Circulating levels of platelet α-granule cytokines in trauma patients.

OBJECTIVE AND
DESIGN: To elucidate whether platelets differentiate cytokine release following trauma, we prospectively measured three major platelet-derived cytokines in 213 trauma patients on hospital arrival.
METHODS: We measured plasma levels of the anti-inflammatory β-thromboglobulins (βTGs), transforming growth factor-β1 (TGFβ1) and the pro-inflammatory platelet factor 4 (PF4) cytokines. We also measured soluble glycoprotein VI (sGPVI), procoagulant platelet microparticles (PMPs) and white blood cell (WBC) counts, and evaluated in vitro platelet function in primary and secondary haemostasis by aggregometry and thromboelastometry, respectively. We evaluated associations of each cytokine by multivariate regression including injury severity score (ISS), WBC counts, sGPVI and platelet counts as explanatory variables.
RESULTS: Severely injured patients (ISS > 15) had higher levels of βTGs and TGFβ1 (both p < 0.01) but lower levels of PF4 (p = 0.02). GPVI and PMPs levels correlated with TGFβ1 and PF4 whereas we found no significant association between cytokine levels and measures of haemostasis. By multivariate regression, a high WBC count was associated with high levels of TGFβ1 (p = 0.01) and βTGs (p < 0.01) but with low levels of PF4 (p = 0.03).
CONCLUSION: Severely injured patients had higher levels of βTGs and TGFβ1 but lower levels of the PF4; a high WBC count predicted this anti-inflammatory profile of platelet cytokines.