Change in the acid protease activity in plasma of patients with disseminated intravascular coagulation.

Lysosomal protease was determined in the serum of patients with disseminated intravascular coagulation (DIC) to clarify whether the platelet count is an appropriate diagnostic index which allows the early initiation of treatment. The platelet count and the serum level of cathepsin D, a lysosomal protease, were determined in 60 patients diagnosed to have DIC. The cathepsin D activity could not be detected in the sera of healthy individuals with a platelet count of 100,000 or above, but was detectable in the serum of DIC patients with a platelet count of 100,000, and this activity increased as the platelet count decreased to 70,000 and 50,000, and was about 5 times higher at a platelet count of 30,000 than at 70,000. In DIC patients, the decrease in the platelet count was correlated with the increase in the serum lysosomal protease activity. The appearance of cathepsin D activity in the serum of DIC patients is considered to reflect the release of lysosomal enzyme activities from damaged organs, and the treatment for DIC must be initiated before the platelet count decrease below 100,000, and cathepsin D activity then appears in the serum. At a platelet count of 30,000 or less, DIC becomes established, and no therapeutic effects can be expected because of the associated multiple organ failure.