PMC3095898_01
PMC3095898_02
Changes in FEV1 and histamine reactivity following bronchial provocation testing in four antibiotic manufacturing workers. Serial FEV1 measurements (y-axis) are plotted against time after provocation (x-axis); a fall of greater than 15% from baseline indicated a significant response. A late reaction (greater than two hours after challenge) is seen in all cases; an early reaction was also seen in case c. The numerical value associated with each challenge plot is the postchallenge histamine PC20 result (mg/ml histamine): the lower the PC20 the greater the degree of bronchial hyperresponsiveness.
JA2011-365683.001.jpg
PMC3095898_02_JA2011-365683.001.jpg
fig1
Each of the four developed a (predominantly) late asthmatic reaction (Figure 1) accompanied by increased bronchial hyperresponsiveness as demonstrated by a fall in histamine PC20 concentration following challenge; these findings were repeatable on further testing but not seen after identical exposure to lactose powder alone.