Immunoglobulin G Subclass Distribution of Anti-Endothelial Cell Antibodies (AECA) in Patients with Ulcerative Colitis or Crohn's Disease

Anti-endothelial cell antibodies have beendescribed in sera from patients with inflammatory boweldisease. The aim of this study was to determine, byELISA, the IgG subclass distribution of anti-endothelial cell antibodies, in patients with ulcerativecolitis (N = 28) or Crohn's disease (N = 82) as comparedwith blood donors (N = 95). Thirty-six percent ofulcerative colitis and 23% of Crohn's disease patients were positive for at least one of the IgGanti-endothelial cell subclasses. Interestingly, thepattern of IgG anti-endothelial cell subclass observedin the two inflammatory bowel diseases differs. InCrohn's disease, the IgG1 anti-endothelial cellantibody level was significantly increased (P < 0.05)while IgG2 and IgG4 anti-endothelial cell antibodylevels were decreased (P < 0.0001 and P < 0.01, respectively) as compared to ulcerative colitispatients. The immunoglobulin G3anti-endothelial cell antibody level was decreased inboth ulcerative colitis and Crohn's disease patients ascompared to healthy blood donors. No relationship wasdetected between disease activity of ulcerative colitisor Crohn's disease patients and anti-endothelial cellIgG subclasses. Finally, the disparity of IgGanti-endothelial cell subclass distribution in these twoinflammatory bowel diseases suggests that the ability toactivate effector mechanisms is not identical, andhence, deals with the concept of distinctivepathogenetic mechanisms in these two diseases.