OBJECTIVE To measure plasma interferon γ, 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 γ, 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 γ 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 γ than those with negative troponin T (0–5.51 pg/mlv 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/mlv 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 γ 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.