Fcα/μR, also known as is CD351 (Cluster of Differentiation 351), is an Fc receptor that binds IgM with high affinity and IgA with a 10-fold lower affinity. In mice the receptor is expressed on macrophages, follicular dendritic cells, marginal zone and follicular B cells and kidney tubular epithelial cells. In humans expressed has been described on intestinal lamina propria cells, Paneth cells, follicular dendritic cells in tonsils, activated macrophages and some types of pre-germinal centre IgD+/CD38+ B cells.
^Yang, Xi; Zhao, Qing; Zhu, Liping; Zhang, Wei (May 2013). "The three complementarity-determining region-like loops in the second extracellular domain of human Fc alpha/mu receptor contribute to its binding of IgA and IgM". Immunobiology. 218 (5): 798–809. doi:10.1016/j.imbio.2012.09.004. PMID23182711.