Profiles of antibodies to poly(ADP-ribose), left-handed Z-DNA, and other nuclear constituents in systemic lupus erythematosus and progressive systemic sclerosis.

A simple and sensitive method was developed for detection of antibodies to histones using a modification of the enzyme-linked immunosorbent assay (ELISA) for antibodies to nucleic acids. The antigens used for antibody assay were poly(ADP-ribose), left-handed Z-DNA, double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), and calf thymus histones. These five antigen-antibody systems were used to examine the antibodies in patients with systemic lupus erythematosus (SLE) and progressive systemic sclerosis (PSS). A positive correlation was found between the antibody titers in patients with PSS. However, weak correlation was found between the titers of antibodies to these nuclear antigens in the SLE patients, except for correlations between the titers of antibodies to left-handed Z-DNA and histones, and those to ssDNA and dsDNA. From these data, it is suggested that presentation of modified chromatin to immune systems is involved in antinuclear antibody formation in PSS patients, whereas spontaneous expansion of clones for antinuclear antibodies may occur in SLE patients under certain conditions.