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DOI: 10.1055/s-0038-1628349
The Expression of Pattern-Recognition Receptors Is Diminished after Paediatric Cardiopulmonary Bypass and Increased 48 Hours Later
Publication History
Publication Date:
22 January 2018 (online)
Objectives: Immune dysregulation and infection frequently complicates the recovery process after cardiac surgery and is a major challenge for pediatric intensive care medicine. Pattern-Recognition Receptors (PRR), especially Toll-Like Receptors (TLR), play a key role in the neutrophil and monocyte mediated innate immune response. This study aims at providing a deeper understanding of the underlying mechanisms to identify new prevention strategies and therapy approaches. Therefore, changes and clinical interrelations of TLR-2, TLR-4, Dectin-1 and other receptors are described.
Methods: The study included 21 infants younger than two years of age undergoing planned surgery for acyanotic heart defects with Cardiopulmonary Bypass (CPB). Fourteen blood samples were collected from each patient at specific points in time before, during and up to two days following surgery. The leucocyte surface expression of CD14, CD16, CD64, TLR-2, TLR-4 and Dectin-1 was determined by flow cytometry.
Results: Immediately after CPB the neutrophil and monocyte expression of TLR-2 (p < 0.0001) and Dectin-1 (p < 0.0001) was substantially reduced, as well as neutrophil TLR-4 (p = 0.0124). Whereas neutrophil CD16 (p < 0.0001) and monocytic CD14 (p < 0.0001) remained below preoperative levels even two days after surgery, monocyte TLR-2 (p = 0.0047) and TLR-4 (p = 0.0496) and also neutrophil TLR-2 (p < 0.0001) clearly exceeded the initial expressions.
Higher surface densities of neutrophil CD64 (p = 0.0453), TLR-2 (p = 0.0022) and Dectin-1 (p = 0.0007) 48 hours after CPB correlated with prolonged length of stay in the intensive care unit.
Conclusion: The study yielded not only the major influence of cardiac surgery on the early immune system, but also interrelations between recovery time and late immune response. Future studies should further clarify the underlying causalities that may potentially offer new points of therapeutic approach.