Abstract: Objective To investigate the effect of one of the acute-phase proteins,fibrinogen,on the release of IL-1β and-8 by human peripheral polymorphonuclear leukocytes (PMN)and the possible role of fibrinogen during the destruction of periodontium. Methods Peripheral PMN were isolated by discontinuous density gradient centrifuging technique. The freshly isolated PMN were suspended in Hank's balaneed saline solution(1×109/L)supplemented with 0.5% BSA and 0.1% glucose.The levels of I-1β and-8 in the supernatants produced by cultured cells upon the addition of human fibrinogen at different concentrations were measured by ELISA technique. Results Incubated with human fibrinogen at 2 g/L or 10 g/L for different time periods,human peripheral PMN released significantly greater amount of IL-1β [(10.41±0.37)-(35.86±0.30)ng/L or(22.81 ± 0.45)-(57.77±2.08)ng/L]and IL-8[(93.90 ±13.95)-(2045.66±53.03)ng/L or(115.02±10.61)-(3858.69 ± 25.65)ng/L]than PMN without the stimulation offibrinogen(IL-1β,P<0.001,and IL-8,P≤0.016).The higher concentration of fibrinogen or the longer treatment time,the higher levels of IL-1β and -8 were released by PMN(P<0.001).Conclusions Fibrinogen induced the secretion of pro-inflammatory cytokines IL-1β and-8 by PMN and may be involved in magnification of the inflammatory response of periodontium and bone resorption.