All of these measures will be repeated after 4 weeks (end of first treatment course), 8 weeks (before start of next treatment course), and 12 weeks (end of second treatment course). In addition, ABG and exhaled NO alone will be repeated at 2 weeks and 10 weeks (midway through each treatment period). Finally, blood (40 ml) will be drawn at time 0, 4, 8, 12 weeks and stored for measurement of future variables.