Peripheral blood double-negative T cells percentage as a reliable biomarker for the prediction and diagnosis of pneumonia in pregnant women with influenza.

BACKGROUND

Pregnant women are at high risk of influenza-related pneumonia, but early predictive biomarkers are lacking.

OBJECTIVE

The aim of the study is to identify the differences between influenza A and B infections and to determine reliable diagnostic biomarkers for predicting the development of pneumonia in pregnant women with influenza.

STUDY

DESIGN

A total of 120 pregnant women with laboratory-confirmed influenza were enrolled in the study, including 60 cases of influenza A (H1N1) and 60 cases of influenza B (Victoria). Clinical data were collected, and laboratory tests were performed to assess peripheral blood TBNK cell subsets, CD64 expression, and cytokine levels. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with pneumonia in pregnant women with influenza, and the diagnostic performance was assessed using the area under the receiver operating characteristic curve (AUROC).

RESULTS

Compared to those with influenza B, pregnant women infected with influenza A experienced more frequent coughing but less sputum production and sore throat. Additionally, they exhibited significantly higher levels of several inflammatory markers, including leukocyte count, neutrophil-to-lymphocyte ratio (NLR), IFN-γ, neutrophil CD64 (nCD64) index, monocyte CD64 (MoCD64), and polymorphonuclear neutrophil CD64 (PMNCD64). Notably, univariate analysis and multivariate analysis further identified DNT% and IL-2 as independent predictors of pneumonia development in pregnant women with influenza, with odds ratios (95% CI) of 1.59 (1.00-2.53) and 0.37 (0.14-0.98), respectively. Among the biomarkers evaluated, the DNT% demonstrated the highest diagnostic performance, with an AUROC of 0.8925 (P < 0.0001) and an optimal cutoff value of 1.66, yielding 90% sensitivity, 91% specificity, and a negative predictive value (NPV) of 98%.

CONCLUSIONS

Pregnant women infected with influenza A and B exhibit distinct clinical and immunological profiles. Elevated DNT% and decreased IL-2 levels independently predicted pneumonia development, irrespective of other clinical factors such as timing of oseltamivir administration. Among all biomarkers assessed, DNT% showed the highest diagnostic accuracy, highlighting its potential as a reliable early indicator for identifying pregnant women with influenza at risk of pneumonia progression.