ABSTRACT
Platelet-activating factor (PAF) is considered a potent mediator in various pathological and physiological reactions (1). Evidence has also been accumulating that PAF is involved in the regulation of cellular immune response (2). For instance, large granular lymphocytes were shown to release PAF on activation (3). Varying results concerning the effect of exogenous PAF on lymphocyte proliferation have been presented. Thus, Rola-Pleszczynski et al. (4) reported that PAF inhibited the proliferation of human peripheral blood lymphocytes. Patrignani et al. (5) reported that PAF caused a dose-dependent increase of prostaglandin E2 and leukotriene B4 synthesis in peripheral blood mononuclear cells. It was also shown that PAF partially
down-regulated expression of the CD2 and CD3 antigens on human peripheral T cells (6).
