Chronic inflammation and CD16+ natural killer cell zeta-chain downregulation in hemodialysis patients

Background: Natural killer (NK) cell activity is decreased in hemodialysis (HD) patients. Zeta-chain phosphorylation is an early event that follows the triggering of some NK cellactivating receptors. NK cell zeta-chain is downregulated in patients with cancer due to chronic inflammation. HD is also a chronic inflammatory state. NK cell zeta- chain expression in HD was evaluated. Patients and Methods: Thirty-three HD patients and 30 healthy volunteers were enrolled into the study. The CD3-CD16+ subpopulation was examined, since it corresponds to 90% of all NK cells and has the highest cytotoxicity. NK cell count and zeta- chain mean fluorescence intensity were evaluated with flow cytometry. The inflammatory markers C- reactive protein, IL-6 and tumor necrosis factor-alpha were measured with ELISA. Results: The inflammatory markers were increased in HD patients. NK cell count did not differ between HD patients and healthy volunteers. NK cell zeta- chain mean fluorescence intensity was decreased in the patient group. Conclusions: Chronic inflammation could be responsible for the NK cell zetachain downregulation in HD patients, contributing to the decreased NK cell activity. Copyright (c) 2008 S. Karger AG, Basel.