Nanotechnology has been gaining more and more momentum lately and the potential use of nanomaterials such as nanoparticles (NPs) continues to grow in a variety of activity sectors. Among the NPs, iron oxide nanoparticles (
IONs) have retained an increasing interest from the scientific community and industrials due to their superparamagnetic properties allowing their use in many fields, including medicine. However, some undesired effects of
IONs and potential risk for human health are becoming increasingly reported in several studies. Although many in vivo studies reported that
IONs induce immunotoxicity in different animal models, it is not clear how
IONs can alter the biology of primary human immune cells. In this article, we will review the works that have been done regarding the interaction between
IONs and primary immune cells. This review also outlines the importance of using primary immune cells in risk assessment of NPs as a reliable strategy for encouraging non-animal studies approaches, to determine risks that might affect the human immune system following different exposure scenarios. Taken all together, the reported observations help to get a more global picture on how
IONs alter the human immune system especially the fact that
inflammation, known to involve several immune cell types, is frequently reported as an undesired effect of
IONs.