Recently it has been shown that tissue factor (TF), an important trigger for initiating blood coagulation, is present in the circulating plasma. In order to assess the clinical implications of TF in plasma, plasma concentration of TF was quantitated in 65 patients with disseminated intravascular coagulation (DIC). The mean concentration of plasma TF was elevated in patients with DIC at presentation as compared with healthy subjects (446 +/- SD 536 pg/ml vs. 138 +/- 51 pg/ml, P < 0.001). Abnormally high levels were found only in 46.2% of the patients, predominantly in patients with non-hematological solid tumors and acute leukemia. Plasma TF did not correlate with hemostatic markers of DIC such as thrombin-antithrombin III complex, prothrombin fragment 1 + 2, plasma-alpha 2-plasmin inhibitor complex, FDP, D-dimer, or fibrinogen. Serial determinations of plasma TF demonstrated that plasma TF changes roughly in parallel with the course of DIC in most patients with elevated TF at presentation of DIC. These findings suggest that plasma TF is potentially valuable for monitoring the progress of DIC in a limited population of patients.

A 28-year-old Japanese woman with suspected essential thrombocythemia (ET) had marked thrombocytosis, mild leukocytosis with normal neutrophil alkaline phosphatase activity, and no anemia. She was monitored without being given any medication. Eleven years later, complete blood counts showed no remarkable changes but some non-lobulated mononuclear megakaryocytes were found in the bone marrow. Cytogenetic analysis revealed deletion of the long arm of chromosome 5 (5q-). Subsequently, hemoglobin and platelet counts decreased gradually, splenomegaly appeared and progressed, after which myelofibrosis developed. Acute leukemia developed 16 years after the first documentation of thrombocytosis. 5q- syndrome is known to be a myelodysplastic syndrome (MDS) with unique clinical features and cases with this syndrome presenting with thrombocytosis of more than 1,000 x 10(9)/L but without anemia are rare. Furthermore, it is noteworthy that in this patient transition to acute leukemia occurred following development of myelofibrosis and marked splenomegaly, which are generally observed in blastic crises resulting from chronic myeloproliferative disorders (CMPD). The patient showed features indicative of CMPD rather than of MDS in spite of presenting with 5q- chromosomal abnormality. This case supports the concept of "mixed myelodysplastic and myeloproliferative syndromes" and suggests the possibility of the appearance of CMPD-like manifestations in 5q- syndrome.