Evaluation of klotho expression on peripheral blood lymphocytes among hemodialysis patients and its possible contribution to their immuno-compromised status.

Infection is the second most common cause of mortality among end-stage kidney disease (ESKD) patients. Uremic toxins are the main cause of impaired immune response among ESKD patients. Klotho gene, the anti-aging gene, encodes the transmembrane alpha klotho (αKL) protein which acts as an obligate coreceptor for fibroblast growth factor 23 (FGF23). Klotho protein may play a role in immune cell functions, particularly in anti-inflammatory response; however, its role is still incompletely understood. In the present study, we aimed to measure αKL protein expression on peripheral blood lymphocytes (PBLs) among hemodialysis (HD) patients, and we assumed that decreased αKL expression on PBLs may contribute to the impaired immunity among HD patients. This case-control study included 20 ESKD patients on regular hemodialysis for more than 3 months. Their ages ranged from 24 to 69 years. Patients with primary immunodeficiencies, those on systemic immunosuppressive drugs, those with ongoing infections or who had recently recovered from infections, and those with malignancies on active treatment were excluded. A control group of 20 normal subjects of comparable age and gender were also included. We compared αKL protein expression on PBLs by flow cytometry between both groups. Significant reductions in percentages of αKL protein expression on B lymphocytes (CD19), T lymphocytes (CD3), and natural killer cells (CD56) were observed among HD patients compared to controls. We also noticed a significant reduction in the percentages of natural killer cells among HD patients. The present study suggests that decreased αKL expression on PBLs may contribute to the immunocompromised status among HD patients, highlighting the importance of understanding the exact function of αKL protein on immune cells. This may offer a future diagnostic and therapeutic tool to improve the immune response among HD patients.