Neutrophils Track Dengue’s Course With a Distinct, Late Blood-Cell Nadir

Neutrophils behave differently in dengue than in other febrile illnesses, following a kinetic pattern so distinctive that transient neutropenia emerges as a hallmark of uncomplicated infection, according to a large pooled analysis of clinical studies conducted in Vietnam over two decades. The research, published in BMC Infectious Diseases, drew on 11,290 patients enrolled across nine studies between 1999 and 2018, with clinical and laboratory parameters recorded daily.

Of the full dataset, 6,082 patients had available neutrophil data. Within this subgroup, 4,071 had laboratory-confirmed dengue, verified by RT-PCR, NS1 detection, or IgM seroconversion, and 1,067 of them, or 26 percent, developed dengue shock syndrome as defined by WHO 1997 and 2009 criteria. The remaining 2,011 patients had other febrile illnesses. Participants were recruited across the clinical spectrum: 54.2 percent in outpatient settings, 28.9 percent at hospital admission, and 16.9 percent in intensive care units.

The analysis, which used linear mixed-effects models to characterize the trajectories of total white cell, neutrophil, and lymphocyte counts, found that neutrophil and total white cell counts declined during the febrile phase and reached their nadir on illness days 4 to 6. Lymphocytes behaved differently, reaching their nadir earlier, on days 2 to 3, a significantly distinct timing that the authors highlight as a defining feature of the neutrophil response in dengue.

Prevalence of transient neutropenia, defined as a count below 1.5 K/µL, varied sharply by diagnosis. It occurred in 84 percent of patients with uncomplicated dengue, compared with 47 percent of those with dengue shock syndrome and 33 percent of patients with other febrile illnesses. This inverse relationship with severity suggests that the marked neutrophil dip is most characteristic of milder dengue courses rather than of the most severe presentations.

The authors conclude that transient neutropenia is a hallmark of dengue infection, particularly in uncomplicated cases, and that neutrophils follow a kinetic profile clearly separated from lymphocytes by the later timing of their nadir. They frame these findings as evidence that neutrophil dynamics are closely linked to the clinical course of dengue, while cautioning that further mechanistic research is needed to clarify the cells’ role in pathogenesis and recovery. As an observational analysis of pooled clinical studies, the work characterizes associations between cell counts and disease categories rather than establishing causal mechanisms.

Subject of Research: Neutrophil count kinetics in dengue patients compared with other febrile illnesses in Vietnam

Article Title: Neutrophil kinetics in dengue patients compared to other febrile illnesses: results from 6082 patients in Vietnam

Article References: Vuong, N. L., Huyen, T. B., Duyen, H. T. L., Tam, D. T. H., Hoa, V. T. M., Trung, D. T., Van Ngoc, T., Quyen, N. T. H., Kieu, N. T. T., Truong, N. T., Chau, N. V. V., Tai, L. T. H., Lan, N. T. H., Lam, P. K., Wills, B. A., Nguyet, N. M., & Yacoub, S. (2026). Neutrophil kinetics in dengue patients compared to other febrile illnesses: results from 6082 patients in Vietnam. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14661-0

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14661-0

Keywords: dengue, neutrophils, neutropenia, white blood cells, lymphocytes, dengue shock syndrome, febrile illness, Vietnam, blood cell kinetics, clinical study, Neutrophil, kinetics