20.500.12556/DiRROS-29699 Impaired booster-induced SARS-CoV-2 antibody responses in rituximab-treated B-cell lymphoma patients despite peripheral B-Cell Recovery Rituximab-treated patients with B-cell lymphoma exhibit profound B-cell depletion and impaired vaccine-induced antibody responses. However, it remains uncertain whether recovery of peripheral B-cell counts after rituximab is sufficient to restore effective humoral immunity following booster vaccination. Patients and methods In this prospective, single-center observational study at the Institute of Oncology Ljubljana, adult B-cell lymphoma patients treated with or previously exposed to rituximab received the Comirnaty® mRNA COVID-19 vaccine. Antibody responses to the SARS-CoV-2 spike and nucleoprotein were measured at baseline, 14 days after the second dose, and at 3, 6, 9, and 12 months. A third dose was administered at 6 months. T-cell responses (IFN-γ release) were assessed in patients before and after the primary series and booster dose. Lymphocyte subsets were analysed pre-vaccination. Adverse events and nutritional status were monitored. Results Patients undergoing anti-CD20 therapy showed absent antibody responses. Longer intervals since rituximab correlated with peripheral B-cell repopulation. However, even after reaching normal B-cell counts, patients’ antibody responses after revaccination remained significantly lower than in controls. Conclusions Rituximab is associated with impaired vaccine-induced antibody responses. Despite recovery of peripheral B-cell counts, patients with B-cell lymphoma show reduced humoral responses compared with healthy individuals following booster COVID-19 vaccination. lymphoma B-cell rituximab COVID-19 vaccines limfom B-celični limfom rituksimab cepljenje proti covid-19 true false true Association of Radiology and Oncology Ljubljana Angleški jezik Slovenski jezik by Authors Neznano 2026-06-03 11:59:43 2026-06-03 11:59:43 2026-06-04 04:04:40 0000-00-00 00:00:00 2026 0 Ljubljana 0 str. 76-85 no. 1 Vol. 60 2026 0000-00-00 Zaloznikova Objavljeno apc 2026-02-16 2026-02-24 2026-03-24 616-006 1318-2099 276354563 RAZ_Jurca_Tomaz_2026.pdf RAZ_Jurca_Tomaz_2026.pdf 1 9F46EB0981FC1713704494301FD8281A 84252d043e84ee88225f6bfc703c59c6a52c0589c55cb6521796c9b501bc7372 fa7fb7d7-5f35-11f1-9215-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=44613 Onkološki inštitut Ljubljana 0 0 0