Beclomethasone decreases elevations in phosphodiesterase activity in humanT lymphocytes

Background: We recently reported that CD4(+) T cells that have been activat ed in vivo or in vitro contain elevated cyclic adenosine monophosphate (cAM P) phosphodiesterase (PDE) activity. Since both phosphodiesterase inhibitor s and glucocorticoids have anti-inflammatory activity, we sought to investi gate the effect of beclomethasone on PDE activity. Methods: PDE activity wa s measured in CD4(+) T cells after 24 h of culture with beclomethasone. Cel ls were obtained from the peripheral blood of nonatopic persons (nCells), p re-seasonal (pCells), seasonal (within the first 2 weeks; sCells) and mid-s easonal (mCells) allergic rhinitics and asymptomatic allergic asthmatics (a Cells). In addition, the effect of beclomethasone on Th2 cell lines and cel ls that had been activated in vitro with PHA or interleukin (IL)-2 was dete rmined. Results: PDE activity was decreased in a concentration-dependent ma nner by incubation of mCells, Th2 lines and PHA or IL-2-activated CD4(+) T cells with beclomethasone (p<0.05). However, beclomethasone did not modulat e PDE activity in nCells, pCells, sCells, or aCells. Conclusions: Beclometh asone only decreases cAMP PDE activity in CD4(+) T cells when it is increas ed by cell activation either in vitro or in vivo. Copyright (C) 2000 S. Kar ger AG, Basel.