Immunoglobulin kappa chain receptor editing in systemic lupus erythematosus

To determine whether receptor editing of Vκ genes was involved in the pathogenesis of systemic lupus erythematosus (SLE), the usage of Vκ and Jκ gene elements from individual peripheral CD19⁺ B cells obtained from a patient with untreated SLE was examined. No differences in the Vκ and Jκ gene usage in the nonproductive gene repertoire of this SLE patient were noted compared with the distribution of genes found in normal adults. However, an increased usage of Jκ5 segments, and a significant overrepresentation of the Vκ1 and Vκ4 families, especially the L15, O14/O4, and B3 genes characterized the productive Vκ gene repertoire of the SLE patient. Furthermore, Jκ5-containing Vκ gene rearrangements in the productive but not the nonproductive repertoire manifested significantly fewer mutations compared with Vκ genes recombined with Jκ1-4. These data are consistent with the conclusion that receptor editing of Vκ is much more apparent in this SLE patient than in normals and suggest that a deficiency in this means to counteract the emergence of autoimmunity is not an essential feature of SLE.