Autoimmune response to heat shock protein 60 in haemodialysis patients

Abstract

Dear Sir,We read with great interest the paper by Gruden et al. [1] recently published in Journal of Internal Medicine. The authors reported a significant inverse correlation between diabetic micro- and macroangiopathy and serum levels of anti-Heat Shock Protein 70 (HSP70) antibodies in a large cohort of type 1 diabetic patients. HSP70 levels resulted higher in healthy subjects compared with diabetic patients, while no significant difference was found in anti-HPS60 levels between patients and controls. In a longitudinal study, we investigated whether anti-HSP60 antibodies are associated with cardiovascular risk in adult patients on haemodialysis (HD). We evaluated anti-HSP60 serum levels in 33 nondiabetic patients (66.5 ± 10.4 years, m/f: 17/16) on regular HD. Then, we correlated the titer of the antibodies to cardiovascular risk factors, inflammation and incidence of cardiovascular events, during a 24-month follow-up. Cardiovascular risk factors considered were: smoking habit, diabetes, systolic blood pressure and serum cholesterol. Inflammation was assessed by high sensitivity C-Reactive Protein (hs-CRP) serum levels. Thirty healthy sex-age matched subjects (63.3 ± 7.7 years, m/f: 15/15) were the controls. Anti-HSP60 serum levels were measured by ELISA that detected IgG, IgA and IgM isotypes (Stressgen Biotechnologies Corporation,Victoria, BC, Canada). Anti-HSP60 were present in all analysed subjects; there was no significant difference in antibody levels between patients and controls (41.84 ± 34.78 vs. 38.47 ± 11.34 μg mL−1, respectively). Furthermore, anti-HSP60 did not correlate neither to hs-CRP serum levels nor to cardiovascular risk factors and incidence of cardiovascular events. Many studies have been focussed on the pathogenic or predictive role of anti-HSP60 antibodies in patients with ischaemic heart disease, with contrasting results [2–4]. We found no predictive role of anti-HSP60 in adult patients on regular HD, i.e. a population with a cardiovascular risk 20 to 30 times higher than in general population [5]. Our finding fits with the report of Gruden et al. in diabetic patients and add further doubt about a relevant pathogenic role of an autoimmune response to HSP60 in atherosclerosis. All authors state no conflict of interest.