Dynamic landscape of peripheral blood lymphocyte subsets in dengue patients: a multimodal single-cell and flow cytometry analysis

BACKGROUND: Dengue fever is a mosquito - borne infectious disease caused by the dengue virus (DENV). Understanding its immune response mechanisms is crucial for developing effective treatments and vaccines, especially regarding the dynamic changes of peripheral blood lymphocyte subsets. Traditional immunological methods have limitations in accurately analyzing lymphocyte subsets and their functional dynamics. However, the combination of single - cell RNA sequencing and flow cytometry can explore the immune response of dengue patients more deeply. METHODS: We integrated four public datasets from the Gene Expression Omnibus (GEO), comprising samples from acute dengue patients, healthy individuals, and convalescent patients, for single-cell RNA sequencing analysis. The analysis included data preprocessing, cell annotation, functional enrichment, T cell state scoring, intercellular communication analysis, and pseudotime analysis. Additionally, we collected peripheral blood samples from 81 DENV-1-infected individuals and 30 healthy controls to analyze lymphocyte subsets, activation status, and apoptosis using flow cytometry. RESULTS: Single-cell RNA sequencing identified 11 cell clusters (including T cells, B cells, and plasma cells). Functional analyses demonstrated diverse roles of lymphocyte subpopulations in immune responses and metabolic regulation, as well as frequent intercellular communication. Pseudotime analysis revealed the differentiation trajectory of CD4⁺ naïve T cells and related signaling changes. Flow cytometry showed significantly decreased absolute T cell counts, altered subpopulation distribution and activation, and increased apoptosis; immunological marker variations existed among T cell subpopulations, with correlations between absolute and relative counts.In conclusion, dengue virus infection significantly impairs lymphocyte composition and function, causing immune dysregulation. This study provides insights into the dengue immune regulatory network, with potential implications for targeted immunotherapy and vaccine development, though its small sample size limits the findings and requires further research. CONCLUSIONS: Dengue virus infection significantly affects the composition and function of lymphocyte subsets, leading to immune dysregulation. This study provides new insights into the immune regulatory network of dengue fever and holds potential implications for the development of targeted immunotherapies and vaccines. However, the study has limitations, such as small sample size, and further research is needed in the future.