Activation of the lectin pathway of complement by cardiopulmonary bypass contributes to the development of systemic inflammatory response syndrome after paediatric cardiac surgery

Clin Exp Immunol. 2016 May;184(2):257-63. doi: 10.1111/cei.12763. Epub 2016 Feb 8.


The systemic inflammatory response is a challenge in the management of paediatric patients undergoing cardiac surgery. Although multi-factorial, a contribution by the lectin pathway of complement activation has been postulated. We therefore investigated the changes in serum levels of mannose binding lectin (MBL) and activities of MBL-MBL-associated serine protease (MASP)-1 and MBL-MASP-2 complexes immediately before and during surgery, throughout the first postoperative day and at discharge from the hospital. These changes were analysed in relation to postoperative complications. Blood samples were obtained from 185 children with congenital heart disease undergoing surgical correction with the use of cardiopulmonary bypass: preoperatively (MBL-1), 15 min after initiation of cardiopulmonary bypass (CPB) (MBL-E), 30 min (MBL-2), 4 h (MBL-3), 12 h (MBL-4) and 24 h (MBL-5) post-CPB and at discharge from hospital (MBL-K). Alterations in serum MBL levels were calculated as a ratio of its serum level at subsequent time-points (MBL-2, -3, -4, -5) to the preoperative (MBL-1) value. Decreases in MBL and MBL-MASP complexes were observed in all samples, correlating with a decrease in C4 and increase in C4a, confirming activation of the lectin pathway. Changes in MBL levels between children with an uncomplicated postoperative course and those suffering from infection or low cardiac output syndrome did not differ significantly, but significant differences were observed between the SIRS and non-SIRS groups. Paediatric cardiac surgery with the use of cardiopulmonary bypass activates the complement system via the lectin pathway and the latter contributes to the development of the post-bypass systemic inflammatory response.

Keywords: cardiopulmonary bypass; complement; immunology; inflammation systemic; paediatric.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Cardiac Surgical Procedures / adverse effects*
  • Cardiopulmonary Bypass / adverse effects*
  • Child
  • Child, Preschool
  • Complement Activation / immunology
  • Complement C4a / metabolism
  • Complement C5a / metabolism
  • Complement Pathway, Mannose-Binding Lectin / immunology*
  • Female
  • Humans
  • Infant
  • Male
  • Mannose-Binding Lectin / blood*
  • Mannose-Binding Lectin / metabolism
  • Mannose-Binding Protein-Associated Serine Proteases / metabolism
  • Postoperative Complications / immunology*
  • Systemic Inflammatory Response Syndrome / immunology*


  • Mannose-Binding Lectin
  • Complement C4a
  • Complement C5a
  • MASP1 protein, human
  • MASP2 protein, human
  • Mannose-Binding Protein-Associated Serine Proteases