Although extensive investigations into the role of neutrophils and their products in tissue injury have been conducted, very little work has been carried out on the role of polypeptide cytokines in the regulation of neutrophil-mediated tissue damage. A range of cytokines are known to promote a wide variety of functions of the neutrophil, including neutrophil adhesion, surface receptor expression, ODRS production, and release of lysosomal constituents. Evidence has been presented to show that these products, either singly or in combination, cause tissue injury. At this stage, TNF alpha and TNF beta are cytokines which have been shown to regulate neutrophil tissue injury. From this work it is suggested that TNFs promote neutrophil-mediated tissue damage.