An article in The American Journal of Respiratory and Critical Care Medicine discussed recent research of the heterogeneity or diversity of asthma. The thrust of the research project was to try to explain the variable benefit that asthmatics receive from inhaled corticosteroids.
It has been observed for quite some time that while many asthmatics show a marked improvement in their breathing with the use of inhaled steroids, there are others whose response to steroids is modest or nonexistent. Inhaled steroids have been a mainstay in asthma management for years. Because it is known that asthma occurs due to inflammation in the airways, steroids are potent anti-inflammatories and, hence, the predictable nature of their benefit.
Inflammation is defined as the incursion of white blood cells from the blood stream into the inflamed tissue. As it turns out, the type of white blood cell found in asthmatics determines how they respond to steroids. If the white blood cell is an eosinophil, then the patients have greatly benefitted by the inhaled steroids. If the white blood cell is a neutrophil, then steroids have been much less effective.
The researchers used a relatively test called sputum cytology. They collected multiple samples of sputa from a large number of asthmatics. These were sent to a special pathology lab to determine the type of anti-inflammatory cell: eosinophil or neutrophil. The researchers had already separated the asthmatics into groups of “steroid responders” and “steroid non-responders.” The two groups matched up perfectly with the cell type eosinophil or neutrophil respectively.