The plasma level of soluble E-selectin (sE) reflects the activation of endothelial cells induced by cytokines such as tumor necrosis factor-alpha and interleukin-1 in vitro. These cytokines are important in the development of coagulation abnormalities in patients with sepsis. We compared the plasma levels of sE in patients with infections suspected of having disseminated intravascular coagulation (DIC) (n = 33) and in patients with underlying disorders other than infections, including solid tumors (n = 28), obstetric disorders (n = 13), hematologic malignancies (n = 13), and liver disease (n = 9), to clarify the involvement of cytokines in the development of coagulation abnormalities in patients with sepsis. Plasma levels of sE in patients with infection were significantly higher than in patients with the other underlying disorders. The plasma level of sE was also significantly higher in patients with infection with DIC (114.6 +/- 77.9 ng/ml, n = 21) than in patients with infection without DIC (54.5 +/- 53.1 ng/ml, n = 12, P < 0.02). There was no significant difference in sE level between patients with the other underlying disorders with and without DIC. The plasma level of sE was significantly correlated with the serum level of FDP(E) in patients with infection. The plasma level of sE was significantly higher in patients with infection with organ failure compared to patients without organ failure. There was no significant difference between patients with the other underlying disorders with and without organ failure. Plasma levels of tumor necrosis factor-alpha and interleukin-6 were detected in only 12.1% and 20.0% of patients with infections, respectively. These observations strongly suggest that plasma levels of sE reflect the activation of endothelial cells induced by cytokines, which may lead to DIC and organ failure in the presence of sepsis. Furthermore, determination of plasma level of sE may be useful for detecting the endothelial activation induced by cytokines in the pathologic conditions of sepsis, even when plasma levels of cytokines cannot be detected.