Microparticles Provide a Novel Biomarker To Predict Severe Clinical Outcomes of Dengue Virus Infection

Abstract

Shedding of microparticles (MPs) is a consequence of apoptotic cell death and cellular activation. Low levels of circulating MPs in blood help maintain homeostasis, whereas increased MP generation is linked to many pathological conditions. Herein, we investigated the role of MPs in dengue virus (DENV) infection. Infection of various susceptible cells by DENV led to apoptotic death and MP release. These MPs harbored a viral envelope protein and a nonstructural protein 1 (NS1) on their surfaces. Ex vivo analysis of clinical specimens from patients with infections of different degrees of severity at multiple time points revealed that MPs generated from erythrocytes and platelets are two major MP populations in the circulation of DENV-infected patients. Elevated levels of red blood cell-derived MPs (RMPs) directly correlated with DENV disease severity, whereas a significant decrease in platelet-derived MPs was associated with a bleeding tendency. Removal by mononuclear cells of complement-opsonized NS1-anti-NS1 immune complexes bound to erythrocytes via complement receptor type 1 triggered MP shedding in vitro, a process that could explain the increased levels of RMPs in severe dengue. These findings point to the multiple roles of MPs in dengue pathogenesis. They offer a potential novel biomarker candidate capable of differentiating dengue fever from the more serious dengue hemorrhagic fever. IMPORTANCEDengue is the most important mosquito-transmitted viral disease in the world. No vaccines or specific treatments are available. Rapid diagnosis and immediate treatment are the keys to achieve a positive outcome. Dengue virus (DENV) infection, like some other medical conditions, changes the level and composition of microparticles (MPs), tiny bag-like structures which are normally present at low levels in the blood of healthy individuals. This study investigated how MPs in culture and patients' blood are changed in response to DENV infection. Infection of cells led to programmed cell death and MP release. In patients' blood, the majority of MPs originated from red blood cells and platelets. Decreased platelet-derived MPs were associated with a bleeding tendency, while increased levels of red blood cell-derived MPs (RMPs) correlated with more severe disease. Importantly, the level of RMPs during the early acute phase could serve as a biomarker to identify patients with potentially severe disease who require immediate care. E ach year, up to 390 million people are infected by dengue virus (DENV), the most significant mosquito-borne virus of the Flaviviridae family, posing serious socioeconomic and health burdens globally (1). Four serotypes of viruses (DENV serotype 1 [DENV-1], DENV-2, DENV-3, and DENV-4) are transmitted to humans by Aedes mosquitoes to establish both endemic and epidemic transmission cycles primarily in tropical and subtropical countries (1). Although the majority of DENV infections in humans are subclinical, a small fraction of infected individuals develops clinical symptoms ranging from a self-...

Different phenotypes of non‐classical monocytes associated with systemic inflammation, endothelial alteration and hepatic compromise in patients with dengue

“…Taking this information into consideration, along with an increase in the frequency of endothelium‐derived MPs, it is possible to hypothesize that the non‐classical monocytes could mediate part of the endothelial dysfunction characteristic of this disease. Moreover, it is worth mentioning that MPs have been proposed previously as biomarkers of predisposition to develop severe manifestations in dengue infection …”

“…Moreover, it is worth mentioning that MPs have been proposed previously as biomarkers of predisposition to develop severe manifestations in dengue infection. 43 3) The hepatic compromise (increase in AST and ALT) was associated with markers related to the activation and differentiation 20,21,44 of mononuclear phagocytes, such as CD86, HLA-DR, CD68 and CD14, suggesting a relationship between the effector response of these monocytes and the hepatic damage present in these patients. The increase in the expression of CD14 and intracellular CD68 detected in non-classical monocytes of dengue patients could suggest that these cells are in the process of differentiation in response to infection.…”

Secreted NS1 Protects Dengue Virus from Mannose-Binding Lectin–Mediated Neutralization

“…Soluble NS1 enhances infection in hepatocyte cell lines (7), elicits autoantibodies that cross-react with platelets and extracellular matrix proteins, and promotes endothelial cell damage via antibody-dependent complement-mediated cytolysis (8-10). Moreover, soluble NS1 facilitates immune complex formation and complement activation, which can trigger microvesicle shedding from erythrocytes (6, 11). Soluble hexameric NS1 associates with lipids and forms lipoprotein particles that can impact vascular endothelial function and integrity (12, 13).…”

The Fluid Membrane determines Mechanics of Red Blood Cell Extracellular Vesicles and is Softened in Hereditary Spherocytosis

“…8 RBC EVs have been suggested to postpone the clearance of RBCs by the immune system 9 , to play a role in blood clotting 10 and they have been put forward as a potential biomarker for dengue virus infections. 11 In patients with RBC infections such as malaria, the number of EVs is often elevated. 12,13 During malarial infection, RBC EVs were demonstrated to facilitate communication between malaria parasites.…”