The role of influenza virus hemagglutinin in blood anticoagulation processes

: Influenza virus hemagglutinin (HA) possesses anticoagulant and fubrinolytic activities and affects such blood clotting factors as fibrinogen and factor XIII in vitro and in vivo. Computer analysis of HA structure of avian, animal, and human type 1 influenza viruses showed 1 or 2 sites of amino acid sequences similar to plasminogen activator. These sites proved to be highly conservative for each virus subtype, irrespective of the source and year of isolation of the strain. Evolution relationships with respect to this sign were detected between the studied viruses.