Similar transcription factor expression in AID^high and AID^low CLL cells. (A) Quantitative RT-PCR analysis of AID expression in RAN (▾, n = 7) and UNI (■, n = 16) purified CD19⁺ B-cell fractions. Expression was normalized with HPRT, and relative expression in wild-type B-cell fractions was set to 1. (B) Expression of indicated transcription factors as measured by quantitative RT-PCR in AID^high (▨, n = 5; relative expression > 2, panel A) and AID^low (□, n = 11; relative expression < 2). Expression was normalized with HPRT, and relative expression in RAN B-cell fractions was set to 1. Mean values and SEM are given. * Significant differences between AID^low and AID^high CLL cells (P < .001, t test).