Abstract
Background: Neutrophil (PMN) infiltration of the lung is characteristic of ARDS. Interleukin-8 (IL-8) plays a central role in the recruitment of PMN to the lung and their subsequent activation. This study examines PMN migratory activity in response to IL-8, over the first 24 hours of admissions following major trauma.
Methodology: Study Population: Adult blunt trauma victims with ISS> /=18
PMN Migraoty Activity: PMN were isolated from citrated blood at admission, 8 and 24 hours later. The number of PMN migrating across porous tissue culture inserts in response to defined concentrations of IL-8 (zero, 10, 30 & 100ng/ml) were quantitated by peroxidase assay.
Results: Significantly greater numbers of trauma patients PMN migrated to concentrations of IL-8 (30& 100ng/ml) at each time point, when compared to normal volunteers (Mann-Whitney-U Test p< 0.05). At admissions, and 8 hours later, PMN from those who later developed ARDS exhibit an enhanced migratory response to high concentrations of IL-8, in contrast to the noraml physiological attenuation of migration seen in both the remaining trauma patients (NAD) and normal volunteers (NLV).
Discussion: These data indicate that major trauma fundamentally alters the migratory capacity of circulating PMN. Within 2 hours of admission, PMN show a unique pattern of activation in those who later develop ARDS, possibly due to alteration in IL-8 receptor expression, affinity or downstream signalling. These findings suggest that limiting PMN sequestration in the lung may represent a novel therapeutic target.
The abstracts were prepared by Mr Ray Moran. Correspondence should be addressed to him at the Irish Orthopaedic Association, Secretariat, c/o Cappagh Orthopaedic Hospital, Finglas, Dublin
