1992 年 41 巻 1 号 p. 10-15
Although the concept of anti-phospholipid syndrome has been proposedin patients with SLE and other rheumatic diseases, the immunological mechanism is still controversial. Recently, the crossreactivity between anti-cardiolipin antibody and anti-ssDNA antibodies has been discussed in relation to this syndrome. In the present study, the specificity such as the avidity and the crossreactivity of anti-ssDNA antibodies was examined to find a clue to clarify the question why all of anti-cardiolipin antibody positive patients do not have any specific clinical features, thrombosis and spontaneous abortion. The avidity of IgG anti-ssDNA antibodies was examined by salt elution studies in solid phase ELISA. The avidity of anti-ssDNA antibodies tended to be lower in 10 patients with specific features than in other 10 patients without those features. The crossreactivity of affinity purified IgG anti-ssDNA antibodies was investigated by competitiveELISA. Purified anti-ssDNA antibodies from 4 patients without specific features were slightly inhibited by negatively charged phospholipids, cardiolipin and phosphatidylserine, whereas purified anti-ssDNA antibodies from 2 patients with specific features, who were considered to have anti-phospholipid syndrome, were little inhibited by these phospholipids. The above results suggest that the specificity of anti-ssDNA antibodies appears, at least partly, in different manners whether specific features are present or absent in anti-cardiolipin antibody positive patients. Moveover, anti-ssDNA anti-bodies and anti-phospholipid antibodies may form separate groups of antibodies in patients with anti-phospholipid syndrome.
