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Complement activation and neutropenia occurring during cardiopulmonary bypass
The Journal of Thoracic and Cardiovascular Surgery
|March 1, 1981
Summary
Cardiopulmonary bypass (CPB) activates complement, causing neutropenia and altered neutrophil function. This suggests complement-mediated inflammation may contribute to CPB-related complications.
Area of Science:
- Immunology
- Cardiovascular Surgery
- Critical Care Medicine
Background:
- Extracorporeal circulation systems like hemodialysis can activate complement, leading to pulmonary leukostasis and neutropenia.
- Pulmonary dysfunction is a known complication associated with these extracorporeal procedures.
Purpose of the Study:
- To investigate whether similar complement activation and leukostasis phenomena occur during cardiopulmonary bypass (CPB).
- To assess the functional changes in neutrophils following CPB.
Main Methods:
- Studied 34 patients undergoing coronary artery bypass operations with CPB.
- Monitored neutrophil counts, complement levels (CH50, C3H50), and neutrophil function (adherence, chemotaxis, aggregation) during CPB.
- Analyzed plasma for complement conversion products (C3, C5a).
Main Results:
- Neutropenia occurred during CPB, followed by neutrophilia.
- Significant decreases in CH50 and C3H50 levels were observed.
- Neutrophils harvested late in bypass exhibited reduced adherence and impaired response to C5a.
- Complement activation was detectable at levels below C5a detection thresholds in plasma.
Conclusions:
- Neutropenia during CPB is likely caused by complement activation, even if C5a is not detectable.
- Complement-stimulated neutrophils may play a role in CPB-associated tissue injury.
- Further research into complement-stimulated neutrophils is warranted to understand CPB complications.