Diminished plasma levels of GPIb-α predict mortality in a prospective ARDS cohort

Activated immune cells can interact with platelets and trigger the coagulation cascade in response to inflammatory stimuli, resulting in the formation of microthrombi which help contain the spread of pathogens, but also contribute to organ dysfunction. Platelet glycoprotein receptor GPIb-α binds to von Willebrand factor and mediates cross-linking of platelets and thrombosis. In the multicenter Thilo trial, we measured plasma levels of GPIb-α to correlate our measurements with the clinical presentation of ARDS.

GPIb-α plasma levels were measured on the first 5 days after study inclusion in 125 ARDS patients. Plasma levels of GPIb-α of survivors and non-survivors were compared; additionally, we issued a receiver operating characteristics (ROC) curve of GPIb-α levels and performed a survival analysis of patients stratified by their GPIb-α plasma levels. Multivariate Cox analysis was performed to identify risk factors for mortality.

Cox analysis showed that low GPIb-α levels were associated with higher mortality. In survivors, GPIb-α levels were significantly higher than in non-survivors. ROC analysis revealed an AUC value of 0.73 for the biomarker. For the Kaplan-Meier curve, patients with the lowest GPIb-α levels (0-130 ng/mL) had a mortality rate of 53%; in patients with higher levels (341-850 ng/mL), the mortality rate was 10%.

We are the first to report a role for platelet GPIb-α as a potential biomarker in ARDS. Lower GPIb-α plasma levels were associated with a higher mortality rate in ARDS. Diminished plasma levels might point to a higher consumption of the receptor, with an unfavorable effect on overall survival.

EUDRA-CT: 2016-003168-37. Registered on 12/04/2017. ClinicalTrials.gov: NCT03111212. Registered on 04/06/2017.