Heat-shock protein 65 and atherosclerosis in patients on regular hemodialysis.

This article is also accessible online at: http://BioMedNet.com/karger Dear Sir, Atherosclerosis is one of the most significant yet unresolved problems in patients on regular hemodialysis (HD) with major impact on morbidity and mortality in patients with end-stage renal disease. A number of risk factors associated with the development of atherosclerosis in HD patients have been identified, such as hyperlipidemia, hypertension, diabetes, smoking and obesity [1]. There is growing evidence that atherosclerosis may – at least in part – result from autoimmune processes, in which the family of heat-shock proteins (HSP) may be involved [2]. HSPs are a family of about two dozen proteins which show highly homologous sequences between bacterial and mammalian species. They are induced during chronic inflammation and other forms of physiological stress. Experimental evidence has shown that expression of HSP 60 on endothelial cells triggers early inflammatory atherosclerotic changes [3]. Furthermore, immunisation of normocholesterolemic rabbits with a mycobacterial 65-kD HSP (mHSP 65) induced typical atherosclerotic lesions [2]. Crossreactivity of serum antibodies against mHSP 65 with the human 60kD homologue present in high levels in atherosclerotic lesions was demonstrated by immunoblotting and immunofluorescence techniques [4]. In a series of 27 human subjects HSP 60 could be detected on endothelium, smooth muscle cells and/or mononuclear cells of carotid and aortic specimens with atherosclerotic lesions. No expression of stress protein was detectable on control specimens with normal intima [5]. In the present series we studied antibody titers against mHSP 65 in patients on regular hemodialysis (HD) (table 1). In total, 77 patients were included in the study (27 females, 50 males; mean age 59 B 12 years). The major causes for end-stage renal disease were chronic glomerulonephritis, diabetic nephropathy and interstitial nephritis. Of the 77 patients 29 (6 females, 23 males; mean age 61 B 12 years) showed typical manifestations of vascular disease as defined by cardiac ischemia and/or peripheral vascular disease. All 29 patients had typical clinical symptoms and angiography was performed to confirm the diagnosis. The remaining 48 patients (21 females, 27 males; mean age 57 B 13 years) did not show symptoms of significant vascular disease. As a control, sera were obtained from healthy subjects (medical students and laboratory staff, n = 90, 48 females, 42 males, mean age 32 B 12 years). Purified recombinant (r)mHSP 65 has been kindly provided by Dr. Jan van Embden from the WHO IMMTUB/IMMLEP Bank. The microtiter plates were coated with mHSP 65 overnight at 4°C. After a washing step, the wells were blocked with non-fatty dry milk powder (Merck) in PBS and after washing incubated with diluted patient sera. After extensive washing the plates were incubated with peroxidase-conjugated rabbit antihuman IgG antiserum. The plates were washed again and developed by addition of substrate. The absorbance was measured in an ELISA reader at 405 nm. In each assay one positive serum was included as a posi-