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Mast cell granule composition and tissue location - a close
correlation
W.J. Beil1, M. Schulz2 and U. Wefelmeyer3
1Department of Pathology, Vienna University,
Vienna, Austria, 2Department of Gastroenterology and Hepatology,
Medizinische Hochschule, Hannover, Germany and 3Department of
Internal Medicine, Nordstadtkrankenhaus, Hannover, Germany
Offprint requests to: Dr.
W.J. Beil, Institut für Klinische Pathologie, Allgemeines
Krankenhaus, Währinger Gürtel 18-20, 1090 Wien, Austria.
Fax: 43 1 4053402
Summary. This
review provides a survey on mast cell heterogeneity, with aspects
differing in humans and rodents or which are subject of conflicting
evidence being discussed in greater detail. Mast cell subsets
have been first defined in rats by their fixation and dye-binding
properties, and detailed studies in humans and pigs reveal very
similar observations. The dye-binding properties of rat mast cell
subsets are causally related to the absence or presence of heparin
in their granules. In humans, this relation has not been shown.
Rodent mast cell subsets store different chymase-isoforms. In
contrast, just a single chymase has been defined in humans, and
mast cells are classified by the presence or relative absence
of this chymase. Different investigators find quite different
proportions of chymase-positive to chymase-negative mast cells.
Tryptase(s) are found in most or every human mast cell, but in
rodents, they have hitherto been essentially localised to mast
cells in connective tissues. Human mast cell subsets may also
be defined by their expression of receptors such as C5aR and possibly
the ß-chemokine receptor CCR3; the CCR3 expression seems
to be related to the human mast cell chymase expression. Ultrastructural
studies are helpful to distinguish human mast cell subsets, and
allow to distinguish between chronic and acute activation.
The phenotypical characteristics may change in association with
inflammation or other disease processes. Studies in humans and
pigs show changed dye-binding and fixation properties of the granules.
Experimental rodent infection models reveal similar changes of
chymase isoform expression. Human lung mast cells have been reported
to strongly upregulate their chymase content in pulmonary vascular
disease. This line of evidence can explain some inconsistent information
on mast cell heterogeneity and may help to understand the physiological
role of mast cells. Histol. Histopathol. 15,, 937-946 (2000)
Key words: Mast
cells, Fixation, Tryptase, Chymase, Heparin
DOI: 10.14670/HH-15.937
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