These data fit very well to previous results reported on human CLL, where PDCD1 expressing T cells were found in close contact with CD274 expressing CLL cells in proliferation centres (Brusa et al, 2013), and the exhausted phenotype of these T cells was reversible by blocking PDCD1/PD-L interactions or by downmodulation of PDCD1 by immune-modulatory drugs (Brusa et al, 2013; Ramsay et al, 2012). This evidence concerns the gene PDCD1 and B-cell chronic lymphocytic leukemia.