We tested sera of patients with various autoimmune rheumatic diseases for the presence of antibodies against sulphatide (an acidic glycosphingolipid), identified as a target antigen for antibodies against the liver cell membrane. Thirty-five percent (7/20) of patients with lupus in the active stage possessed anti-sulphatide antibodies, whereas 10% (2/20) of those in the inactive stage and 20% (4/20) of those in the stationary stage possessed such antibodies. Moreover, 10%. (3/29) of patients with other autoimmune rheumatic diseases also possessed anti-sulphatide antibodies. The level of anti-sulphatide antibodies was significantly correlated with the levels of anti-double-stranded (ds) DNA antibodies (r = 0.634, P <0.001) and dextran sulphate-binding IgG (r = 0.407, P < 0.001). The serum levels of antibodies against sulphatide were correlated with a history of seizures or psychosis in patients with autoimmune rheumatic diseases. Gels coupled with polyanionic dextran sulphate, monoanionic sulphanilic acid and DNA were shown effectively to adsorb anti-sulphatide antibodies in the sera of patients with active systemie lupus erythematosus (SLE) and autoimmune chronic active hepatitis (AI-CAH). These results suggest that the observed reactivity with sulphatide is due to the presence of antibodies capable of reacting with various anionic molecules in the sera of patients with autoimmune rheumatic diseases as well as those with AI-CAH.