Figure 1.

a–d. The original sample, wash through, and eluent fractions from the four selected positive SLE/APS samples were tested on Assay A (blue) and Assay B (red). IgA anti-β₂ GPI reactivity is expressed as optical density (OD) minus background. Eluent fractions containing purified IgA from all the four samples reacted only on IgA anti-β₂ GPI assay A (blue).

Affinity purification of IgA antibodies: SLE/APS (a), SLE/APS (b), SLE/APS (c), SLE/APS (d)

SLE: systemic lupus erythematosus; APS: antiphospholipid syndrome