Monocytosis eosinophils most often increase in the blood due to a wide range of diseases of an allergic nature (atopic and non-atopic allergic diseases, parasitosis, secondary proinflammatory mononucleosis, oncohematological diseases, bacterial and viral infections, as well as drug treatment). Radiation sickness leads to the same condition. Usually the percentage of monocytes is increased due to an increase in their total number, but also an increase in the percentage of macrophages in the blood up to 15% or sometimes up to 20%.