Predictive value of Th17/Treg immune imbalance for disease severity and poor prognosis in children with respiratory syncytial virus pneumonia

Minjuan ZhuJian Liu^*

• The People’s Hospital of Suzhou New District, Suzhou, China

Objective: Respiratory syncytial virus pneumonia (RSVP) remains a major cause of pediatric hospitalization. This study evaluates the value of Th17/Treg imbalance in assessing disease severity and predicting prognosis among RSVP children. Methods: RSVP children (422 cases) during May 2022-May 2024 were retrospectively enrolled and divided into mild and moderate-to-severe groups based on disease severity. Additionally, 358 healthy children were recruited (the control group). Peripheral blood Th17 and Treg cell proportions were quantified by flow cytometry, with the Th17/Treg ratio calculated. Serum IL-17, IL-6, IL-10, and TGF-β1 levels were measured using ELISA. Logistic regression models were established to identify risk factors for poor prognosis. ROC curves were plotted to evaluate predictive performance. Results: RSVP children demonstrated higher Th17 cell proportion, IL-17 and IL-6 levels, and Th17/Treg ratio than controls, alongside lower Treg cell proportion and IL-10 and TGF-β1 levels (all P<0.001). These alterations correlated with disease severity and prognosis. Th17/Treg ratio and IL-17 were independent risk factors for poor prognosis, while IL-10 was a protective factor (all P<0.05). The Th17/Treg ratio yielded an AUC of 0.831 (77.05% sensitivity, 77.01% specificity) for predicting poor prognosis. AUCs were 0.770 for IL-17 (67.21% sensitivity, 78.67% specificity) and 0.756 for IL-10 (57.38% sensitivity, 83.38% specificity). The combined model (Th17/Treg ratio + IL-17 + IL-10) achieved a superior AUC of 0.919 (93.44% sensitivity, 75.35% specificity; all P<0.001). Conclusion: Peripheral blood Th17/Treg imbalance is a characteristic of RSVP children. The combined detection of Th17/Treg ratio, IL-17, and IL-10 can help predict poor prognosis in affected children.