Single-Cell Profiling Reveals Immune Aberrations in Progressive Idiopathic Pulmonary Fibrosis

Area of Science:

• Immunology
• Pulmonology
• Genomics

Background:

• Peripheral blood cell population changes in idiopathic pulmonary fibrosis (IPF) are not well-characterized at single-cell resolution.
• Understanding these changes is crucial for identifying biomarkers and therapeutic targets in IPF.

Purpose of the Study:

• To create a detailed atlas of peripheral immune system alterations in stable and progressive IPF.
• To identify immune cell populations and molecular pathways associated with IPF progression and patient survival.

Main Methods:

• Single-cell RNA sequencing of peripheral blood mononuclear cells (PBMCs) from IPF patients and healthy controls.
• Flow cytometry validation in an independent cohort.
• Measurement of regulatory T cell (Treg) and monocyte chemoattractant protein levels in plasma and lung tissue.

Main Results:

• Classical monocytes and regulatory T cells (Tregs) were significantly increased in IPF patients compared to controls.
• Lymphocyte populations were decreased in IPF and further reduced in progressive IPF.
• Increased levels of CCL18 and CCL22, chemoattractants for Tregs, were observed in IPF, suggesting a lung-blood immune recruitment axis.

Conclusions:

• The peripheral immune landscape in IPF is characterized by an increase in classical monocytes and Tregs, which are predictive of disease outcomes.
• A potential immune recruitment axis between the lungs and blood exists in IPF, involving specific chemokines.
• This study provides a comprehensive single-cell view of immune dysregulation in IPF, offering insights into disease mechanisms and potential therapeutic strategies.