Shift of private and not of cross-reactive anti-DNA idiotypes in systemic lupus erythematosus.

The shift of private idiotype (Id) and cross-reactive Id (CRI) on anti-DNA antibodies in a lupus patient KE was investigated during a 7-year period. Anti-private Id and anti-CRI activities were separated by affinity chromatography from rabbit (R)-anti-Ids raised against KE anti-DNA antibodies during active (1/84) and inactive (4/90) stages of the disease. Anti-CRI isolated from the 84 R-anti-Id appeared to recognize binding site-related Ids that are shared with KE non-anti-DNA antibodies, unrelated lupus patients' sera, and certain normal sera. Id expression on serial serum samples of KE using these fractionated R-anti-Ids as probes showed that the 1/84 private Id expression declined while the 4/90 private Id expression gradually increased. Expression of the CRI showed a relatively stable pattern. These results suggest that anti-DNA populations detected by anti-private Id can shift, while populations expressing CRI may stay stable.