Monocyte activation after burns and endotoxemia.
We describe the settings in which monocytes (M) are activated, as monokines may mediate organ dysfunction occurring after surgery and sepsis. To monitor M activation, we measured the relative number of M cell surface receptors for C3b and iC3b by indirect immunofluorescence. M exposed to increasing concentrations of endotoxic lipopolysaccharide (LPS) expressed increased mean cell surface C3b receptor-dependent fluorescence (35 buffer alone vs 354 LPS at 1000 ng/ml) and iC3b receptor-dependent fluorescence (78 vs 404). To determine whether this M activation could be reproduced by endotoxemia, normal volunteers were randomly administered saline or a single dose of LPS (20 u/kg). We found increased M cell surface C3b receptors 4 hr after LPS (341 LPS (n = 22) vs 168 saline (n = 20)) which returned to control levels at 24 hr. A similar transient increase was seen at 4 hr with M cell surface iC3b receptors (304 LPS (n = 23) vs 104 saline (n = 20)). To determine whether this could be used clinically, seven patients with burns (10-70% body surface area) were serially sampled up to 50 days. Each patient demonstrated elevations of M cell surface C3b and iC3b receptors, which gradually decreased over many weeks. For the group as whole, mean M cell surface C3b receptor-dependent fluorescence was 287, Days 0-5 postburn (vs 132 in 147 normals); 315, Days 6-9; 217, Days 10-13; 237, Days 14-19; and 185, Days 20+.(ABSTRACT TRUNCATED AT 250 WORDS)
Moore
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FD
Department of Surgery, Brigham and Women's Hospital, Boston, Massachusetts.
Davis
C F
CF
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002056:Burns / Q000276:immunology*; D004731:Endotoxins / Q000097:blood* / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D011951:Receptors, Complement / Q000378:metabolism
D004731:Endotoxins; D008070:Lipopolysaccharides; D011951:Receptors, Complement