New Insights into “The Riddle of the Mast Cells”: Microenvironmental Regulation of Mast Cell Development and Phenotypic Heterogeneity

At no time in recent memory has it been so difficult to offer succint generalizations about the biology of the mast cell, or its role in health and disease. This situation is something of a paradox, since there have been significant recent advances in experimental approaches for analyzing mast cell development, biochemistry and function, and the application of these methods has already generated much important new data. However, some of these findings have required that certain widely held beliefs about the mast cell be reevaluated. Indeed, in virtually every facet of the cell’s natural history, from its differentiation and maturation to its biochemistry and function, recent work has revealed considerably more complexity than had previously been suspected to exist. To those involved in mast cell research, this exciting progress has raised hopes that “the riddle of the mast cells” (223), i.e., their specific roles in health and disease, might soon be solved. But to those whose acquaintance with the mast cell is more casual, the rapidly accumulating mass of new information may have caused no small amount of confusion.