Elevated levels of interleukin-6 in unstable angina

Background Elevated plasma levels of C-reactive protein have been found in the majority of patients with unstable angina. The evidence of elevated levels of acute-phase proteins in unstable angina is in line with a growing body of evidence that suggests that inflammation plays a role in this syndrome and is an indirect sign of increased production of interleukin-6, which is the major determinant of acute-phase–protein production by the liver. However, in unstable angina, there is no direct proof of the role played by interleukin-6. Methods and Results We measured levels of interleukin-6 in 38 patients with unstable angina at the time of their admission to the coronary care unit and in 29 patients with stable angina. In the same groups of patients, we also measured C-reactive protein. Interleukin-6 (undetectable, ie, <3 pg/mL, in healthy volunteers) was detectable in 23 (61%) of 38 patients with unstable angina but in only 6 (21%) of 29 with stable angina (P<.01). Median interleukin-6 levels were 5.25 pg/m...