ABSTRACT
This chapter presents evidence that Interleukin-5 mRNA transcripts are detectable in T lymphocytes in ongoing steady-state asthma as well as asthma provoked by inhalational challenge. Asthma is characterized by infiltration of the bronchial mucosa with large numbers of activated eosinophils and the presence of elevated concentrations of eosinophil derived proteins such as major basic protein and the eosinophil cationic protein. The degree of the eosinophilia has been shown to correlate with the severity of airways hyper-responsiveness. The beneficial effects of corticosteroids in the treatment of asthma are well documented and the use of inhaled corticosteroids in chronic asthma is widely accepted. It has been suggested that corticosteroids mediate their beneficial role in the reversal of airway obstruction and bronchial hyperreactivity through an effect on T-cell-associated inflammatory processes. The numbers of mRNA+ cells in broncho-alveolar lavage n asthma and circulating concentrations of serum Interleukin-5 decrease after corticosteroid therapy.
