Erythrocytes from patients with myeloproliferative neoplasms and splanchnic venous thrombosis show greater expression of Lu/BCAM

IntroductionLutheran/BCAM protein (Lu) on the surface of erythrocytes is key for their adhesion to the endothelium, and erythrocytes from individuals with JAK2V617F-mutated myeloproliferative neoplasms (MPN) have increased endothelial adhesion. Splanchnic vein thrombosis (SVT) is a devastating thrombotic complication of MPN, and frequently, the only diagnostic feature is the JAK2V617F mutation. We sought to examine whether erythrocytes from patients with JAK2V617F mutated SVT (MPN-SVT) exhibited increased Lu expression, thereby supporting a mechanistic contribution to the development of thrombosis. MethodsWe report the validation of a novel flow cytometry assay for Lu expression on erythrocytes. We examined the expression of Lu on erythrocytes from a cohort of MPN patients with and without SVT, and healthy controls. Samples were obtained from 20 normal individuals, 22 with MPN (both JAK2V617F-mutated and wild-type) and 8 with JAK2V617F-mutated MPN-SVT. ResultsLu expression by erythrocytes from patients with MPN and MPN-SVT is significantly increased compared to erythrocytes from healthy individuals (P<.05), but there was no significant difference between patients with MPN-SVT and MPN. ConclusionsPatients with MPN have increased expression of the red cell Lu/BCAM adhesion molecule. Further work is required to determine the role of the increased Lu/BCAM adhesion to the endothelium in the development of thrombosis in MPN of all genotypes.