PLA2G2A and hereditary angioedema: However, the ability of MA (1) to modulate vascular permeability by catalyzing the production of vasoactive molecules; (2) to be activated by key mediators of HAE, such as BK and sPLA2; and (3) to modify opsonization capacity suggests that these cells play an important role in both asymptomatic and symptomatic phases of HAE.