Cardiac surgery modulates leucocyte subsets and inflammatory mediators.

Area of Science:

• Immunology
• Cardiovascular Surgery
• Hematology

Background:

• Leukocytes and cytokines are crucial for immune responses and host defense.
• Coronary artery bypass grafting (CABG) triggers a systemic inflammatory response, potentially leading to adverse patient outcomes.
• Standard full blood counts (FBC) offer limited insight into specific leukocyte subsets.

Purpose of the Study:

• To investigate the impact of CABG on circulating leukocyte subsets and plasma cytokine levels.
• To explore the relationship between CABG-induced immunomodulation and patient outcomes, specifically atrial fibrillation (AF) and intensive care unit length of stay (ICU LOS).

Main Methods:

• Whole blood samples were collected from 75 CABG patients at five time-points: admission, intra-operative, ICU, day 3 (D3), and day 5 (D5).
• Absolute counts of monocytes, NK cells, B cells, T cell subsets, and dendritic cell (DC) subsets were measured using Trucount tubes.
• Plasma cytokine levels were quantified using cytometric bead array, and FBC data were used to calculate lymphocyte monocyte and neutrophil lymphocyte ratios.

Main Results:

• Monocyte counts increased, while T-cell counts decreased post-ICU admission compared to baseline.
• B-cell counts initially decreased during surgery, then rose from D3 onwards.
• Classical DC numbers decreased, and plasmacytoid DC numbers increased during CABG, alongside elevated IL-6, MCP-10, and IP-10 plasma levels.
• Modulation of DC and T-cell subsets correlated with AF and ICU LOS.

Conclusions:

• CABG significantly alters circulating leukocyte subsets and plasma cytokine profiles.
• Comprehensive analysis of leukocyte subsets and ratios offers valuable insights into cardiac immunobiology post-CABG.
• Detailed hematological assessment can serve as a clinical tool for guiding postoperative management and predicting patient outcomes.