CD200 and B-cell chronic lymphocytic leukemia: Notably, p66Shc reconstitution did not affect the expression of the inhibitory ligands CD200, CD276 and CD270 (Supplementary Figure S4) which, similar to PD-L1, are upregulated in CLL cells and contribute to the IS defects observed in CLL (Ramsay et al., 2012), ruling them out as mediators of the p66Shc-dependent IS dysfunctions.