Differential expression of TNFAIP3 (A20) mRNA in leukemic LGLs compared with activated normal PBMCs. Total RNA (10 μg) from 9 LGL patients and from 5 healthy individuals was analyzed by Northern blot hybridization. The blot was probed with 800-bp fragment of TNFAIP3 or housekeeping gene (GAPDH). Northern blot analysis shows that TNFAIP3 is constitutively expressed in naive normal PBMCs (N PBMCs, lanes 1-5) and that the expression was down-regulated following PHA+IL-2 activation of normal PBMCs (AC PBMCs, lanes 6-7). In contrast, the expression of TNFAIP3 gene transcripts was much higher in RNA from LGL leukemia patients (TLGLs, lanes 8-16) compared with activated normal PBMCs. (White spaces have been inserted to indicate realigned gel lanes.)