Anti-heat-shock protein 70 kDa antibodies in vascular patients

Introduction and aim of study: there is recent evidence that the immune system plays an essential role in the pathogenesis of atherosclerosis, with both cellular and humoral mechanisms being involved. Heat-shock proteins (HSPs) have been detected in atherosclerotic lesions, and antibodies to HSPs have also been found to be raised in patients with carotid stenoses. The aim of our study was to examine the level of anti-HSP70 antibodies in patients with other vascular diseases.

Materials and methods: a questionnaire was designed for the subjects in the study, with documentation of clinical details and ankle-brachial pressure index. Patients with concomitant infection, malignancy, hepatorenal failure, or recent surgery were excluded. Enzyme-linked immunosorbent assay (ELISA) was used to identify anti-HSP70 antibodies in the sera in different dilutions. Graphs of optical density (OD) vs. negative log dilution were plotted, the gradient of which was taken to be the estimated optical density for each subject (proportional to antibody level). Our groups consisted of controls (n =21, mean age 59.0+/-19.2), lower limb claudicants ( n =19, mean age 60.0+/-12.6), patients with lower-limb critical ischaemia ( n =22, mean age 68.5+/-10.07), and patients with abdominal aortic aneurysms ( n =20, mean age 69.9+/-6.2).

Results: we found no correlation between age and the estimated OD in our subjects (Spearman's correlation coefficient ( r )=0.123, one-tailed p value was 0.135). Patients with intermittent claudication, critical lower limb ischaemia, and aneurysms had higher estimated OD, and therefore higher anti-HSP70 antibody levels, than controls (Mann-Whitney test p =0.0127, 0.0037, 0.0008, respectively).

Conclusions: our data provide the first evidence of a correlation between anti-HSP70 antibodies and different types of vascular diseases, suggesting that HSP70 might be involved in the pathogenesis and propagation of atherosclerosis. Since the immune response to HSPs can be modulated, this opens up the possibility of new therapeutic approaches.