title: Endotoxin-neutralizing capacity of serum from cardiac surgical patients.
abstract: OBJECTIVE
  To determine if endotoxin core antibody (EndoCAb) from the serum of cardiac surgical patients neutralizes endotoxin in an ex vivo biologic assay.
  
  
  METHODS
  Prospective blinded cohort study.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  Patients (n = 203) undergoing cardiac surgery.
  
  
  METHODS
  Sera were obtained from patients preoperatively.
  
  
  RESULTS
  EndoCAb levels were determined by enzyme-linked immunosorbent assay. Sera were incubated for 15 minutes at 37 degrees C with varying concentrations of endotoxin from a clinically relevant bacterium (Escherichia coli serotype O18), then tested for the presence of endotoxin activity using the validated Limulus amebocyte lysate assay. Median (interquartile range) IgM and IgG EndoCAb levels were 118 median units (range, 31 to 259 median units) and 208 median units (range, 108 to 401 medium units). Increasing levels of IgM EndoCAb were associated with increased neutralization of endotoxin (p < 0.0001). Increasing levels of IgG EndoCAb were associated with increased neutralization of endotoxin (p < 0.0001). An additive effect of IgM and IgG EndoCAb levels on endotoxin neutralization was observed without evidence of synergistic or plateau effects. EndoCAb levels did not completely predict serum neutralization capacity.
  
  
  CONCLUSIONS
  Anti-EndoCAbs of both classes (IgM and IgG) were able to neutralize lipopolysaccharide from a clinically relevant bacterium in an ex vivo model. Neither Igm nor IgG appeared to be more capable of neutralization in this model. These antibodies did not completely predict neutralization capacity; other endogenous factors in human serum must be capable of lipopolysaccharide neutralization.
authors.affiliation: Department of Anesthesiology, Columbia University College of Physicians and Surgeons, New York, NY 10032-3784, USA. eb413@columbia.edu
authors.forename: E
authors.initials: E
authors.lastname: Bennett-Guerrero
authors.forename: G R
authors.initials: GR
authors.lastname: Barclay
authors.forename: P L
authors.initials: PL
authors.lastname: Weng
authors.forename: C A
authors.initials: CA
authors.lastname: Bodian
authors.forename: D E
authors.initials: DE
authors.lastname: Feierman
authors.forename: F
authors.initials: F
authors.lastname: Vela-Cantos
authors.forename: M G
authors.initials: MG
authors.lastname: Mythen
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D006348:Cardiac Surgical Procedures; D004731:Endotoxins / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008033:Limulus Test; D008070:Lipopolysaccharides / Q000276:immunology; D009500:Neutralization Tests; D011446:Prospective Studies
chemical_list: D000907:Antibodies, Bacterial; D004731:Endotoxins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008070:Lipopolysaccharides