CD4 and chronic kidney disease: Similar to CD4+ T cells, we observed a decreased frequency of naïve CD8+ T cells in CKD patients, while that of ESKD patients was close to HC (HC: 19.2 ± 11.1% vs. CKD: 10.8 ± 9.1% vs. ESKD: 14.83 ± 11.0%) (Figure 4A).