Influence of NaCl concentration on the recognition of β₂-GPI by anti-β₂-GPI IgG antibodies. Plasma-purified β₂-GPI and recombinant β₂-GPI were coated to hydrophobic (A) and hydrophilic (B) plates. Subsequently, the plates were blocked with 4% BSA/TBS/Tween and incubated with (type A) patient plasma that was diluted in blocking solution with either 150 mM NaCl or 5 M NaCl. To detect the bound patient IgG antibodies, the plates were incubated with an alkaline-phosphatase-labeled goat anti-human IgG antibody. PnPP was used as coloring substance. Error bars represent mean ± SEM of quadruplicate points.