CD86 is a reliable marker to distinguish HSCs and MPPs from committed progenitors in inflammatory conditions. Immunophenotypes typically used to identify HSPCs have been determined largely in the context of steady-state hematopoiesis (left). However, Sca-1 expression is induced in a type I IFN-dependent manner on committed progenitors that typically do not express Sca-1, making them difficult to identify in inflammatory contexts. Replacing Sca-1 with CD86 allows efficient identification of committed progenitors, even in conditions associated with inflammation (right). The depicted sizes of HSPC populations in the LK, LSK, and L86K compartments indicate the relative frequencies of cells in each compartment in each context (steady state hematopoiesis or infection/inflammation), and is not intended to be indicative of absolute cell numbers. CMP, common myeloid progenitor; MPP, mulipotent progenitor; LT-HSC, long-term HSC; ST-HSC, short-term HSC.