Levocetirizine modules the cellular networks of allergic and inflammatory processes

A profound tissue remodeling occurs during allergic inflammatory reactions, e. g., asthma and atopic dermatitis, Multiple cells and inflammatory components are involved. We studied the effect of levocetirizine on human peripheral granulocytes (PMN) and, lymphocytes, monocytes, and basophils (LMB). The cells were preincubated with various concentrations of levocetirizine and subsequently stimulated with the bacterial peptide fMLP, phorbolmyristate acetate (PMA), sodium fluoride (NaF), or staphylococcal enterotoxin B (SEB). Results were obtained for the surface expression of the chemotaxin receptors CXCR2, the fMLP-R, CD62 ligand, and CD11b by FACS analysis. The synthesis and release of interleukin-8, TNF-alpha, LTB4, PGE(2) were detected by ELISA and the chemotaxin receptors CXCR1, 2, and the Toll-like receptors 2, 4, 9 were analyzed by RTPCR. The results show that levocetirizine induces a strong and distinct anti-inflammatory activity suggesting defined receptor pathways of modulation for the individual mediators as well as surface receptors.