Decreased leukotriene release from neutrophils after severe trauma: Role of immature cells

Polymorphonuclear granulocytes (PMN) play a key role in host defense agains t microbial infections. After severe trauma PMN show cellular dysfunctions including chemotactic migration, phagocytosis, and bacterial killing. In th ese settings the contribution of the cellular matruation stage compared to functional activities has not been investigated. Polymorphonuclear granuloc ytes are potent producers of lipid mediators via the 5-lipoxygenase (5-LO) pathway (leukotrienes, LTs) which exert important proinflammatory and immun oregulatory activities. We analyzed leukotriene generation from PMN-fractio ns (N = 23) of 15 polytrauma patients in comparison to 17 healthy donor cel l fractions and correlated this lipid mediator release to the hematopoietic maturation stage of respective PMN. Polymorphonuclear granulocytes were is olated from EDTA-anticoagulated peripheral blood employing a one step proce dure based on a discontinuous double Ficoll-gradient. Cells (5 x 10(6)/500 mul phosphate-buffered saline) were stimulated for 20 min at 37 degreesC wi th 1 muM Ca-ionophor A23187 in the presence of 1 mM Ca++ and 0.5 mM Mg++. L eukotrienes were analyzed by reversed-phase HPLC. Expression of 5-lipoxygen ase (5-LO) was additionally determined by Western blot. Maturation stage of PMN was quantitated by Pappenheim-staining of cell smears. After polytraum a the generation of leukotrienes from PMN was individually diminished. Synt hesis of enzymatically formed metabolites (LTB4, OH-LTB4 and COOH-LTB4) was concomitantly reduced. The decreased leukotriene synthesis strongly correl ated (r(2) = 0.907, P < 0.0001) to the occurrence of immature PMN (mostly b and cells). The expression of 5-lipoxygenase in PMN fractions consisting ma inly of band cells was decreased. Our results provide evidence that posttra umatic granulocyte dysfunction is partly due to immature functional cell ca pacities.