CTLA4 and B-cell chronic lymphocytic leukemia: We found that CTLA-4, TIGIT, LILRB4, and CD276 showed statistically significant increased expression in malignant B cells as compared to normal B cells (CTLA-4, p val = 0.047; TIGIT, p val = 0.016; CD276, p val = 0.016; LILRB4, p val = 0.016 [Wilcoxon paired signed-rank test]), while CD2 surface expression was not detectable neither in normal nor CLL B cells (Fig. 6b; Additional file 1: Figure S9b).