Anti-human Hsp60 Autoantibodies in Autoimmune and Inflammatory Rheumatic Diseases

Abstract

Autoantibodies against human heat shock protein 60 (Hsp60) have been implicated in the pathogenesis of autoimmune and inflammatory rheumatic diseases (AIRDs), including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis, Sjogren’s syndrome and various idiopathic vasculitides. Anti-human Hsp60 autoantibodies can be detected in the sera of patients with AIRDs in various frequencies and levels; therefore, their diagnostic, clinical and pathogenic importance remains enigmatic. Regarding their clinical significance, several studies have implicated them in AIRDs with vascular manifestations, including SLE and primary vasculitides. For other diseases, however, clinical associations have not been comprehensively investigated. Their pathogenetic role is also questionable, although several studies have suggested an apoptotic capacity of anti-Hsp60 autoantibodies on osteoblasts and endothelial cells, linking them with joint inflammation and bone erosion in RA and vascular inflammation in SLE and vasculitides, respectively. In addition, molecular mimicry based on amino acid similarities between human Hsp60 and bacterial Hsp60 or other bacterial antigens has been implicated in the production of cross-reactive autoantibodies in AIRDS, connecting infection with autoimmunity and autoimmune disease. In search of the connection between anti-human Hsp60 autoantibodies and AIRDS, the current chapter reviews research advances in the field and discusses prospective investigations.