Strong correlation of high EBNA-1-IgG levels with edematous attacks involving upper airway mucosa in hereditary angioedema due to C1-inhibitor deficiency

► We measured anti-EBNA-1 IgG titers in 107 patients with hereditary angioedema. ► High anti-EBNA-1 levels strongly correlated with frequency of upper airway attacks. ► High anti-EBNA-1 levels correlated with the consumption of C1-inhibitor concentrate. ► Underlying mechanisms of upper airway attacks may differ from that of other types of attacks. ► Anti-EBNA-1 IgG levels may be suitable for the prediction of upper airway attacks.