CTLA4 and B-cell chronic lymphocytic leukemia: EBV load correlated positively with unfavorable prognostic markers of CLL and the expression of CTLA-4 on CD3+ lymphocytes (r = 0.5339; p = 0.027, Figure 2A) and CD86 on CD19+ cells (r = 0.6950; p < 0.001, Figure 2B).