Effects of chronic (8 months) hIVIG treatment on amyloid pathology in APdE9 mice. Brain samples were analyzed from 16 hIVIG treated and 15 saline treated mice. Chronic hIVIG treatment elevated soluble Aβ40 (A) and Aβ42 (B) levels in the hippocampus. In contrast, levels of hippocampal insoluble Aβ40 (C) and Aβ42 (D) levels did not change significantly. There was no significant treatment effect on amyloid load (relative amyloid plaque area) in the hippocampus as visualized by WO2 antibody (E) or on dense core amyloid plaque area (F). Serum Aβ40 levels (G) in saline (n = 14) and hIVIG (n = 14) treated mice did not differ, either. All data are given as mean ± SEM, * P < 0.05, ** P < 0.01 as calculated by student’s t-test.