Why are most people able to tolerate cat’s hair while some people have severe reactions to the ubiquitous and practically invisible dust mites?
A recent SciTech Daily article followed La Jolla Institute scientists as they searched for the answer.
The researchers, through their June 12, 2020 study Science Immunology, have identified T cells that could prevent allergic reactions caused by dust mites or other allergens.
Referring to the previously unknown subset of T cells, one of the co-authors of the study remarked that their discovery will lead to many other therapeutic opportunities.
A Typical Reaction
Our immune systems’ reaction to a foreign substance results in allergies.
Typical allergic reactions to allergens are runny nose, congested nasal passages, and of course, sneezing. People with asthma may experience a life-threatening asthma attack.
Single Cell Genomics
Until now, scientists have only been able to explore the body’s forty trillion cells and two hundred cell types in bulk. But there are many questions, such as those involving cancer, that can only be answered by examining a single cell.
For instance, the onset of cancer begins when a cell’s DNA is mutated and the cell grows out of control. This eventually leads to the growth of tumors.
Other systems in the body including the brain, immune system, and blood involve cellular diversity. Therefore, a thorough knowledge of individual cells in these systems is essential.
Thanks to new techniques that isolate cells called single-cell genomics, scientists can explore the full complement of DNA (the genome).
The Study: House Dust Mite Allergy (HDM)
The team used a La Jolla Institute-led resource that stores data on the interactions of the immune system and HDM.
The scientists used microscopic HDMs as models for the study because they are so widespread that almost everyone has been exposed to them.
The La Jolla resource was used to determine which molecules and genes were produced when reacting to the HDM allergens.
Participants in the study were divided into four groups. One group with asthma and HDM allergy, one group with HDM only, a third group with asthma only, and the fourth group consisting of healthy subjects.
The study brought results. The blood of people who had HDM-allergic asthma contained a higher number of helper T cells than the blood of people who only had the HDM allergy.
Asthma and Inflammation
T helper cell 2 (Th2) is a type of inflammation associated with asthma and asthma’s abnormal response to harmless airborne particles. Under normal circumstances, regulatory T cells would be able to suppress these reactions and maintain airway clearance.
In contrast to the asthma group, the scientists identified a subset of T cells in the non-allergic group. These cells were enhanced by a gene that instructs a protein named TRAIL.
Upon further examination, the researchers suggested that TRAIL would be relevant as it would be able to lessen the activation of the aforementioned helper T cells.
In summary, the scientists have discovered a subset of T cells that appear to control allergic reactions to dust mites or other allergens.
This large-scale study represents the first single-cell transcriptomic RNA-seq study for La Jolla Institute. The information derived from this study may now be used to study many other diseases.
These findings present the challenge of boosting T cell activation in allergic and asthmatic populations.
Similar studies may identify at-risk children. Early detection could give physicians the opportunity to prevent the development of the disease.