The following is a summary of “Chymase-1: a “MAST”-er switch in COPD?” published in the December 2022 issue of Respiratory by Kliment et al.

One of the most important defining aspects of chronic obstructive pulmonary disease (COPD) is the development of chronic inflammation in the lung tissue and airways. Therefore, this is one of the most essential identifying characteristics. In recent years, researchers have concluded that mast cells have a role in a variety of disorders, one of which is chronic obstructive pulmonary disease (also known as COPD) [1–4].

Mast cells are immune cells that have a relatively long lifespan and reside permanently in the tissue. These cells are responsible for modifying immunological responses; they also interact with antigen-presenting cells; they release proteases and chymases; for example, CMA1; and they connect with antigen-presenting cells [5]. When Ehrlich [6] published the very first description of these granule-filled cells in the year 1878, he wrote himself into the annals of history.

Even though mast cells have been demonstrated to have a part in asthma [7], the significance of mast cells in COPD is still mainly unknown at this point. It has been demonstrated that individuals who have been given a diagnosis with COPD have abnormalities in both the density of tissue-resident mast cells as well as their location [1, 2, 4, 8].