[The neutrophil in human pathology]

The aim of this paper is to present few aspects of neutrophil role in some human diseases. New clinical and experimental findings and challenging hypothesis are briefly reviewed. The major role of neutrophils in host defense is a rapid response to invading microorganisms. To select their targets, neutrophils do not differentiate well between strange and host antigens without the support of soluble components of the immune system. The powerful weapons of neutrophils and the nonspecific response are the two major mechanisms by which they may damage normal tissue. The host-harming potential of the neutrophils is restricted by elimination of the primary event that initiates inflammatory response and by means that inactivate neutrophils. Inactivation of mediators and temporal adjustment in the pattern of chemokines production lowers the neutrophil influx; apoptosis provide safe clearance of dying neutrophils from the inflammatory site. Neutrophils become the major factor for tissue injury if these regulatory mechanisms are disturbed or if the acute episode cannot be resolved.