKD subjects (Figure 3).