Cross-reactive anti-DNA antibody idiotypes have been identified on tissue-bound immunoglobulins in a study of renal biopsies from 26 systemic lupus erythematosus (SLE) patients. 12 (46%) biopsies were shown to have one or both the idiotypes tested for by anti-idiotypic reagents. The idiotypes were identified in the glomerular basement membrane, the mesangial cell cytoplasm, and in focal tuft proliferations. In contrast, in none of 24 immunoglobulin-positive disease control biopsies could either idiotype be demonstrated. Blocking studies in two patients indicated that the idiotypes were on anti-DNA antibodies. These findings indicate that some tissue-bound auto-antibodies are derived from related families of high-frequency germ line genes that are expressed in SLE patients. The potential role of anti-idiotypic therapy in SLE is discussed.
D A Isenberg, C Collins