Allergic Reactions and TH9 Helper T Cells

How interleukin-9 and T helper 9 cells regulate allergic airway inflammation might elucidate the process of allergic disease.

T_H2 helper T cells modulate reagenic allergic reactions. T_H2 cells secrete the interleukins IL-4, IL-5, and IL-13, and, it was thought until recently, IL-9. Now we know that IL-9 is secreted by a specific subset of CD4⁺ helper T cells called (logically) T_H9 cells. Regulated by a unique transcription factor called PU.1, T_H9 cells may have important roles in eliciting the allergic airway inflammation leading to asthma.

To define the function of T_H9 cells in disease, investigators studied the peripheral blood of atopic and nonatopic donors. They found significantly higher numbers of circulating T_H9 cells in the blood of the allergic patients. They also found that T_H9 cells accumulated rapidly in the lungs of house-dust–allergic mice after antig…

Reviewing Author

Mark V. Dahl, MD

Disclosures

Consultant / Advisory board Ulthera, Inc.; AuBio LifeSciences, LLC; Paris Therapeutics

Equity Elorac, Inc.; Makucell, Inc.; Paris Therapeutics

Editorial boards UpToDate

Leadership positions in professional societiesNational Rosacea Society (Chairman, Medical Board)