Effects of amorphous silica particles (SPs) on total and Dermatophagoides pteronyssinus (Dp)-specific IgE production in plasma. NC/Nga mice were intradermally injected on the ventral side of both ears with Dp alone or Dp plus SPs in PBS on days 1, 3, 5, 7, 9, 11, 13, 16, and 18. To evaluate AD severity, plasma was collected 24 h after the last intradermal injection and analyzed by ELISA for total and Dp-specific IgE (A and C). A regression analysis of total IgE was also performed (B). Data are presented as mean ± SE of 4-5 animals per group. The results are representative of two separate experiments. *P < 0.05 vs. Dp group.