We present a case of an adult patient with new-onset severe, idiopathic, protein-wasting enteropathy, in whom an extensive immunological workup was performed. We found a lack of dendritic cell (DC) subsets in the blood and bowel, as well as elevated circulating TGF-beta levels and decreased numbers of circulating FOXP3+ regulatory T cells with diminished CTLA4 expression. She failed to respond to glucocorticoids and infliximab, and instead developed a constellation of opportunistic infections, including CMV ileitis, Mucormycosis, and Pneumocystis carinii pneumonia, and ultimately passed away. While the cause of her lack of DCs is unknown, this data suggests a key role for these cells in both regulating mucosal immunity and promoting effective cell-mediated immunity against pathogens in humans.