Chemotactic activity of bronchoalveolar lavage fluid from children with recurrent obstructive bronchitis.

Boyden's method was used to assess the chemotactic activity of bronchoalveolar lavage (BAL) fluid samples from patients aged 1-6 ys with recurrent obstructive bronchitis when signs of chronic mucosal inflammation were observed bronchoscopically. BAL was performed to reveal features of this mucosal inflammation by analysing the lavagable cells and soluble factors. In comparison with the chemotactic effect of casein, the activity of the fluid proved to be high for polymorphonuclear leukocytes (PMNs), but significantly low for mononuclear cells. After treatment of antibodies to C3 and C5, the activity was decreased considerably, but not to a minimum. Presumably, other chemo-attractants (leukotriens, enzymes) can also be found in the lavage fluid beside macrophage- or serum-derived and locally activated complement components. A comparison of complement components/albumin ratios in BAL fluid with serum complement components/albumin ratios suggested a significant local production and/or concentration of these factors. On the basis of our results, an accumulation of PMNs could be expected in the differential cell count, but an increased influx of macrophages was detected. Other amplifying or inhibitor systems may play an important role in the accumulation of PMNs in vivo.