Mast cells (MC) are phylogenetically old
cells which are distributed throughout the human
organism and, on the whole, occupy roughly the volume
of the spleen. MC have long been recognized as key
cells of type I hypersensitivity reactions. Several lines of
evidence, however, indicate that they not only express
critical effector functions in classic IgE-associated
allergic disorders, but also play important roles in host
defence against parasites, bacteria and perhaps even
viruses. Indeed, it is now clear that MC can contribute to
host defence in the context of either acquired or innate
immune responses through the release of a myriad of
pro-inflammatory and immunoregulatory molecules and
the expression of a wide spectrum of surface receptors
for cytokines and chemokines. Moreover, there is
growing evidence that MC exert distinct nonimmunological
functions, playing a relevant role in
tissue homeostasis, remodeling and fibrosis as well as in
the processes of tissue angiogenesis. In this review, we
provide a small insight into the biology of human MC
and their potential implications in clinical pathology.
