CCL11 and Increased total eosinophil count: The eosinophilia of NiO NPs with a delayed-time frame (3 and 4 days after instillation) and immediate (1 day after instillation) eosinophilia by NiCl2 might provide an important clue for the mechanism of the immediate eotaxin release by highly soluble NPs (e.g., CoO, CuO, and ZnO) [7, 8].