Chronic Inflammation and T Cell Zeta-Chain Downregulation in Hemodialysis Patients

Abstract

Background: Clinical and experimental data indicate a deficient immune response in hemodialysis (HD) patients. ζ-Chain phosphorylation is an early and central event in the process that follows antigen recognition by the T cell antigen receptor (TCR). T cell ζ-chain is downregulated in many chronic inflammatory states, such as cancer, autoimmune disease and chronic infection. HD is also characterized as a chronic inflammatory state. The aim of the present study was to evaluate T cell ζ-chain expression in HD patients. Patients and Methods: Thirty-three stable HD patients and 30 healthy volunteers were enrolled into the study. T cell count, the percentage of ζ-chain-positive T cells, as well as T cell ζ-chain mean fluorescence intensity (MFI) were evaluated with flow cytometry. The inflammatory markers C-reactive protein, interleukin-6 and tumor necrosis factor-α were measured in the serum by means of ELISA. Results: All the evaluated markers of inflammation were increased in HD patients. In these patients, T cell ζ-chain MFI was decreased. CD3-Ε MFI did not differ between the two groups indicating that among the TCR complex constituents, ζ-chain is selectively downregulated. Conclusions: HD is a state of chronic inflammation. Like in other pathological chronic inflammatory conditions, T cell ζ-chain is downregulated in HD patients. Since ζ-chain plays a key role in the transduction of the signal that follows antigen recognition by the TCR, its downregulation could be responsible for the deficient cellular immune response observed in HD patients.