CTLA4 and B-cell chronic lymphocytic leukemia: Several studies showed that ibrutinib is capable of modulating the immune dysfunction characterizing CLL patients by increasing Th1 and Th17 subsets (78, 79) and possibly reversing the exhausted T-cell phenotype associated to the expression of PD-1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) on lymphocytes (79, 80).