Leukotriene B sub(4) production by blood neutrophils in allergic rhinitis - Effects of cetirizine

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 leukotriene B sub(4) (LTB sub(4)). We had previously observed increased production of LTB sub(4) by neutrophils in patients with allergic rhinitis and discussed the role of granulocyte macrophage-colony stimulating factor (GM-CSF) priming. Some antihistaminic compounds were shown to diminish the production of leukotrienes by neutrophils. In a first step, we evaluated in ex vivo and in vitro studies, the effects of cetirizine on LTB sub(4) production by blood neutrophils from allergic and healthy subjects. In a second step, we studied the in vitro effect of cetirizine on LTB sub(4) production by neutrophils from healthy subjects during GM-CSF priming of these cells. Neutrophils from both populations were purified from venous blood and LTB sub(4) production was measured using high performance liquid cromatography (HPLC) method. In ex vivo studies, cetirizine treatment induced a decreased LTB sub(4) production by neutrophils in allergic rhinitis. This effect of decreased LTB sub(4) production was reproduced in vitro with 10 super(-8)-10 super(-6) M citirizine. Nevertheless, this anti-H1 compound had no effect on neutrophil priming with GM-CSF. As LTB sub(4) is an important chemotactic factor, Cetirizine could act on inflammatory cell recruitment by inhibiting LTB sub(4) production by neutrophils.