CD8A and paroxysmal nocturnal hemoglobinuria: Considering the extensive evidence that shows that autoimmune attacks in AA are mainly due to CD8(+) T-cell reaction [40,41] and the studies by Gargiulo et al., who analyzed the receptors’ structure and found similar sequences in CD8(+) T-cells from PNH patients but not from normal controls, supporting their role in the autoimmune attack [42], it can be assumed that T-cell immune escape mechanisms are the major characters in PNH selection.