Anti-FVIIa activity of plasma antithrombin (AT) in healthy control samples and carriers of mutations affecting the glycosylation at Asn224. (A) Formation of FVIIa-antithrombin complexes (FVIIa-AT) in vitro by incubation of plasma from carriers of both variants and a control subject, with recombinant FVIIa and UFH. FVIIa-AT complexes (C) and free antithrombin were detected by Western blotting. The image shows representative cases. Values from densitometry analysis of FVIIa-AT, free AT, and total AT are indicated. *arbitrary units. (B) Violin plots of FVIIa-AT complexes and ratio FVIIa-AT/total AT determined by densitometry in 3 carriers of the p.Asn224His and p.Glu227Lys variants and 4 healthy control samples after incubation with FVIIa and UFH. a.u., arbitrary units. *P < .05. (C) Violin plots of FVIIa-AT complexes determined by a specific ELISA in the same samples. The ratio FVIIa-AT/total AT is also shown. *P < .05.