Distinct PGE2-responder and non-responder phenotypes in human mast cell populations: “All or nothing” enhancement of antigen-dependent mediator release

► We examined PGE2 enhancement of antigen-mediated degranulation in human mast cells. ► Cells from only half of donors responded to PGE2. ► The differences in responses were not due to differences in receptor expression. ► The differences reflect defective enhancement of calcium flux in non-responders. ► Results may have relevance to role of co-activating receptors in allergic disorders.