Influenza Vaccine Immunogenicity in Hemodialysis Patients

Patients with End-Stage Renal Disease on hemodialysis (HD) are at high risk for severe influen-za, and their underlying immune dysfunction may limit the magnitude of vaccine-induced pro-tection. This observational study evaluated the immune response in 93 hemodialysis patients vaccinated with the seasonal inactivated influenza vaccine (IIV) across the 2019-2020 (n=22) and 2023-2024 (n=71) seasons. Immune response was comprehensively assessed by measuring hemagglutina-tion inhibition (HAI) and neutralizing antibody titers and by analyzing the frequencies of key immune cells, including plasmablasts, T-follicular helper cells (Tfh), and effector memory T cells (Tem). The results of observation in 2019-2020 showed that the antibody response in HD patients was comparable to that of healthy volunteers, including both younger (18-60) and older (over 60) age groups. By day 7, there was a pronounced increase in activated Tfh1 cells, a corresponding surge in plasmablasts, and a rise in antigen-specific B-cells. A T-cell response followed, mediated by IFNγ-producing and polyfunctional CD4+ effector memory T cells. Subsequent vaccination in 2023-2024 season determined a higher baseline level of the antibody response but did not affect its further dynamics in case of A/H1N1pdm, A/H3N2, B/Yamagata virus antigens. The response to B/Victoria was higher in the revaccinated group throughout the entire observation period. Our findings confirm that standard-dose IIV vaccination is beneficial for HD patients, inducing a robust and compliant humoral and T-cell immune response that is not inferior to that of the general population.