Leukotriene B4 production by blood neutrophils in allergic rhinitis—effects of cetirizine

Background: Mucosal inflammatory processes in late phase of allergic diseases involve cytokine production, cell adhesion molecule overexpression and release of inflammatory mediators with chemotactic activity, such as leukolriene B₄ (LTB₄), We had previously observed increased production of LTB₄ by neutrophils in patients with allergic rhinitis and discussed the role of granulocyte macrophage-colony stimulating factor (GM-CSF) priming. Some antihislaminic compounds were shown to diminish the production of leukotrienes by neutrophils. Objective: In a first step, we evaluated in ex vivo and in vitro studies, the effects of cetirizine on LTB₄ production by blood neutrophils from allergic and healthy subjects. In a second step, we studied the in vitro effect of cetirizine on LTB₄ production by neutrophils from healthy subjects during GM-CSF priming of these cells. Methods: Neutrophils from both populations were purified from venous blood and LTB₄ production was measured using high performance liquid cromatography (HPLC) method. Results: In ex vivo studies, cetirizine treatment induced a decreased LTB₄ production by neutrophils in allergic rhinitis. This effect of decreased LTB₄ production was reproduced in vitro with 10^?8–10^-6 cetirizine. Nevertheless, this anti-Hl compound had no effect on neutrophil priming with GM-CSF. Conclusion: As LTB₄ is an important chemotactic factor, Cetirizine could act on inflammatory cell recruitment by inhibiting LTB₄ production by neutrophils.