ABSTRACT
Accumulating patholological and physiological evidence in the last few years suggests
that the airway inflammation and remodeling that characterize asthma occur not only
in the central airways but extend to the distal lung and the lung parenchyma. The
distal airways are capable of producing T-helper (Th)2 cytokines as well as chemokines,
and more recently, they have been recognized as a predominant site of airflow obstruction
in asthmatics. A similar TH2-type cytokine profile and infiltration of inflammatory
cells has also been reported in the lung parenchyma. The inflammation at this distal
site has been described as more severe when compared with the large airway inflammation,
and evidence of remodeling in the lung periphery is emerging. Recognition of asthma
as a disease of the entire respiratory tract has an important clinical significance
highlighting the need also to consider the distal lung as a target in any therapeutic
strategy for effective treatment of this disease.
KEYWORDS
Distal airways - parenchyma - asthma - allergic inflammation