Complement activation in plasma before and after infliximab treatment in Crohn disease.
BACKGROUND
Crohn disease is characterized by up-regulated intestinal inflammation mainly caused by increased tumour necrosis factor alpha (TNF-alpha) levels. However, the complement system (C) may also have a role in maintaining inflammation.


METHODS
Plasma from 26 patients with Crohn disease complicated by fistulizing ano-rectal disease was collected before and after three Infliximab infusions (5 mg kg(-1)).


RESULTS
Before treatment, the C3-activation capacities (C3-AC) in plasma from patients with Crohn disease were comparable with values obtained from healthy controls. The classical C pathway-mediated C3-AC, mannan-binding lectin C4-AC, leucocyte count, C-reactive protein concentration and Crohn Disease Activity Index decreased significantly 8 weeks after the first infusion of Infliximab (P < 0.04, Wilcoxon test).


CONCLUSIONS
Before treatment, all three C pathways were within the normal range in plasma from patients with Crohn disease; the decrease observed in the classical pathway-mediated C3-AC after treatment with Infliximab reflects a general down-regulation in immune activation.
Zimmermann-Nielsen
E
E
Dept. of Surgery K, Hospital of Funen, Svendborg Sygehus, Svendborg, Denmark. erzn.shf-post1@fyns-amt.dk
Agnholt
J
J
Thorlacius-Ussing
O
O
Dahlerup
J F
JF
Baatrup
G
G
D000293:Adolescent; D000328:Adult; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D002097:C-Reactive Protein / Q000032:analysis; D003167:Complement Activation / Q000276:immunology*; D003176:Complement C3 / Q000276:immunology; D003181:Complement C4 / Q000276:immunology; D003171:Complement Pathway, Classical; D003424:Crohn Disease / Q000188:drug therapy* / Q000276:immunology*; D015536:Down-Regulation; D005260:Female; D005765:Gastrointestinal Agents / Q000627:therapeutic use*; D006801:Humans; D000069285:Infliximab; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged
D000911:Antibodies, Monoclonal; D003176:Complement C3; D003181:Complement C4; D005765:Gastrointestinal Agents; D002097:C-Reactive Protein; D000069285:Infliximab