Circulating microvesicles as novel biomarkers for pulmonary arterial hypertension in patients with systemic lupus erythematosus

Pulmonary arterial hypertension (PAH) is a serious complication of systemic lupus erythematosus (SLE) with increased mortality. A prothrombotic state may contribute to pathogenesis of SLE-PAH. Microvesicles (MVs) are known to be associated with thrombosis. Here, we investigated circulating MVs and their associations with SLE-PAH. Eighteen SLE-PAH patients, 36 SLE-non-PAH patients, and 36 healthy controls (HCs) were enrolled. Flow cytometry was used to analyze circulating MVs from leukocytes (LMVs), red blood cells (RMVs), platelets (PMVs), endothelial cells (EMVs), and Annexin V+ MVs with phosphatidylserine (PS) exposure. Plasma levels of all MV subgroups were elevated in SLE patients with or without PAH compared to HCs. Furthermore, plasma Annexin V+ MVs, LMVs, PMVs, RMVs, EMVs, and Annexin V+ RMVs were significantly elevated in SLE-PAH patients compared to SLE-non-PAH patients. Additionally, PAH patients with moderate/high SLE showed a significant increase in LMVs, PMVs, RMVs, Annexin V+ MVs, and Annexin V+ RMVs compared to SLE-non-PAH patients. However, PAH patients with inactive/mild SLE only exhibited elevations in Annexin V+ MVs, RMVs, and Annexin V+ RMVs. In the SLE-PAH patients, EMVs were positively correlated with pulmonary arterial systolic pressure, while PMVs and EMVs were positively correlated with right ventricular diameter. Moreover, the receiver operating characteristic curve indicated that Annexin V+ MVs, LMVs, PMVs, RMVs, EMVs and Annexin V+ RMVs can predict the presence of PAH in SLE patients. Importantly, multivariate logistic regression analysis showed that circulating levels of LMVs or RMVs, anti-nRNP antibody, and serositis were independent risk factors for PAH in SLE patients. Finally, our findings reveal that specific subgroups of circulating MVs contribute to the hypercoagulation state and the severity of SLE-PAH. Higher plasma levels of LMVs or RMVs may serve as biomarkers for SLE-PAH. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement the Tianjin Municipal Health Commission Funding grant (grant numbers KJ20028), National Natural Science Foundation of China (grant numbers 81370422), and Lupus Research Alliance (grant numbers 416805) ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee of Tianjin Medical University General Hospital fave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors