In a recent study, researchers found evidence for autoimmunity as a contributor to thrombosis in patients with polycythemia vera (PV). They reported their findings in the journal Diagnostics (Basel).
The researchers explained in their report that PV can cause thrombosis, and a common mutation with PV, JAK2 V617F, is linked to inflammation and autoimmunity. However, they noted, a connection between inflammation or autoimmunity and thrombosis with PV has not been certain. The researchers set out to examine various markers of inflammation and immunity in the context of PV and in patients with or without thrombosis.
In this retrospective study, previously collected blood samples were analyzed from 60 patients with PV who were receiving phlebotomy treatment. The researchers analyzed JAK2 V617F allele burden in these patients. The researchers also evaluated levels of autoimmune Th17 cells, interleukin-17 (IL-17) cells, anti-endothelial cell antibodies (AECAs), endothelial leukocyte adhesion molecule-1 (ELAM-1), intercellular adhesion molecule-1 (ICAM-1), and von Willebrand factor antigen (VWF:Ag) from patients’ collected samples. The researchers performed analyses with respect to the presence or absence of thrombosis in these patients. Additionally, blood samples were analyzed from 50 donors who served as control individuals.
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Of the 60 patients included in this analysis, 40 (67%) developed thrombosis in a 6.5-year median follow-up period. Thrombosis was arterial in most cases (30 patients), with the remaining 10 patients having venous thrombosis.
Patients with thrombosis showed a higher JAK2 V617F allele burden (75%) than patients without thrombosis did (25%; P <.001). Th17 levels were also significantly higher in those with thrombosis (0.85 + 0.48%) than in patients without thrombosis (0.40 + 0.22%; P <.004), and they were higher than Th17 levels in control individuals (0.27 + 0.20%). IL-17 levels were also significantly higher in patients with thrombosis (6.30 + 0.8 pg/mL) than in patients without thrombosis (3.20 + 0.9 pg/mL; P <.005), and they were higher than in control individuals (2.10 + 0.3 pg/mL). ELAM-1, ICAM-1, and VWF:Ag levels were also higher in patients with thrombosis than without thrombosis or in control individuals.
AECAs of the immunoglobulin G class showed a significantly higher enzyme-linked immunosorbent assay (ELISA) ratio in patients with thrombosis (25.1 + 10.1), compared with patients without thrombosis (1.8 + 2.0) and control individuals (1.7 + 2.2). Further analyses involving sera from AECA-positive patients with thrombosis indicated that AECA may be a contributor to vascular injury.
The researchers considered this study to provide evidence that serum AECAs are present in patients with PV and are associated with thrombosis. “This clinical observation may support the concept that autoimmunity and inflammation may be important factors in the pathogenesis of thrombosis in PV,” they wrote in their report. They suggested that AECA measurement may be recommended for patients with PV.
Reference
Cacciola R, Gentilini Cacciola E, Vecchio V, Cacciola E. Impact of anti-endothelial cell antibodies (AECAs) in patients with polycythemia vera and thrombosis. Diagnostics (Basel). 2022;12(5):1077. doi:10.3390/diagnostics12051077
