Background-Activation of T cells and macrophages has been associated with u
nstable angina (UA), but whether this reflects specific immune responses re
mains unclear.
Methods and Results-We analyzed the repertoire and the length of complement
arity -determining region 3 of the T cell receptor (TCR) beta-chain variabl
e (BV) gene segments of activated lymphocytes in 23 patients with UA, 13 pa
tients with chronic stable angina (CSA), and 6 normal control subjects. We
also tested the proliferation of systemic T cells in response to autologous
coronary plaque proteins, oxidized LDL, and Chlamydia pneumoniae as candid
ate antigens, in vitro. The activated T cell-TCRBV repertoire was perturbed
in 13 (57%) of 23 UA patients versus 3 (23%) of 13 CSA patients (P=0.016)
and was restricted to 6 (28%) of 21 expanded TCRBV families; all were signi
ficantly higher in UA than in CSA patients. At least one monotypic or oligo
typic activated TCRBV population was found in 15 (65%) of 23 UA patients an
d in 3 (23%) of 13 CSA patients (P<0.001). Finally, T cells from UA patient
s, but not from CSA patients or normal control subjects, proliferated in re
sponse to autologous proteins from coronary culprit lesions and/or to oxidi
zed LDL.
Conclusions-Our findings suggest that the T-cell response observed in UA pa
tients is antigen-driven and directed to antigens contained in the culprit
coronary atherosclerotic plaques.