Activation of neutrophils and monocytes by a leukocyte-depleting filter used throughout cardiopulmonary bypass

J Thorac Cardiovasc Surg. 2005 Apr;129(4):851-9. doi: 10.1016/j.jtcvs.2004.07.061.


Objective: Cardiopulmonary bypass elicits systemic inflammation. Depletion of circulating leukocytes might alleviate inflammatory response. We studied the effects of a leukocyte-depleting filter on phagocyte activation during cardiopulmonary bypass.

Methods: Fifty patients undergoing coronary artery bypass grafting were randomly allocated into an arterial line leukocyte filter group (n = 25) with a Pall LeukoGuard 6 leukocyte-depleting filter (LG6; Pall Biomedical, Portsmouth, United Kingdom) and a control group without any filter (n = 25). Blood sampling took place from arterial line at predetermined time points. In the filter group, the sample was taken immediately before the filter; to evaluate activation at the site, an additional sample was taken immediately after the filter. CD11b/CD18 and L-selectin expressions and basal production of hydrogen peroxide were determined with whole-blood flow cytometry, and plasma lactoferrin level was determined with enzyme-linked immunosorbent assay.

Results: Neutrophil CD11b expression was higher in the filter group than in the control group (P < .001). Likewise, monocyte CD11b expression, neutrophil hydrogen peroxide production, and lactoferrin plasma levels were all significantly higher, whereas neutrophil and monocyte counts and neutrophil L-selectin expression were all significantly lower in the filter group (all P < .001). At 5 minutes of CPB, CD11b expression increased across the filter on neutrophils (median difference 197 relative fluorescence units, range 45-431 relative fluorescence units, P < .001) and monocytes (median difference 26 relative fluorescence units, range -68-111 relative fluorescence units, P < .001).

Conclusion: The LG6 arterial line leukocyte filter is ineffective in its principal task of diminishing phagocyte activation during cardiopulmonary bypass.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • CD11b Antigen / blood
  • Cardiopulmonary Bypass*
  • Female
  • Humans
  • Hydrogen Peroxide / blood
  • L-Selectin / blood
  • Lactoferrin / blood
  • Leukocyte Count
  • Leukocyte Reduction Procedures / instrumentation*
  • Leukocyte Reduction Procedures / methods
  • Macrophage-1 Antigen / blood
  • Male
  • Middle Aged
  • Monocytes / physiology*
  • Neutrophil Activation / physiology*
  • Neutrophils / physiology*
  • Respiratory Burst / physiology
  • Time Factors


  • CD11b Antigen
  • Macrophage-1 Antigen
  • L-Selectin
  • Hydrogen Peroxide
  • Lactoferrin