There were no significant difference between stimulated and non-stimulated CLL cells neither on the PD-1 transcript level (1/ΔCt of 0.22 vs. 0.24, respectively, p = 0.54, Figure 3A) nor surface protein presence (MFI PD-1, 82.22 vs. 69.34, p = 0.48, Figure 3B). This evidence concerns the gene PDCD1 and B-cell chronic lymphocytic leukemia.