Lymphocyte Subset Analysis by Flow Cytometry in Dengue Patients

Introduction- Symptoms of the mosquito-borne virus dengue may range from a low-grade fever to more serious complications including dengue shock condition and dengue hemorrhagic fever. Disease severity is largely influenced by host immune responses. T-lymphocyte subsets, particularly CD4⁺ and CD8⁺ cells, play an significant role in dengue immunopathogenesis, and their alterations may reflect immune dysregulation. Flow cytometry enables accurate enumeration of lymphocyte subsets and helps assess immune changes in dengue infection.

Aim-To enumerate CD4⁺ and CD8⁺ lymphocyte counts in dengue-infected patients using flow cytometry, standardize the enumeration method on a flow cytometry platform, and correlate CD4⁺ and CD8⁺ counts with the clinical severity of dengue, including uncomplicated and complicated cases.

Materials and Methods- The research was conducted at a tertiary care clinic including 35 laboratory-confirmed dengue cases (and 9 controls= total 44 cases) diagnosed by NS1 antigen and/or IgM antibody testing. Dengue cases were categorized into uncomplicated and complicated dengue based on clinical features and WHO criteria. Peripheral blood samples were composed in EDTA vacutainers as well as processed within six hours. CD4⁺ and CD8⁺ lymphocyte enumeration was performed using standardized protocols on a BD FACS Canto II flow cytometer. Statistical analysis was carried out with SPSS software.

Results-Age distribution among study groups was comparable. Dengue patients showed alterations in CD4⁺ and CD8⁺ lymphocyte counts compared with healthy controls. Patients with complicated dengue demonstrated greater deviations in lymphocyte subsets, indicating more pronounced immune dysregulation associated with disease severity.

Conclusion- Flow cytometric analysis of CD4⁺ and CD8⁺ lymphocyte subsets provides valuable insights into immune changes in dengue infection. Differences between uncomplicated and complicated dengue highlight the role of T-cell dysregulation in disease severity. Lymphocyte subset analysis may serve as a useful adjunct in evaluating disease progression and immune pathogenesis in dengue.