Effects of immunotherapy on the inflammation in pollen asthma

Seasonal asthma is a natural model of airway inflammation where amount of airborne antigen have direct impact and correlates to the clinical disease and degree of inflammation. Bronchial hyperresponsiveness (BHR) is an indirect measure of the degree of airway inflammation and the seasonal increase paralleling clinical disease has been shown in a number of studies. Using a model of seasonal asthma in birch pollen sensitive individuals we intended to prove the anti-inflammatory potential of immunotherapy (IT). Forty birch pollen-allergic patients, 20 IT-treated and 20 untreated participated in a series of studies. BHR expressed as PC20 histamine increased in all patients during the season although most in untreated controls; the difference between the groups was p < 0.07. The level of eosinophil cationic protein (ECP) rose in untreated, but not IT-treated, patients during the season (p < 0.05). Significant increase in eosinophil chemotactic activity (ECA) in serum of untreated patients during the season was noted. IT-treatment abrogated this response. After 2 years of treatment bronchoalveolar lavage (BAL) was performed on 12 patients (6 in each group). IT-treatment prevented seasonal rise of eosinophil numbers in peripheral blood (PB) and the lung while in the untreated group the increase was significant in both compartments (p < 0.05 and p < 0.01, respectively). At the same time, significant increment in ECP and ECA levels in BAL were recorded in untreated patients compared with IT-treated (p < 0.05, p < 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)