RNA Sequencing Analysis of CD4+ T Cells Exposed to Airway Fluid From Children With Pediatric Acute Respiratory Distress Syndrome.

CD4⁺ T cells contribute to lung inflammation in acute respiratory distress syndrome. The CD4⁺ T-cell response in pediatric acute respiratory distress syndrome (PARDS) is unknown.

Objectives: To identify differentially expressed genes and networks using a novel transcriptomic reporter assay with donor CD4⁺ T cells exposed to the airway fluid of intubated children with mild versus severe PARDS.

Design: In vitro pilot study.

Setting: Laboratory-based study using human airway fluid samples admitted to a 36-bed university-affiliated pediatric intensive care unit.

Patients/subjects: Seven children with severe PARDS, nine children with mild PARDS, and four intubated children without lung injury as controls.

Interventions: None.

Measurements and main results: We performed bulk RNA sequencing using a transcriptomic reporter assay of CD4⁺ T cells exposed to airway fluid from intubated children to discover gene networks differentiating severe from mild PARDS. We found that innate immunity pathways, type I (α and β), and type II (γ) interferon response and cytokine/chemokine signaling are downregulated in CD4⁺ T cells exposed to airway fluid from intubated children with severe PARDS compared with those with mild PARDS.

Conclusions: We identified gene networks important to the PARDS airway immune response using bulk RNA sequencing from a novel CD4⁺ T-cell reporter assay that exposed CD4⁺ T cells to airway fluid from intubated children with severe and mild PARDS. These pathways will help drive mechanistic investigations into PARDS. Validation of our findings using this transcriptomic reporter assay strategy is needed.