CD5high and CD5low B cells (all CD20+) from CLL patient 4 and two healthy individuals were cell sorted, yielding >10,000 B cells per sample, and high-throughput BCR sequencing was performed (generating between 11,375 and 397,469 reads; Supplementary Fig. E4 and Supplementary Table E5, online only, available at www.exphem.org), along with BCR sequencing of the unsorted B-cell population. This evidence concerns the gene BCR and B-cell chronic lymphocytic leukemia.