*2.1.3 Anti-*β*2 glycoprotein antibodies*

Anti-β2GPI antibodies are specific to the β2GPI, a cofactor with affinity for anionic phospholipids which inhibits in vitro the activation of prothrombin and the ADP-dependent platelet aggregation [22].

Both aCL and anti-β2GPI antibodies of IgM and IgG isotypes are detected by immunological assays following the ISTH subcommittee recommendation [23]. IgG and IgM isotype, at medium-high titer have greater clinical significance [24].
