A 16/6 idiotype-positive anti-DNA antibody is encoded by a conserved VH gene with no somatic mutation.

Recently, the heavy chain of 16/6 idiotype-positive human anti-DNA antibodies was found to be similar, but not identical, to the VH26 gene. We resequenced the VH26 gene and found that its coding sequence is actually identical to the complementary DNA sequence of the anti-DNA antibodies previously described. Together with the previous data, our findings demonstrate that some human autoantibodies are encoded directly by immunoglobulin V region genes, and that these V region genes are remarkably conserved in populations.