The effect of purified IgG from healthy controls or patients with lupus nephritis on tyrosine phosphorylation in podocytes at two different IgG concentrations. The effect of purified IgG from healthy controls or patients with lupus nephritis on tyrosine phosphorylation in podocytes at two different IgG concentrations. Podocytes were grown in medium containing purified IgG from patients with LN, or normal controls. Lysates were blotted with antiphosphotyrosine antibody and equal loading of protein confirmed with GAPDH. The groups were compared using the Mann–Whitney test for significance. (A) Medium containing 100 μg/mL IgG, with representative western blots. No difference was seen between normal control and lupus nephritis IgG-exposed cells. (B) Medium containing 1.5 mg/mL IgG, with representative western blots. Exposure to this concentration of IgG from patients with lupus nephritis led to a relative reduction in protein tyrosine phosphorylation compared with healthy control IgG. Jessica J Manson et al. Lupus Sci Med 2014;1:e000013 ©2014 by Lupus Foundation of America