AICDA and B-cell chronic lymphocytic leukemia: To investigate AID activity in CLL, we developed a nested PCR approach to amplify the genomic region spanning the rearranged VDJ gene downstream to the Sμ region using clone-specific V-gene primers and Sμ-specific consensus primers on genomic DNA from two IgV-UM (IgV-UM #1, 2) and two IgV-Mut samples (IgV-Mut #3, 4).