Monocyte Dynamics in Chikungunya Fever: Sustained Activation and Vascular-Coagulation Pathway Involvement

Area of Science:

• Immunology
• Virology
• Infectious Diseases

Background:

• Chikungunya fever (CF), caused by Chikungunya virus (CHIKV), presents with debilitating joint pain.
• Monocytes are crucial for immune response and viral replication during CHIKV infection.

Purpose of the Study:

• To evaluate the clinical and immunological profiles of patients with laboratory-confirmed Chikungunya fever.
• To investigate the role of monocyte subsets and associated immune markers in CHIKV infection.

Main Methods:

• Analysis of clinical symptoms and laboratory-confirmed CHIKV-infected patients.
• Flow cytometry to assess Toll-like receptor (TLR) expression on monocyte subsets (CD14+CD16+, CD14+CD16++).
• Measurement of soluble CD163 (sCD163), Tissue Factor (TF), Tissue Factor Pathway Inhibitor (TFPI), Epidermal Growth Factor (EGF), and Vascular Endothelial Growth Factor (VEGF) levels.

Main Results:

• Increased TLR4 expression in non-classical monocytes (CD14+CD16++) and enriched TLR7+ intermediate (CD14+CD16+) and non-classical monocytes during acute and chronic phases.
• Elevated sCD163 levels indicate sustained monocyte/macrophage activation.
• Increased coagulation mediators (TF, TFPI) observed, despite rare hemorrhagic events.
• Patients with arthritis showed higher TLR7+ intermediate monocytes and EGF; those with edema had increased VEGF.

Conclusions:

• CHIKV infection induces differential activation of CD16+ monocyte subsets.
• Elevated TLR expression and sCD163 suggest prolonged immune pathway activation and serve as markers of monocyte/macrophage activation in CHIKV infection.
• Specific monocyte profiles correlate with clinical manifestations like arthritis and edema.