IGHD and B-cell chronic lymphocytic leukemia: Indeed, we identified clonal rearrangement of IGHV-IGHD-IGHJ rearrangements (Table 1; supplemental Figure 2C-F) with unmutated IGHV genes (≥98% identity to germ line counterpart) in mice with CLL-like disease, indicating a monoclonal LPDs with unmutated IGHV genes.