Glucocorticoids induce basophil apoptosis.
BACKGROUND
Induction of apoptosis represents an important mechanism by which glucocorticoids (GCCs) exert their anti-inflammatory properties. The effects of GCCs on apoptosis have been determined in various immune cells and found to vary among different cell types. On the other hand, the effects of GCCs on apoptosis of basophils, active participants in allergic inflammation, have remained obscure.


OBJECTIVE
The objective of this study was to investigate the effects of GCCs on basophil apoptosis.


METHODS
Basophils were highly purified (purity, >97%) by Percoll density gradient centrifugation followed by negative selection. Cell status was determined by their ability to bind annexin V and exclude propidium iodide. DNA fragmentation was determined by flow cytometry.


RESULTS
Dexamethasone (DEX) significantly accelerated the decrease in live cells and increased the number of apoptotic cells in a time-dependent fashion. Light microscopy as well as DNA fragmentation assay confirmed the induction of apoptosis by DEX. A half-maximal effect was observed in a DEX concentration range from 10(-9) to 10(-8) mol/L. Sex steroids did not induce basophil apoptosis at all. DEX also induced basophil apoptosis in the presence of low doses of IL-3.


CONCLUSIONS
GCCs exert potent apoptogenic effects on basophils. GCC-mediated apoptogenic effects on basophils might have implications with respect to the mechanism of action of this class of drugs in allergic disorders.
Yoshimura
C
C
Department of Allergy and Rheumatology, University of Tokyo Graduate School of Medicine, Japan.
Miyamasu
M
M
Nagase
H
H
Iikura
M
M
Yamaguchi
M
M
Kawanami
O
O
Morita
Y
Y
Iwata
T
T
Yamamoto
K
K
Hirai
K
K
D017209:Apoptosis; D001491:Basophils / Q000187:drug effects*; D053938:DNA Fragmentation; D003907:Dexamethasone / Q000494:pharmacology*; D004347:Drug Interactions; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D006967:Hypersensitivity; D007377:Interleukin-3 / Q000494:pharmacology
D005938:Glucocorticoids; D007377:Interleukin-3; D003907:Dexamethasone