Association of human leucocyte antigen loci with vaccine-induced immune thrombotic thrombocytopenia: Potential role of the interaction between platelet factor 4-derived peptides and MHC-II.

No risk factors have been identified for vaccine-induced immune thrombotic thrombocytopenia (VITT) so far. The aim of this study was to identify human leucocyte antigen (HLA) alleles potentially associated with VITT susceptibility. Specific HLA class II alleles were detected with significantly higher frequency in VITT patients compared with Italian controls: DPB1*17:01, DQA1*05:01, and DRB1*11:04.

Deletion of tissue factor pathway inhibitor isoform beta or gamma, but not alpha, improves clotting in hemophilic mice.

Background: Tissue factor pathway inhibitor (TFPI) regulates tissue factor-triggered coagulation. Humans and mice express transcripts encoding for multidistributed (endothelial, platelet, and plasma) 3-Kunitz domain TFPIα and endothelial membrane-anchored 2-Kunitz TFPIβ. Mice express a third transcript, γ, that encodes plasma lipoprotein-associated 2-Kunitz TFPI.

Multiomic profiling reveals metabolic alterations mediating aberrant platelet activity and inflammation in myeloproliferative neoplasms.

Platelets from patients with myeloproliferative neoplasms (MPNs) exhibit a hyperreactive phenotype. Here, we found elevated P-selectin exposure and platelet-leukocyte aggregates indicating activation of platelets from essential thrombocythemia (ET) patients. Single-cell RNA-seq analysis of primary samples revealed significant enrichment of transcripts related to platelet activation, mTOR, and oxidative phosphorylation in ET patient platelets.

Heterogeneity in the half-life of factor VIII concentrate in patients with hemophilia A is due to variability in the clearance of endogenous von Willebrand factor.

Background: Previous studies have reported marked interindividual variation in factor VIII (FVIII) clearance in patients with hemophilia (PWH) and proposed a number of factors that influence this heterogeneity.

Objectives: To investigate the importance of the clearance rates of endogenous von Willebrand factor (VWF) compared with those of other FVIII half-life modifiers in adult PWH.

Methods: The half-life of recombinant FVIII was determined in a cohort of 61 adult PWH.