OLFM4 and Sepsis: Acute intestinal mucositis is a common off-target effect of chemotherapy, leading to co-morbidities such as vomiting, diarrhea, sepsis, and death.1 These complications can arise secondary to loss of active intestinal stem cells (aISCs), which live in the crypt base and produce all intestinal epithelial cells.2 These cells are identified by high expression of olfactomedin 4 (Olfm4) and leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5).3 aISCs live in close proximity to the gut microflora.