[Effect of complement 4 genetic polymorphism on complement activation during cardiopulmonary bypass in open heart surgery among children].
OBJECTIVE
To evaluate the relation between complement 4 genetic polymorphism and complement activation during extracorporeal circulation in open heart surgery among children.


METHODS
One hundred and fifty-six children to undergo open heart surgery with cardiopulmonary bypass in Wuhan and surrounding areas were investigated. Blood samples were obtained before the operation to analyze the C4 phenotypes by crossed immunoelectrophoresis. Before the initiation of CPB, at the end of CPB, and 10 minutes after protamine infusion, arterial blood samples were drawn to test the C4a and C3a with radioimmunoassay and lung compliance was recorded.


RESULTS
The frequencies of C4 genetic phenotypes AABB, AOBB, OOBB, AABO, and AAOO were 51.28%, 17.95%, 4.49%, and 19.80% respectively among the investigated children. At the end of CPB, The C4a levels remained almost the same, and C3a levels increased significantly. Ten minutes after the protamine infusion, significant increase was seen in the levels of both C4a and C3a, especially in the OOBB phenotype group followed by AOBB phenotype group. The lung compliance began to decrease by the end of CPB, most significantly in the OOBB phenotype group, followed by the AOBB group, along with the increase of C4a level.


CONCLUSIONS
The complement system is activated by the alternative pathway during CPB and by the classic way during the formation of protamine-heparin complexes. The complement system is activated and the lung function is damaged the most seriously during CPB among the persons with OOBB phenotype. The frequency of OOBB phenotype is higher among Chinese than among Caucasians.
Zhang
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S
Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Li
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Q
Yao
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S
D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D002648:Child; D002675:Child, Preschool; D003167:Complement Activation; D015926:Complement C3a / Q000032:analysis; D003181:Complement C4 / Q000235:genetics*; D015934:Complement C4a / Q000032:analysis; D005260:Female; D006493:Heparin / Q000378:metabolism; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011479:Protamines / Q000008:administration & dosage / Q000494:pharmacology
D003181:Complement C4; D011479:Protamines; D015926:Complement C3a; D015934:Complement C4a; D006493:Heparin