CD28 and chronic kidney disease: We applied flow cytometry to determine total, CD4<sup>+</sup>, CD8<sup>+</sup>, CD28<sup>-</sup> T-lymphocytes, Natural killer cells (NK) and regulatory T-lymphocytes (Tregs), in peripheral blood of 56 patients with CKD-V, 207 patients on hemodialysis (HD), 149 recently transplanted (rKTx), 26 lKTx patients and 49 healthy volunteers as a control group (CG).