Occurrence of complement-fixing antibodies reactive with normal tissue constituents in normal and disease states.

Serum substances that react with mammalian tissues, present in individuals with certain acute and chronic diseases, have been the object of several recent reviews (2-4). In addition, complement-fixing substances against human tissue have been demonstrated recently in patients with acute viral infections and systemic lupus erythematosus (5). The question of whether these substances are true antibodies, formed as a result of antigenic stimulation, has often been raised. As far as they have been characterized, they possess the attributes of typical antibodies formed in response to injections of foreign materials: relative specificity, occurrence in the globulin fraction of serum, ability to fix complement, and relative heat stability. It would seem reasonable, therefore, to regard them as antibodies. The implied detrimental effect of an immunological response to one's own antigens and the subsequent production of tissue antibodies was dramatized by Ehrlich with the expression horror autotoxicus. Yet Kidd and Friedewald (6) have demonstrated the existence of tissue antibodies in the sera of normal rabbits that fix complement with constituents of normal rabbit tissue cells. The present work has considered the incidence of these natural antibodies in other species in addition to the rabbit and their possible reactivity against calf thymus as well as rabbit tissue. In addition, the level of these antibodies in human disease and in animals subjected to various experimental conditions has been determined. Finally, certain properties of tissue antibodies have been investigated.