Antinuclear antibody- and extractable nuclear antigen-related diseases

In 1948, the observation of the LE cell phenomenon in a patient with systemic lupus erythematosus (SLE) began the discovery of a broad variety of autoantibodies directed to nuclear antigens called antinuclear antibodies (ANA). Nowadays, different ANA serve as important diagnostic parameters for differentiating most of the connective tissue diseases, such as SLE, neonatal lupus syndromes, Sjögren's syndrome, scleroderma, autoimmune myositis, mixed connective tissue disease and other overlaps. This overview summarizes the history of ANA and their detection methods, in part to introduce the subsequent papers dealing with special topics of ANA-related diseases in this issue. Furthermore, the pathogenic role of these autoantibodies in targeting non-organ-specific intracellular antigens as a functional important constituent of a subcellular particle or multimolecular complex is addressed. Notably, some of these autoantibodies have functioned as significant tools for cell biologists to elucidate the subcellular structures and functions of these autoantigens. In the future, we can expect further advances to answer such important questions as why these antigens are targets of autoantibodies, what is their pathogenic impact and what are the triggers of autoimmunity?