These innate immune cells can be recruited into the infection site as a result of elevated levels of cytokines, such as interferon (IFN)-γ, IL-1β, IL-4, and IL-6 (Cairo et al., 2010 ▶; Meyle et al., 2017 ▶; Ramadan et al., 2020 ▶). Here, IL4 is linked to infection.