The study examined the relationship between kidney function and T lymphocytes and mitochondrial parameters in 802 patients with chronic kidney disease (CKD) in stages 1 to 5. Results showed that in advanced disease stages (stages 3-5), there were fewer CD45+, CD3+, CD4+, and CD8+ T cells compared to stages 1-2. In stage 5, lymphocyte percentage was lower and neutrophil percentage was higher. Mitochondrial alterations in stages 3-5 included decreased cells with low mitochondrial membrane potential. After adjustment for other factors, kidney function (eGFR) was independently associated with changes in mitochondrial membrane potential in CD3+ and CD8+ T cells. The study confirmed that more advanced CKD stages are associated with reduced T lymphocyte counts and alterations in mitochondrial parameters.