Galectin-9 plasma levels reflect adverse hematological and immunological features in acute dengue virus infection

Abstract

Background: Dengue virus (DENV) infection remains a major public health burden worldwide. Soluble mediators may play a critical role in the pathogenesis of acute DENV infection. Galectin-9 (Gal-9) is a soluble β-galactoside-binding lectin, with multiple immunoregulatory and inflammatory properties.

Objective: To investigate plasma Gal-9 levels as a biomarker for DENV infection.

Study design: We enrolled 65 DENV infected patients during the 2010 epidemic in the Philippines and measured their plasma Gal-9 and cytokine/chemokine levels, DENV genotypes, and copy number during the critical and recovery phases of illness.

Results: During the critical phase, Gal-9 levels were significantly higher in DENV infected patients compared to healthy or those with non-dengue febrile illness. The highest Gal-9 levels were observed in dengue hemorrhagic fever (DHF) patients (DHF: 2464 pg/ml; dengue fever patients (DF): 1407 pg/ml; non-dengue febrile illness: 616 pg/ml; healthy: 196 pg/ml). In the recovery phase, Gal-9 levels significantly declined from peak levels in DF and DHF patients. Gal-9 levels tracked viral load, and were associated with multiple cytokines and chemokines (IL-1α, IL-8, IP-10, and VEGF), including monocyte frequencies and hematologic variables of coagulation. Further discriminant analyses showed that eotaxin, Gal-9, IFN-α2, and MCP-1 could detect 92% of DHF and 79.3% of DF, specifically (P<0.01).

Conclusion: Gal-9 appears to track DENV inflammatory responses, and therefore, it could serve as an important novel biomarker of acute DENV infection and disease severity.

Keywords: Biomarker; Dengue fever; Dengue hemorrhagic fever; Dengue virus; Galectin-9.

Fig. 1. Plasma levels of galectin-9 in dengue virus infected individuals

A) Significantly different levels of plasma galectin-9 in the critical phase of patients with DF and DHF as well as in non-dengue febrile illness (patients with leptospirosis) and healthy controls (Kruskal-Wallis test, P<0.0001). Dunn’s multiple comparison tests showed significant differences between healthy controls and DF/DHF patients (P<0.001), and between non-dengue febrile illness and DF/DHF. B) No significant differences in galectin-9 levels between 4 serotypes (Kruskal-Wallis test). C) Changes in the plasma levels of galectin-9 from the critical to recovery phases in patients with DF and DHF. Abbreviations: DF, dengue fever; DHF, dengue hemorrhagic fever

Fig. 2. Significant changes in cytokine/chemokine and galectin-9 levels in DENV infected patients

Median fold changes in galectin-9 and cytokine/chemokine levels were calculated as: median of the critical phase from DENV infected patients/median of HCs. The differences between the levels of patients and HCs were evaluated by Mann-Whitney test. DENV, dengue virus; HCs, healthy controls

Fig. 3. Results of stepwise multiple regression analysis when galectin-9 was set as a dependent variable

Significantly elevated cytokine/chemokines such as IL-10, IP-10, IL-1α, MIP-1α, IL-8, IFN-g, MCP-1, TNF-α, GM-CSF, IFN-α2, IL-15, eotaxin, IL-1Ra, MIP-1b, VEGF, and EGF were included as independent variables in models A and B. WBC, lymphocyte, monocyte, neutrophil, RBC, Hg, Hct, and Plt were used as independent variables in models C and D; virus titers were only obtained in the critical phase (C). Abbreviations: mo, monocyte; Hct, hematocrit; Plt, platelet count.