IL4 and osteogenesis imperfecta: In addition, increased levels of several cytokines in the olfactory cleft have been correlated with OI, elevated levels of IL-2, IL-5, IL-6, IL-10, and IL-13 are indeed associated with reduced test scores for smell identification and olfaction is found to be strongly correlated with levels of cytokines IL-5 and IL-13, although the role of the IL-4 and IL-13 pathways and their possible regulatory impacts on neurogenesis and homeostasis of olfactory neurons have not been determined yet [20].