Properties of antinuclear antibodies that cross-react with plasma membranes.

Certain human antinuclear antibodies (ANA) cross-react specifically with the surface membrane of human leucocytes. In the present work these cross-reacting (X) ANA could be eluted directly from viable leucocytes isolated from three patients. The plasma membrane antigen recognized by X-ANA appeared phylogenetically highly conserved since it was present on viable HeLa cells and cells from mouse and rabbit spleen, rat liver, and the slime mould Physarum polycephalum. X-ANA did not react with the plasma membrane of nucleated bird erythrocytes or human erythrocytes or thrombocytes. The same X-ANA subset reacted with the various cells. The presence of X-ANA correlated strongly (P less than 0.01) with antibodies against a HeLa cell surface antigen. The nuclear antigen recognized by X-ANA was present in all species examined, including bird erythrocyte nuclei and nuclei of Physarum polycephalum. Native or denatured DNA, RNA or a saline extract of nuclei did not inhibit the binding of X-ANA to cell nuclei.