Expression of AID-splicing variants in CLL B cells. (A) Purified CLL B cells from 3 patients were limiting diluted into 96-well PCR plates at the densities of 1000 cells/well (depicted in top panels). The wells filled with various colors indicate where AID was positively detected, and the color codes show the identities of the AID PCR products. (Bottom panels) DNA gel images showing the amplified AID variants from those PCR-positive wells. Data shown are representative of a total of 6 B-CLL patients studied in this manner. (B) Overexpression of AID-splicing variants in CLL B cells. (Top panel) A composite gel image of AID RT-PCR; while the bar chart (bottom panel) is the quantitation of the same image by densitometry. The Ig VH genes in CLL B cells shown in lanes 5, 6, 11, and 13 were mutated and those shown in lanes 7 to 10 and 12 were unmutated.