Have you ever wondered what either groups you together or separates you from allergy sufferers? In the case of indoor dust mite allergies and asthma triggers, some people are very sensitive to these allergens and others don’t appear to be affected at all. This summer, scientists discovered a specific immune cell that is present in people who don’t have an allergic response when dust mite allergens are present.
This immune cell belongs to a group called T-cells. Scientists from La Jolla Institute for Immunology investigated dust mite allergy because it’s an ever-present allergen to which everyone is exposed. Dust mites are microscopic, indoor pests that live off of dead skin and dander particles from humans and animals. They are so prevalent that it’s incredibly difficult—if not nearly impossible—to remove them from our environments, making them the perfect allergen to study in different groups of people.
While some people don’t develop full-blown allergies or asthmatic inflammation from exposure to house dust mites, everyone reacts to one extent or the other while the body recognizes the house dust mite. For this study, people were recruited and split into 4 groups: healthy participants, those allergic to dust mites, those allergic to dust mites and also asthmatic, and asthmatics with no dust mite allergy.
The T-cells in the immune system are considered “helper cells,” a specific type of white blood cell. These newly discovered cells form a subset called interleukin-9 (Th2), a cytokine which regulates autoimmune and allergic reactions. In people who have allergies to house dust mites and asthma, levels of this T cell are higher in the blood than is found in the people with only allergies to dust mites.
People who did not have an allergic reaction from dust mites possessed another subset of helper T-cells which had an extra gene for encoding a protein. The TRAIL protein (Tumor necrosis factor-related apoptosis-inducing ligand) causes the process of cell death to occur. In the case of non-allergic individuals, their helper T cells’ extra gene prompts cell death and could regulate and temper the activation of other helper T cells.
The discovery of these immune cell subsets in individuals which predisposes an immune system to allergies or asthma could lead to better early intervention and screening in the future.
Grégory Seumois, Ciro Ramírez-Suástegui, Benjamin J. Schmiedel, Shu Liang, Bjoern Peters, Alessandro Sette, Pandurangan Vijayanand. Single-cell transcriptomic analysis of allergen-specific T cells in allergy and asthma. Science Immunology, 2020; 5 (48): eaba6087 DOI: 10.1126/sciimmunol.aba6087