Amplicons of the expected length (99 bp for AID and CD21L, and 171bp for β-actin, Figure 2B) were seen in samples positive for AID and CD21L by QT-PCR (lane 2) and human lymph node (lane 5), but not in RA samples negative for AID and CD21L (lane 3) or in the negative control (lane 4, cDNA from CD3 sorted cells). This evidence concerns the gene ACTB and rheumatoid arthritis.