Role of Type 2 Inflammation in Asthma

Raffi Tachdjian, MD, MPH, FAAAAI, FACAAI: Dr Chase, I’m going to turn to you. We just started touching on type 2 inflammation. What is type 2 inflammation to you? What is its importance? And what percentage of patients with asthma qualify or fit into that category, and the broader scope of that?

Nicole Chase, MD, FAAP, FAAAAI, FACAAI: Type 2 inflammation is a driving factor for most patients with asthma. Studies have shown anywhere between 70%—and even upward of 80% or 90%—of patients classically have type 2 inflammation. When I think about it as an actual disease process, it’s more the idea that you have a T cell that, in the presence of a certain cytokine milieu—specifically the canonical type 2 cytokines of IL-4, IL-5, IL-13, etc—you see differentiation of that T cell into a type 2 helper T cell. Associated with that, we see downstream patterns and downstream markers that are associated with that endotype phenomenon. That being, we see the predominance of eosinophils, levels of immunoglobulin E, structural cells that are affected that include goblet cells, and whatnot—thinking about the production of disease markers, such as exhaled nitric oxide. Realistically, it’s this whole framework of thinking about how the pathway in the immune system that previously was thought to represent control of extracellular pathogens or whatnot has evolved separately from the types of inflammation we think of in terms of vaccines or autoimmune disease. And it’s really this narrow sliver of the immune system that relates to, again, these classic cytokines and what their involvement is in the T-cell differentiation process. And as Dr White mentioned, those classic diseases are thought to be driven by similar mechanisms. It’s really prominent and a predominant issue in terms of patients with asthma. In general, we see many patients otherwise who fit into this either at low or high levels across the board of type 2 inflammation.

Raffi Tachdjian, MD, MPH, FAAAAI, FACAAI: Very nicely said. An ever-developing field, which kind of helps us keep the job secure in a way.

Nicole Chase, MD, FAAP, FAAAAI, FACAAI: Absolutely.

Transcript edited for clarity