Serum levels of anti heat shock protein 70 antibodies in patients with stable and unstable angina pectoris

BACKGROUND: The heat shock protein (HSP) family comprises approximately 24 proteins displaying a high degree of sequence homology between different species. The induction of self-HSP immune reactivity is thought to be involved in the pathogenesis of several diseases. Antibodies to HSP60/65 have been demonstrated in the sera of patients with coronary artery disease. Moreover, the target antigens of the antibodies HSP60 and HSP70 are both expressed in smooth muscle cells and macrophages within atherosclerotic lesions. In this retrospective, case control study, we investigated whether patients with established atherosclerosis, with either stable or unstable angina have high levels of antibodies to HSP70. METHODS AND RESULTS: Patients with stable angina (n = 40) were from the outpatient clinic whereas patients with unstable angina (n = 91) were recruited upon admission and prior to performance of coronary angiography. Control patients (n = 18) were healthy subjects with no evidence of coronary artery disease. Serum levels of anti-HSP70 antibodies were assayed by ELISA. Patients with stable and unstable angina exhibited lower serum levels of antibodies to HSP70 (0.202+/-0.113 and 0.201+/-0.115, respectively) in comparison to control subjects (0.364+/-0.199, P = 0.0001 for both comparisons). Serum levels of antibodies to HSP70 did not differ significantly between patients with stable and unstable angina. No differences in serum levels of antibodies to HSP70 were evident between baseline and follow up in the patients with unstable angina. CONCLUSIONS: Patients with coronary atherosclerosis possess lower levels of anti-HSP70 antibody levels. Further research is required to explore whether higher levels of anti-HSP70 antibodies have a predictive value in coronary atherosclerosis.