Early atherosclerosis and autoantibodies to heat-shock proteins and oxidized LDL in systemic sclerosis

Autoimmune diseases are characterized by enhanced atherosclerosis. Humoral immune responses to mycobacterial HSP-65, human HSP-60, and to oxLDL have been established in a number of human autoimmune diseases and are considered to be associated with atherosclerosis. The aim of this study was to evaluate carotid artery intima-media thickness (IMT) in patients having systemic sclerosis (SSc) and to find out whether early atherosclerosis is associated with these autoantibodies. Forty-four patients having SSc underwent clinical evaluation and carotid artery IMT measurement. Several autoantibodies were tested among patients and a control group. The antibodies against human HSP-60 were measured by antihuman (IgG/IgM) HSP-60 ELISA kit. IgGs and IgMs antimycobacterial HSP-65 were determined using an ELISA with mycobacterial recombinant HSP-65 antigens. Similarly, anti-oxLDL antibodies were measured by an ELISA kit. Abnormal IMT levels were significantly more common in SSc patients compared with control subjects. Age was found as the sole most significant clinical parameter associated with carotid artery IMT in SSc. Disease duration, type of SSc, lung function tests, and cardiovascular risk factors were not associated with IMT in these patients. Levels of HSP-60, HSP-65, and oxLDL autoantibodies were similar among patients compared with controls, and in patients having "positive" IgM anti-HSP-65, higher IMT values were found. Abnormal carotid IMT is more prevalent in SSc than in normal subjects. Age rather than other clinical parameters is associated with early atherosclerotic changes in SSc. Autoantibodies to oxLDL, HSP-60, and HSP-65 are not elevated in SSc and there is only a borderline association with carotid artery IMT.