Air pollution impairs T-regulatory cells and may worsen asthma

Asthma is the most frequent chronic disease in children. Regulatory T (Treg) cells are suppressors of immune responses involved in asthma. Treg-cell impairment is associated with increased DNA methylation of Forkhead box transcription factor 3 (Foxp3), a key transcription factor in Treg-cell activity.

Children with and without asthma from California were enrolled in a cross-sectional study.

Treg-cell suppression was impaired and Treg-cell chemotaxis were reduced with ambient air pollution (AAP).

Foxp3 was decreased and contained higher levels of methylation with ambient air pollution (AAP).

Increased exposure to AAP is associated with hypermethylation of the Foxp3 locus, impairing Treg-cell function and increasing asthma morbidity. Ambient air pollution (AAP) could play a role in mediating epigenetic changes in Treg cells, which may worsen asthma.

Regulatory T cells - 5 groups have been described as of year 2010:

- CD4+CD25+ regulatory T cells ("classic" T regs)
- TR1 cells, CD4 cells that secrete IL-10

- Th3 cells, a subset of CD4+ cells that secrete TGF-b
- CD8+ suppressor T cells
- γ/δ T cells

Regulatory T cells - 6 groups have been described as of year 2010 (click to enlarge the image).


References:

Ambient air pollution impairs regulatory T-cell function in asthma. J Allergy Clin Immunol. 2010 Oct;126(4):845-852.e10.
Airways changes related to air pollution exposure in wheezing children: pollution decreases FEV1. ERJ, 2012.

Related reading:

Two Children, One Rich, One Poor, Gasping for Air in Delhi’s Smog - NYTimes http://buff.ly/2fyuxUI
Image source: A scanning electron microscope (SEM) image of a single human lymphocyte.Wikipedia, public domain.