Abstract:
<p align="justify"> Fibrinogen (FB), an acute-phase protein, is recognized as an independent risk factor in the plasma of patients with coronary heart disease (CHD). The plasma FB level is also significantly increased in inflammation and neoplasm. We performed an in vitro study showing that the chemiluminescence (CL) emission produced by zymosan-activated polymorphonuclear leukocytes (PMNL) was directly related to the concentration of FB, fibrinopeptide A, or FB-degradation products(FDP). Fibrin inhibited CL emission. We also found that the in vivo plasma levels of FB or FDP were significantly higher in the plasma of 1OO cardiac catheterized patients with CHD than in the plasma of the age and sex-matched controls. In 85% of the patients with CHD, both the plasma FB and the CL emission were significantly increased. In the other 15%, the plasma FDP level was higher than the FB level, however, the CL level was still higher than in the age and sex-matched controls. Activated PMNL may increase the plasma level of FDP as a consequence of enhanced enzyme-dependent degradation of FB. Our results indicate that the role of FB and independent risk factor in CHD depends on the level of activated polymorphonuclear leukocytes in the plasma </p>