SERUM IMMUNOGLOBULIN-G REACTIVE WITH ENDOTHELIAL-CELLS IN INFLAMMATORY BOWEL-DISEASE

Evidence of a humoral immune response to endothelium was sought in the sera of patients with inflammatory bowel disease. In an ELISA, IgG bi nding to human umbilical vein endothelial cells was found in 21% of Cr ohn's disease sera, 10% of ulcerative colitis sera, 6% of sera from pa tients with acute infective diarrhea, and 8% of normal control sera. T he increased prevalence in Crohn's disease sera was significant (P < 0 .05). IgG-endothelial cell binding was cell specific, was not Fc-media ted, and did not mediate complement-dependent cell lysis. It was not i ncreased by pretreatment of cells with interleukin-1 or tumor necrosis factor. Endothelial cell binding was retained by IgG F(ab')(2) fragme nts from one of three reactive Crohn's sera, but none of three nonreac tive sera. The low prevalence of this interaction, even in patients wi th immunohistochemically confirmed vasculitis, makes it unlikely that Crohn's disease is determined by a humoral autoimmune response to endo thelium.