Humoral anti-proteasomal autoimmunity in dilated cardiomyopathy

Virus-induced chronic inflammation, autoimmune processes and impaired protein quality control may be involved in the pathogenesis of dilated cardiomyopathy (DCM). The ubiquitin–proteasome system is important in the modulation of inflammatory processes and the immune response. Proteasomes were identified as targets of a humoral autoimmune response in systemic inflammatory diseases, which provoked us to investigate anti-proteasomal immunity in DCM in detail: a total of 90 DCM patients with impaired left-ventricular function (LVEF ≤ 45%) were enrolled in this study. Autoimmune response to cardiac proteasomes was found to be enhanced in DCM patients, revealing the detection of predominantly α subunits of the 20S proteasome complex. Proteasome antibody (ProtAb) levels were found to be particularly enhanced at stages of advanced heart failure: moderately decreased LVEF and considerably increased NT-pro BNP levels were observed in DCM patients who tested positive for ProtAb ( P