Beclomethasone decreases elevations in phosphodiesterase activity in human T lymphocytes

Background: We recently reported that CD4+ T cells that have been activated in vivo or in vitro contain elevated cyclic adenosine monophosphate (cAMP) phosphodiesterase (PDE) activity. Since both phosphodiesterase inhibitors and glucocorticoids have anti-inflammatory activity, we sought to investigate the effect of beclomethasone on PDE activity. Methods: PDE activity was measured in CD4+ T cells after 24 h of culture with beclomethasone. Cells were obtained from the peripheral blood of nonatopic persons (nCells), pre-seasonal (pCells), seasonal (within the first 2 weeks; sCells) and mid-seasonal (mCells) allergic rhinitics and asymptomatic allergic asthmatics (aCells). In addition, the effect of beclomethasone on Th2 cell lines and cells that had been activated in vitro with PHA or interleukin (IL)-2 was determined. Results: PDE activity was decreased in a concentration-dependent manner by incubation of mCells, Th2 lines and PHA or IL-2-activated CD4+ T cells with beclomethasone (p <0.05). However, beclomethasone did not modulate PDE activity in nCells, pCells, sCells, or aCells. Conclusions: Beclomethasone only decreases cAMP PDE activity in CD4+ T cells when it is increased by cell activation either in vitro or in vivo. Copyright (C) 2000 S. Karger AG, Basel.