M2 macrophage subset decrement is an indicator of bleeding tendency in pediatric dengue disease

Dengue disease is widespread in tropical and sub-tropical regions. Severe dengue infection is characterized by plasma leakage, fluid accumulation, severe bleeding, or vital organ impairment. Bleeding is a critical complication of dengue disease. However, the biomarkers of dengue disease are still unknown. Macrophages have a distinct polarization phenotype related to M1/M2 classification. Macrophage polarization toward the pro-inflammatory M1 phenotype is considered critical for efficient antiviral immune responses, whereas the anti-inflammatory M2 phenotype is considered essential for tissue remodeling. We investigated macrophage polarization patterns in the peripheral blood of pediatric patients with dengue disease.

Medical records and laboratory data were collected from 23 pediatric healthy controls and 100 dengue disease samples from 50 dengue patients. Macrophage polarization-related surface markers were assessed using flow cytometry.

The percentage of macrophages in the peripheral blood was higher in dengue patients than in the healthy controls. The percentages of M2a and M2c macrophage subsets were higher and the percentage of M1 macrophage subset was lower in dengue patients than in healthy controls. However, the percentages of M1, M2a and M2b macrophage subsets in dengue patients with bleeding tendency were lower than that without bleeding tendency. The percentages of M2a, M2b, and M2c macrophage subsets were positively correlated with platelet counts.

Decreased the percentages of M2 macrophage subsets in pediatric dengue patients are associated with bleeding tendency and lower platelet counts.