Am. J. Respir. Crit. Care Med., Vol 151, No. 2, 02 1995, 340-344.
Bronchial inflammation in occupational asthma due to western red cedar
AJ Frew, H Chan, S Lam and M Chan-Yeung
Department of Medicine, Vancouver General Hospital, University of British Columbia, Canada.
Bronchoalveolar lavage cells and bronchial biopsies were obtained from nine
patients with red cedar asthma, six atopic asthmatics and six non- atopic,
non-asthmatic control subjects. There were similar proportions of
neutrophils, mast cells, lymphocytes, and macrophages in BAL samples from
all three groups, but eosinophil numbers were elevated in patients with
cedar asthma and atopic asthma (3.0 and 2.5% respectively versus 0.5% in
control subjects; p < 0.05 for each group). In bronchial mucosal
biopsies, mean numbers of T cells were elevated in both asthmatic groups
(cedar asthma 9.8 times, and atopic asthma 2.6 times, control values). CD4+
cells accounted for most of the increase in T- cell numbers, while CD8+
cell numbers were elevated in biopsies from a minority of cedar asthma
patients. Absolute numbers of CD25+ (IL-2 receptor-bearing) cells were
increased in cedar asthma but the proportion of T cells expressing CD25,
was similar in all three groups. Activated eosinophils (EG2+) were
increased in both asthmatic groups, with mean numbers 2.5 times greater in
the cedar asthma biopsies than in atopic asthmatics. Thus both cedar asthma
and atopic asthma are associated with increased numbers of T-cells and
activated eosinophils in the bronchial mucosa. There was no major
histologic difference between atopic asthma and red cedar asthma.
