Effect of environmental exposure on bronchial sensitivity to antigen

Bronchial sensitivity to grass and ragweed extracts was determined in four adult asthmatic subjects at the beginning and end of the grass and ragweed pollen seasons. 4 subjects with ragweed sensitivity had increased bronchial sensitivity to ragweed antigen at the end of the ragweed season. 2 of 3 grass sensitive subjects demonstrated increased bronchial sensitivity to grass antigen after the grass pollen season. This study suggests that natural environmetnal exposure to pollen antigens may induce priming in the lung.