Effects of dialysis on the HCQ-mediated reduction of aPL IgG–β2GPI complex binding. Mixtures of aPL IgG (0.5 mg/mL) and β2GPI (5 μg/mL) were incubated overnight with the 2 concentrations of HCQ or control buffer, and the proteins were then dialyzed against buffer before exposure to the bilayers. (A) Incubation of aPL IgG–β2GPI with HCQ at 1 μg/mL, without dialysis, significantly reduced the complex binding; dialysis of the mixture incubated with HCQ (1 μg/mL) against buffer restored the binding of the complexes to phospholipid. (B) Similar results with HCQ at the higher concentration of 1 mg/mL.