 In order to avoid destruction by the immune system and thrive, the "Leishmania" 'hides' inside its host's cells.This location enables it to avoid the action of the humoral immune response (because the pathogen is safely inside a cell and outside the open bloodstream), and furthermore it may prevent the immune system from destroying its host through nondanger surface signals which discourage apoptosis.The primary cell types "Leishmania" infiltrates are phagocytotic cells such as neutrophils and macrophages.