Increased concentrations of inflammatory mediators in unstable angina: correlation with serum troponin T

OBJECTIVE: To measure plasma interferon gamma, monocyte chemotactic protein-1 (MCP-1), and interleukin 6 and to assess their correlation with cardiac troponin T in unstable angina.

DESIGN: Blood sampling in patients undergoing coronary arteriography for known or suspected ischaemic heart disease.

PATIENTS: 76 patients divided in three groups: 29 with unstable angina (group 1), 28 with stable angina (group 2), and 19 without ischaemic heart disease and with angiographically normal coronary arteries (group 3).

MAIN OUTCOME MEASURES: Plasma interleukin 6, interferon gamma, MCP-1, and troponin T in the three groups of patients.

RESULTS: Interleukin 6 was increased in group 1 (median 2.19 (range 0.53-50.84) pg/ml) compared with the control group (1.62 (0.79-3.98) pg/ml) (p < 0.005), whereas interferon gamma was higher in group 1 (range 0-5.51 pg/ml) than in the other two groups (range 0-0.74 pg/ml and 0-0.37 pg/ml; p < 0.005 and p < 0.001, respectively). Patients with unstable angina (group 1) and positive troponin T had higher concentrations of interferon gamma than those with negative troponin T (0-5.51 pg/ml v 0-0.60 pg/ml, p < 0.001). Plasma MCP-1 was also higher in group 1 (median 267 (range 6-8670) pg/ml) than in the other two groups (134 (19-890) pg/ml and 84.5 (5-325) pg/ml; p < 0.005 and p < 0.001, respectively), and among group 1 patients with a positive troponin T assay than in those with normal troponin T (531 (14.5-8670) pg/ml v 69 (6-3333) pg/ml; p < 0.01). There was no difference in plasma interleukin 6 in group 1 patients between those with and without raised troponin T.

CONCLUSIONS: The inflammatory cytokines interferon gamma and MCP-1 are increased in patients with unstable angina, particularly in those with raised concentrations of troponin T, suggesting that they are probably related to myocardial cell damage or to plaque rupture and thrombus formation.