Endotoxin-induced microclots in ulcerative colitis and Crohn's disease.

Radially oriented fibrin microclots were observed when blood from patients with active lesions of Crohn's disease and ulcerative colitis was kept in capillary tubes for 24 h. Addition of bacterial extract or endotoxins increased the fibrin formation. The phenomenon is not seen in healthy subjects or patients who have healed after colectomy. The data are consistent with our findings in patients with vasculitis and support the view that patients with Crohn's disease and ulcerative colitis have circulatory endotoxins.