Hemostatic and platelet proteins are associated with bleeding grade and time to major bleed in hemato-oncological patients.

Bleeding crises are common complications in hemato-oncological patients undergoing chemotherapy and stem cell transplantation. Platelet transfusions are frequently administered to treat and prevent bleeding events at low platelet counts. However, the association between thrombocytopenia and bleeding events remains unclear, arguing for an improved understanding of pathophysiological changes underpinning bleeding events. Therefore, this study aims to identify plasma protein levels associated with bleeding events in a hemato-oncological patient population using unbiased mass spectrometry-based plasma profiling. Plasma samples and clinical records from 176 hemato-oncological patients included in the Pathogen Reduction Evaluation and Predictive Analytical Rating Score study were analyzed. Of 600 identified proteins, abundance levels of 55 proteins were found to be associated with bleeding severity at the time of sampling. Among these, a large cluster of platelet proteins (n = 48) as well as coagulation factor VII and vitamin K-dependent protein C were observed. Interestingly, 9 of these 55 proteins were also associated with the time to major bleeding event (World Health Organization grade ≥2). Platelet protein levels correlated with platelet counts but not with white cell counts or platelet transfusions. Taken together, our results suggest that lower abundance of platelet and coagulation proteins in plasma are associated with increased bleeding grade and time to major bleeding events in hemato-oncological patients. This highlights the potential for improved hemostatic monitoring of hemato-oncological patients at risk of bleeding, beyond platelet count alone.