Inhibitory molecules are up-regulated in CLL cells and linked to poor patient prognosis. (A) IHC mean intensity expression analysis ± SEM of CD200, CD274, CD276, CD270 on CD20⁺ cells, and CD279 and CD272 expression on CD3⁺ T cells in CLL patient samples compared with reactive lymph node samples. Representative high-power 40× magnification and 63× inset images are shown. (B) MFI or percent positive expression analysis of inhibitory ligands and receptors on peripheral blood CD19⁺ cells (CLL cells compared with healthy B cells) or autologous CD3⁺ T cells from CLL patients or age-matched healthy donors. Columns show the means ± SEM from 12 patients. *P < .05; **P < .01.