Akademik Veri Yönetim Sistemi
39. Ulusal Nefroloji Kongresi, Antalya, Türkiye, 9 - 13 Kasım 2022
Hyponatremia or hypotonicity is characterized by a plasma sodium concentration of less than 135 mEq/L as a result of increased relative and absolute water concentration in the extracellular environment. Although the effects of the hypoosmolar environment on astrocytes are known, the effects on the immune system remain a mystery. The aim of this study was to demonstrate the effects of hypoosmolar milieu due to hyponatremia on the immune system.
Twenty patients over 18 years of age who have hyponatremia that could be corrected by water restriction were included. Serum and urine osmolarities were assessed in all patients. Peripheral blood samples were obtained from all patients before and after treatment. The subsets of lymphocytes, monocytes, and granulocytes were examined by flow cytometer. Programmed cell death protein-1 (PD-1) is one of the inhibitory receptors associated with T-cell exhaustion, and these cells are characterized by decreased cytokine production and proliferative capacity. PD-1+ B-cells are known to have a regulatory effect on lymphocyte activation and proliferation. In our study, PD-1+ T-cells and PD-1+ B-cells increased under hyponatremia conditions. Effector (CD45RA+CCR7-CD27-CD28-) CD8+ T cells, which represent the final stage of T-cell differentiation and have the lowest proliferative capacity, are increased in the state of hyponatremia. Expression of tumor necrosis factor-α (TNF-α) with pleiotropic effects was increased in T-cells (CD4+ and CD8+) in hyponatremia. Moreover, CD16+ myeloid dendritic cells (mDCs), which can produce higher levels of TNF-α compared with other DC subsets, were increased in the hyponatremic state.
Overall, it is observed that the hypoosmolar milieu formed in the cells in case of hyponatremia leads to exhaustion of T cells and progression of T cell differentiation to the terminal stage. TNF-α-mediated apoptosis may play a role in the clearance of damaged cells in the hypoosmolar milieu due to the increase in TNF-α-producing cells.