Immune Perturbations After Cardiopulmonary Bypass: A Randomized Trial of Cytokine Adsorption

All articles of this category (opens in new window) Background: Cardiopulmonary bypass (CPB) induces profound immune alterations, including lymphopenia and neutrophilia. Hemoadsorption has been proposed as a strategy to mitigate these inflammatory responses; however, its impact on immune cell dynamics remains insufficiently defined. Methods: In a randomized study, 50 patients scheduled for elective cardiac surgery with CPB were allocated either to a group receiving intraoperative hemoadsorption (Cytosorb-Group, n = 25) or to a control group treated with the standard procedure (Control-Group, n = 25). Blood was collected at baseline (T0), after CPB (T1), 8 hours post-CPB (T2), and 24 hours post-CPB (T3). Leukocyte differentials and flow cytometry were performed. Analyses included within- and between-group comparisons and trajectory modeling. Results: Both groups displayed the characteristic postoperative immune shift. In the pooled cohort ( n = 50), neutrophils increased from 60% [95% CI: 57–63] at baseline to 76% [73–79] at T2 (Δ + 16%, p < 0.001), while lymphocytes declined from 28% [25–31] to 13% [11–15] (Δ–15%, p < 0.001). Monocyte subsets redistributed transiently: classical monocytes fell from 83% [81–85] to 76% [73–79], intermediates rose from 6% [5–7] to 8% [7–9], and nonclassicals dropped from 11% [10–12] to 7% [6–8] (all p < 0.05). Between-group contrasts revealed only isolated differences, such as lower nonclassicals in the Cytosorb-Group at T2 (5.3% vs. 6.6%, adj. p = 0.04). Mixed-effects models confirmed no significant group × time interaction for neutrophils, lymphocytes, or monocyte subsets (all adj. p > 0.1). Conclusion: CPB induces profound but transient immune perturbations, most evident 8 hours postoperatively. Hemoadsorption was associated with minor differences in selected subsets but did not alter overall immune trajectories. Larger trials are required to determine whether such immunological effects translate into clinical benefit. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany