Antitissue antibodies in monozygotic twins with systemic lupus erythematosus.

The familial occurrence of systemic lupus erythematosus (SLE) is well established (Brunjes, Zike, and Julian, 1961; Leonhardt, 1964), and even monozygotic twins with this disease have been reported by several workers (Davis and Gutridge, 1951; Wagenhals and Burgeson, 1958; Blumenfeld, Kaplan, Mills, and Clark, 1963; Joseph and Zarafonetis, 1965; Lieberman, Heuser, Hanson, Kornreich, Donnell, and Landing, 1968). These observations have been considered to indicate that genetically determined factors may have an important role in the aetiology of SLE. The following is a report of a pair of monozygotic twins both of whom had SLE with a very similar clinical picture and who, in addition, had a very similar antitissue antibody pattern.