Measurement of inflammatory markers in the breath condensate of children with cystic fibrosis

Identifying noninvasive markers of pulmonary inflammation would be useful in assessing new therapies in children. Breath condensate is a simple and potentially acceptable sample medium even in small children. The technique has previously been used in adults, but not children with cystic fibrosis. The technique was assessed in 36 children with cystic fibrosis (mean age 10.4 yrs) and 17 control subjects, analysing samples for nitrite, interleukin(IL)-8 and salivary and nasal contamination. Correlations were made between levels of the inflammatory markers and forced expiratory volume in one second/forced vital capacity, chest radiograph score and use of inhaled steroids. On samples without significant contamination (<10 u.L-1 amylase) nitrite was detected in 93% of samples at a median concentration of 3.0 mu M compared with 50% of control samples at a median of 0.5 mu M. Condensate amylase levels did not correlate with the nitrite value obtained (r=0.31). IL-8 was detected in 33% of CP samples. Breath condensate is an acceptable method of sample collection in children. Nitrite was raised in breath condensate from patients with cystic fibrosis when compared with control subjects.